LinuxLists.cc - [PATCH] ARM: mmc: bcm281xx SDHCI driver

2013-05-09 05:56:17

Subject: [PATCH] ARM: mmc: bcm281xx SDHCI driver

Add SDHCI driver for the Broadcom 281xx SoCs. Also
add bindings for it into bcm281xx dts files.
Still missing:
- power managemement

Signed-off-by: Christian Daudt <[email protected]>

diff --git a/Documentation/devicetree/bindings/mmc/bcm,kona-sdhci.txt b/Documentation/devicetree/bindings/mmc/bcm,kona-sdhci.txt
new file mode 100644
index 0000000..ad1c4bd
--- /dev/null
+++ b/Documentation/devicetree/bindings/mmc/bcm,kona-sdhci.txt
@@ -0,0 +1,16 @@
+Broadcom BCM281xx SDHCI driver
+
+This file documents differences between the core properties in mmc.txt
+and the properties in the bcm281xx driver.
+
+Required properties:
+- compatible : Should be "bcm,kona-sdhci"
+
+Example:
+
+sdio2: sdio@0x3f1a0000 {
+ compatible = "bcm,kona-sdhci";
+ reg = <0x3f1a0000 0x10000>;
+ interrupts = <0x0 74 0x4>;
+};
+
diff --git a/arch/arm/boot/dts/bcm11351-brt.dts b/arch/arm/boot/dts/bcm11351-brt.dts
index 248067c..9ae3404 100644
--- a/arch/arm/boot/dts/bcm11351-brt.dts
+++ b/arch/arm/boot/dts/bcm11351-brt.dts
@@ -27,4 +27,21 @@
status = "okay";
};

+ sdio0: sdio@0x3f180000 {
+ max-frequency = <48000000>;
+ status = "okay";
+ };
+
+ sdio1: sdio@0x3f190000 {
+ non-removable;
+ max-frequency = <48000000>;
+ status = "okay";
+ };
+
+ sdio3: sdio@0x3f1b0000 {
+ max-frequency = <48000000>;
+ status = "okay";
+ };
+
+
};
diff --git a/arch/arm/boot/dts/bcm11351.dtsi b/arch/arm/boot/dts/bcm11351.dtsi
index ad13588..6606b41 100644
--- a/arch/arm/boot/dts/bcm11351.dtsi
+++ b/arch/arm/boot/dts/bcm11351.dtsi
@@ -47,4 +47,33 @@
cache-unified;
cache-level = <2>;
};
+
+ sdio0: sdio@0x3f180000 {
+ compatible = "bcm,kona-sdhci";
+ reg = <0x3f180000 0x10000>;
+ interrupts = <0x0 77 0x4>;
+ status = "disabled";
+ };
+
+ sdio1: sdio@0x3f190000 {
+ compatible = "bcm,kona-sdhci";
+ reg = <0x3f190000 0x10000>;
+ interrupts = <0x0 76 0x4>;
+ status = "disabled";
+ };
+
+ sdio2: sdio@0x3f1a0000 {
+ compatible = "bcm,kona-sdhci";
+ reg = <0x3f1a0000 0x10000>;
+ interrupts = <0x0 74 0x4>;
+ status = "disabled";
+ };
+
+ sdio3: sdio@0x3f1b0000 {
+ compatible = "bcm,kona-sdhci";
+ reg = <0x3f1b0000 0x10000>;
+ interrupts = <0x0 73 0x4>;
+ status = "disabled";
+ };
+
};
diff --git a/arch/arm/configs/bcm_defconfig b/arch/arm/configs/bcm_defconfig
index e3bf2d6..65edf6d 100644
--- a/arch/arm/configs/bcm_defconfig
+++ b/arch/arm/configs/bcm_defconfig
@@ -78,6 +78,13 @@ CONFIG_BACKLIGHT_LCD_SUPPORT=y
CONFIG_LCD_CLASS_DEVICE=y
CONFIG_BACKLIGHT_CLASS_DEVICE=y
# CONFIG_USB_SUPPORT is not set
+CONFIG_MMC=y
+CONFIG_MMC_UNSAFE_RESUME=y
+CONFIG_MMC_BLOCK_MINORS=32
+CONFIG_MMC_TEST=y
+CONFIG_MMC_SDHCI=y
+CONFIG_MMC_SDHCI_PLTFM=y
+CONFIG_MMC_SDHCI_BCM_KONA=y
CONFIG_NEW_LEDS=y
CONFIG_LEDS_CLASS=y
CONFIG_LEDS_TRIGGERS=y
diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index d88219e..e067c5a 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -238,6 +238,16 @@ config MMC_SDHCI_S3C_DMA

YMMV.

+config MMC_SDHCI_BCM_KONA
+ tristate "SDHCI support on Broadcom KONA platform"
+ depends on ARCH_BCM && MMC_SDHCI_PLTFM
+ help
+ This selects the Broadcom Kona Secure Digital Host Controller
+ Interface(SDHCI) support.
+ This is used in Broadcom mobile SoCs.
+
+ If you have a controller with this interface, say Y or M here.
+
config MMC_SDHCI_BCM2835
tristate "SDHCI platform support for the BCM2835 SD/MMC Controller"
depends on ARCH_BCM2835
diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index c380e3c..a9f582b 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_MMC_SDHCI_DOVE) += sdhci-dove.o
obj-$(CONFIG_MMC_SDHCI_TEGRA) += sdhci-tegra.o
obj-$(CONFIG_MMC_SDHCI_OF_ESDHC) += sdhci-of-esdhc.o
obj-$(CONFIG_MMC_SDHCI_OF_HLWD) += sdhci-of-hlwd.o
+obj-$(CONFIG_MMC_SDHCI_BCM_KONA) += sdhci-bcm-kona.o
obj-$(CONFIG_MMC_SDHCI_BCM2835) += sdhci-bcm2835.o

ifeq ($(CONFIG_CB710_DEBUG),y)
diff --git a/drivers/mmc/host/sdhci-bcm-kona.c b/drivers/mmc/host/sdhci-bcm-kona.c
new file mode 100644
index 0000000..27188b9
--- /dev/null
+++ b/drivers/mmc/host/sdhci-bcm-kona.c
@@ -0,0 +1,486 @@
+/*
+ * Copyright (C) 2013 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/highmem.h>
+#include <linux/platform_device.h>
+#include <linux/mmc/host.h>
+#include <linux/io.h>
+#include <linux/gpio.h>
+#include <linux/clk.h>
+#include <linux/regulator/consumer.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/version.h>
+
+#include "sdhci-pltfm.h"
+#include "sdhci.h"
+
+#define SDHCI_SOFT_RESET 0x01000000
+#define KONA_SDHOST_CORECTRL 0x8000
+#define KONA_SDHOST_CD_PINCTRL 0x00000008
+#define KONA_SDHOST_STOP_HCLK 0x00000004
+#define KONA_SDHOST_RESET 0x00000002
+#define KONA_SDHOST_EN 0x00000001
+
+#define KONA_SDHOST_CORESTAT 0x8004
+#define KONA_SDHOST_WP 0x00000002
+#define KONA_SDHOST_CD_SW 0x00000001
+
+#define KONA_SDHOST_COREIMR 0x8008
+#define KONA_SDHOST_IP 0x00000001
+
+#define KONA_SDHOST_COREISR 0x800C
+#define KONA_SDHOST_COREIMSR 0x8010
+#define KONA_SDHOST_COREDBG1 0x8014
+#define KONA_SDHOST_COREGPO_MASK 0x8018
+
+#define SD_DETECT_GPIO_DEBOUNCE_128MS 128
+
+#define KONA_MMC_AUTOSUSPEND_DELAY (50)
+
+struct sdhci_bcm_kona_cfg {
+ unsigned int max_freq;
+ int is_8bit;
+ int irq;
+ int cd_gpio;
+ int wp_gpio;
+ int non_removable;
+};
+
+struct sdhci_bcm_kona_dev {
+ struct sdhci_bcm_kona_cfg *cfg;
+ struct device *dev;
+ struct sdhci_host *host;
+ struct clk *peri_clk;
+ struct clk *sleep_clk;
+};
+
+
+static int sdhci_bcm_kona_sd_reset(struct sdhci_host *host)
+{
+ unsigned int val;
+ unsigned long timeout;
+
+ /* This timeout should be sufficent for core to reset */
+ timeout = jiffies + msecs_to_jiffies(100);
+
+ /* reset the host using the top level reset */
+ val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
+ val |= KONA_SDHOST_RESET;
+ sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
+
+ while (!(sdhci_readl(host, KONA_SDHOST_CORECTRL) & KONA_SDHOST_RESET)) {
+ if (time_is_before_jiffies(timeout)) {
+ pr_err("Error: sd host is stuck in reset!!!\n");
+ return -EFAULT;
+ }
+ }
+
+ /* bring the host out of reset */
+ val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
+ val &= ~KONA_SDHOST_RESET;
+
+ /*
+ * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
+ * Back-to-Back writes to same register needs delay when SD bus clock
+ * is very low w.r.t AHB clock, mainly during boot-time and during card
+ * insert-removal.
+ */
+ udelay(1000);
+ sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
+
+ return 0;
+}
+
+static void sdhci_bcm_kona_sd_init(struct sdhci_host *host)
+{
+ unsigned int val;
+
+ /* enable the interrupt from the IP core */
+ val = sdhci_readl(host, KONA_SDHOST_COREIMR);
+ val |= KONA_SDHOST_IP;
+ sdhci_writel(host, val, KONA_SDHOST_COREIMR);
+
+ /* Enable the AHB clock gating module to the host */
+ val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
+ val |= KONA_SDHOST_EN;
+
+ /*
+ * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
+ * Back-to-Back writes to same register needs delay when SD bus clock
+ * is very low w.r.t AHB clock, mainly during boot-time and during card
+ * insert-removal.
+ */
+ udelay(1000);
+ sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
+}
+
+/*
+ * Software emulation of the SD card insertion/removal. Set insert=1 for insert
+ * and insert=0 for removal. The card detection is done by GPIO. For Broadcom
+ * IP to function properly the bit 0 of CORESTAT register needs to be set/reset
+ * to generate the CD IRQ handled in sdhci.c which schedules card_tasklet.
+ */
+static int sdhci_bcm_kona_sd_card_emulate(struct sdhci_host *host, int insert)
+{
+ struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
+ struct sdhci_bcm_kona_dev *kona_dev = pltfm_priv->priv;
+ u32 val;
+ unsigned long flags;
+
+ /* this function can be called from various contexts including ISR */
+ spin_lock_irqsave(&host->lock, flags);
+ /* Ensure SD bus scanning to detect media change */
+ host->mmc->rescan_disable = 0;
+
+ /*
+ * Back-to-Back register write needs a delay of min 10uS.
+ * Back-to-Back writes to same register needs delay when SD bus clock
+ * is very low w.r.t AHB clock, mainly during boot-time and during card
+ * insert-removal.
+ * We keep 20uS
+ */
+ udelay(20);
+ val = sdhci_readl(host, KONA_SDHOST_CORESTAT);
+
+ if (insert) {
+ if (kona_dev->cfg->wp_gpio >= 0) {
+ int wp_status = gpio_get_value(kona_dev->cfg->wp_gpio);
+
+ if (wp_status)
+ val |= KONA_SDHOST_WP;
+ else
+ val &= ~KONA_SDHOST_WP;
+ }
+
+ val |= KONA_SDHOST_CD_SW;
+ sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
+ } else {
+ val &= ~KONA_SDHOST_CD_SW;
+ sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
+ }
+ spin_unlock_irqrestore(&host->lock, flags);
+
+ return 0;
+}
+
+/*
+ * SD card detection interrupt handler
+ */
+static irqreturn_t sdhci_bcm_kona_pltfm_cd_interrupt(int irq, void *host)
+{
+ struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
+ struct sdhci_bcm_kona_dev *kona_dev = pltfm_priv->priv;
+
+ if (gpio_get_value_cansleep(kona_dev->cfg->cd_gpio) == 0) {
+ pr_debug("card inserted\n");
+ sdhci_bcm_kona_sd_card_emulate(host, 1);
+ } else {
+ pr_debug("card removed\n");
+ sdhci_bcm_kona_sd_card_emulate(host, 0);
+ }
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * Get the base clock. Use central clock source for now. Not sure if different
+ * clock speed to each dev is allowed
+ */
+static unsigned int sdhci_bcm_kona_get_max_clk(struct sdhci_host *host)
+{
+ struct sdhci_bcm_kona_dev *kona_dev;
+ struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
+ kona_dev = pltfm_priv->priv;
+
+ return kona_dev->cfg->max_freq;
+}
+
+static unsigned int sdhci_bcm_kona_get_timeout_clock(struct sdhci_host *host)
+{
+ return sdhci_bcm_kona_get_max_clk(host);
+}
+
+static void sdhci_bcm_kona_init_74_clocks(struct sdhci_host *host,
+ u8 power_mode)
+{
+ if (power_mode == MMC_POWER_OFF)
+ return;
+ else
+ mdelay(10);
+}
+
+static struct sdhci_ops sdhci_bcm_kona_ops = {
+ .get_max_clock = sdhci_bcm_kona_get_max_clk,
+ .get_timeout_clock = sdhci_bcm_kona_get_timeout_clock,
+ .platform_send_init_74_clocks = sdhci_bcm_kona_init_74_clocks,
+};
+
+static struct sdhci_pltfm_data sdhci_pltfm_data_kona = {
+ .ops = &sdhci_bcm_kona_ops,
+ .quirks = SDHCI_QUIRK_NO_CARD_NO_RESET |
+ SDHCI_QUIRK_BROKEN_TIMEOUT_VAL | SDHCI_QUIRK_32BIT_DMA_ADDR |
+ SDHCI_QUIRK_32BIT_DMA_SIZE | SDHCI_QUIRK_32BIT_ADMA_SIZE |
+ SDHCI_QUIRK_FORCE_BLK_SZ_2048 |
+ SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
+};
+
+static const struct of_device_id sdhci_bcm_kona_of_match[] __initdata = {
+ { .compatible = "bcm,kona-sdhci", .data = &sdhci_pltfm_data_kona },
+ {}
+};
+MODULE_DEVICE_TABLE(of, sdhci_bcm_kona_of_match);
+
+static struct sdhci_bcm_kona_cfg * __init sdhci_bcm_kona_parse_dt(
+ struct platform_device *pdev)
+{
+ struct sdhci_bcm_kona_cfg *cfg;
+ struct device_node *np = pdev->dev.of_node;
+ u32 temp;
+
+ if (!np)
+ return NULL;
+
+ cfg = devm_kzalloc(&pdev->dev, sizeof(*cfg), GFP_KERNEL);
+ if (!cfg) {
+ dev_err(&pdev->dev, "Can't allocate platform cfg\n");
+ return NULL;
+ }
+
+ cfg->cd_gpio = of_get_named_gpio(np, "cd-gpios", 0);
+ cfg->wp_gpio = of_get_named_gpio(np, "wp-gpios", 0);
+ if (of_get_property(np, "non-removable", NULL))
+ cfg->non_removable = 1;
+
+ if (of_property_read_u32(np, "bus-width", &temp) == 0 && temp == 8)
+ cfg->is_8bit = 1;
+
+ if (of_property_read_u32(np, "max-frequency", &cfg->max_freq)) {
+ dev_err(&pdev->dev, "Missing max-freq for SDHCI cfg\n");
+ return NULL;
+ }
+ return cfg;
+}
+
+static int __init sdhci_bcm_kona_probe(struct platform_device *pdev)
+{
+ const struct of_device_id *match;
+ struct sdhci_bcm_kona_cfg *kona_cfg = NULL;
+ const struct sdhci_pltfm_data *plat_data;
+ struct sdhci_bcm_kona_dev *kona_dev = NULL;
+ struct sdhci_pltfm_host *pltfm_priv;
+ struct device *dev = &pdev->dev;
+ struct sdhci_host *host;
+ int ret;
+ unsigned int irq;
+ ret = 0;
+
+ match = of_match_device(sdhci_bcm_kona_of_match, &pdev->dev);
+ if (!match)
+ plat_data = &sdhci_pltfm_data_kona;
+ else
+ plat_data = match->data;
+
+ host = sdhci_pltfm_init(pdev, (struct sdhci_pltfm_data *)plat_data);
+ if (IS_ERR(host))
+ return PTR_ERR(host);
+
+ kona_cfg = dev->platform_data;
+ if (!kona_cfg)
+ kona_cfg = sdhci_bcm_kona_parse_dt(pdev);
+
+ if (!kona_cfg) {
+ ret = -ENXIO;
+ goto err_pltfm_free;
+ }
+
+ dev_dbg(dev, "%s: inited. IOADDR=%p\n", __func__, host->ioaddr);
+
+ pltfm_priv = sdhci_priv(host);
+
+ kona_dev = devm_kzalloc(dev, sizeof(*kona_dev), GFP_KERNEL);
+ if (!kona_dev) {
+ dev_err(dev, "Can't allocate kona_dev\n");
+ ret = -ENOMEM;
+ goto err_pltfm_free;
+ }
+ kona_dev->cfg = kona_cfg;
+ kona_dev->dev = dev;
+ pltfm_priv->priv = kona_dev;
+
+ dev_dbg(dev, "non-removable=%c\n",
+ (kona_cfg->non_removable) ? 'Y' : 'N');
+ dev_dbg(dev, "cd_gpio %d, wp_gpio %d\n", kona_cfg->cd_gpio,
+ kona_cfg->wp_gpio);
+
+ if (kona_cfg->non_removable) {
+ host->mmc->caps |= MMC_CAP_NONREMOVABLE;
+ host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
+ }
+
+ dev_dbg(dev, "is_8bit=%c\n", (kona_cfg->is_8bit) ? 'Y' : 'N');
+ if (kona_cfg->is_8bit)
+ host->mmc->caps |= MMC_CAP_8_BIT_DATA;
+
+ ret = sdhci_bcm_kona_sd_reset(host);
+ if (ret)
+ goto err_pltfm_free;
+
+ sdhci_bcm_kona_sd_init(host);
+
+ ret = sdhci_add_host(host);
+ if (ret) {
+ dev_err(dev, "Failed sdhci_add_host\n");
+ goto err_reset;
+ }
+
+ /* if device is eMMC, emulate card insert right here */
+ if (kona_cfg->non_removable) {
+ ret = sdhci_bcm_kona_sd_card_emulate(host, 1);
+ if (ret) {
+ dev_err(dev,
+ "unable to emulate card insertion\n");
+ goto err_remove_host;
+ }
+ } else if (kona_dev->cfg->cd_gpio >= 0) {
+ ret = devm_gpio_request(dev, kona_dev->cfg->cd_gpio, "sdio cd");
+ if (ret < 0) {
+ dev_err(kona_dev->dev,
+ "Unable to request GPIO pin %d\n",
+ kona_dev->cfg->cd_gpio);
+ goto err_remove_host;
+ }
+
+ gpio_direction_input(kona_dev->cfg->cd_gpio);
+
+ /* Set debounce for SD Card detect to maximum value (128ms)
+ *
+ * NOTE-1: If gpio_set_debounce() returns error we still
+ * continue with the default debounce value set. Another reason
+ * for doing this is that on rhea-ray boards the SD Detect GPIO
+ * is on GPIO Expander and gpio_set_debounce() will return error
+ * and if we return error from here, then probe() would fail and
+ * SD detection would always fail.
+ *
+ * NOTE-2: We also give a msleep() of the "debounce" time here
+ * so that we give enough time for the debounce to stabilize
+ * before we read the gpio value in gpio_get_value_cansleep().
+ */
+ ret = gpio_set_debounce(kona_dev->cfg->cd_gpio,
+ (SD_DETECT_GPIO_DEBOUNCE_128MS * 1000));
+ if (ret < 0) {
+ dev_err(kona_dev->dev,
+ "%s: gpio set debounce failed."
+ "default debounce value assumed\n", __func__);
+ }
+
+ /* Sleep for 128ms to allow debounce to stabilize */
+ msleep(SD_DETECT_GPIO_DEBOUNCE_128MS);
+ /* request irq for cd_gpio after the gpio debounce is
+ * stabilized, otherwise, some bogus gpio interrupts might be
+ * triggered.
+ */
+ irq = gpio_to_irq(kona_dev->cfg->cd_gpio);
+ ret = devm_request_threaded_irq(dev,
+ irq,
+ NULL,
+ sdhci_bcm_kona_pltfm_cd_interrupt,
+ IRQF_TRIGGER_FALLING|
+ IRQF_TRIGGER_RISING |
+ IRQF_ONESHOT |
+ IRQF_NO_SUSPEND, "sdio cd", host);
+ if (ret) {
+ dev_err(kona_dev->dev,
+ "Unable to request card detection irq=%d"
+ " for gpio=%d ret=%d\n",
+ gpio_to_irq(kona_dev->cfg->cd_gpio),
+ kona_dev->cfg->cd_gpio, ret);
+ goto err_remove_host;
+ }
+ if (kona_dev->cfg->wp_gpio >= 0) {
+ ret = devm_gpio_request(dev,
+ kona_dev->cfg->wp_gpio, "sdio wp");
+ if (ret < 0) {
+ dev_err(&pdev->dev,
+ "Unable to request WP pin %d\n",
+ kona_dev->cfg->wp_gpio);
+ kona_dev->cfg->wp_gpio = -1;
+ } else {
+ gpio_direction_input(kona_dev->cfg->wp_gpio);
+ }
+ }
+
+ /*
+ * Since the card detection GPIO interrupt is configured to be
+ * edge sensitive, check the initial GPIO value here, emulate
+ * only if the card is present
+ */
+ if (gpio_get_value_cansleep(kona_dev->cfg->cd_gpio) == 0)
+ sdhci_bcm_kona_sd_card_emulate(host, 1);
+ }
+
+ dev_dbg(dev, "initialized properly\n");
+ return 0;
+
+err_remove_host:
+ sdhci_remove_host(host, 0);
+
+err_reset:
+ sdhci_bcm_kona_sd_reset(host);
+
+err_pltfm_free:
+ sdhci_pltfm_free(pdev);
+
+ dev_err(dev, "Probing of sdhci-pltfm failed: %d\n", ret);
+ return ret;
+}
+
+static int __exit sdhci_bcm_kona_remove(struct platform_device *pdev)
+{
+ struct sdhci_host *host = platform_get_drvdata(pdev);
+ struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+ struct sdhci_bcm_kona_dev *kona_dev = pltfm_host->priv;
+ int dead;
+ u32 scratch;
+
+ dead = 0;
+ scratch = readl(host->ioaddr + SDHCI_INT_STATUS);
+ if (scratch == (u32)-1)
+ dead = 1;
+ sdhci_remove_host(host, dead);
+
+ sdhci_free_host(host);
+
+ return 0;
+}
+
+static struct platform_driver sdhci_bcm_kona_driver = {
+ .driver = {
+ .name = "sdhci-kona",
+ .owner = THIS_MODULE,
+ .pm = SDHCI_PLTFM_PMOPS,
+ .of_match_table = of_match_ptr(sdhci_bcm_kona_of_match),
+ },
+ .probe = sdhci_bcm_kona_probe,
+ .remove = __exit_p(sdhci_bcm_kona_remove),
+};
+module_platform_driver(sdhci_bcm_kona_driver);
+
+MODULE_DESCRIPTION("SDHCI driver for Broadcom Kona platform");
+MODULE_AUTHOR("Broadcom");
+MODULE_LICENSE("GPL v2");
+
--
1.7.10.4

2013-05-09 12:39:39

by Jean-Christophe PLAGNIOL-VILLARD

[permalink] [raw]

Subject: Re: [PATCH] ARM: mmc: bcm281xx SDHCI driver

On 22:55 Wed 08 May , Christian Daudt wrote:
> Add SDHCI driver for the Broadcom 281xx SoCs. Also
> add bindings for it into bcm281xx dts files.
> Still missing:
> - power managemement

split the dts/dtsi in an other patch
>
> Signed-off-by: Christian Daudt <[email protected]>
>
> diff --git a/Documentation/devicetree/bindings/mmc/bcm,kona-sdhci.txt b/Documentation/devicetree/bindings/mmc/bcm,kona-sdhci.txt
> new file mode 100644
> index 0000000..ad1c4bd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mmc/bcm,kona-sdhci.txt
> @@ -0,0 +1,16 @@
> +Broadcom BCM281xx SDHCI driver
> +
> +This file documents differences between the core properties in mmc.txt
> +and the properties in the bcm281xx driver.
> +
> +Required properties:
> +- compatible : Should be "bcm,kona-sdhci"
> +
> +Example:
> +
> +sdio2: sdio@0x3f1a0000 {
> + compatible = "bcm,kona-sdhci";
> + reg = <0x3f1a0000 0x10000>;
> + interrupts = <0x0 74 0x4>;
> +};
> +
> diff --git a/arch/arm/boot/dts/bcm11351-brt.dts b/arch/arm/boot/dts/bcm11351-brt.dts
> index 248067c..9ae3404 100644
> --- a/arch/arm/boot/dts/bcm11351-brt.dts
> +++ b/arch/arm/boot/dts/bcm11351-brt.dts
> @@ -27,4 +27,21 @@
> status = "okay";
> };
>
> + sdio0: sdio@0x3f180000 {
> + max-frequency = <48000000>;
> + status = "okay";
> + };
> +
> + sdio1: sdio@0x3f190000 {
> + non-removable;
> + max-frequency = <48000000>;
> + status = "okay";
> + };
> +
> + sdio3: sdio@0x3f1b0000 {
> + max-frequency = <48000000>;
> + status = "okay";
> + };
> +
> +
> };
> diff --git a/arch/arm/boot/dts/bcm11351.dtsi b/arch/arm/boot/dts/bcm11351.dtsi
> index ad13588..6606b41 100644
> --- a/arch/arm/boot/dts/bcm11351.dtsi
> +++ b/arch/arm/boot/dts/bcm11351.dtsi
> @@ -47,4 +47,33 @@
> cache-unified;
> cache-level = <2>;
> };
> +
> + sdio0: sdio@0x3f180000 {
> + compatible = "bcm,kona-sdhci";
> + reg = <0x3f180000 0x10000>;
> + interrupts = <0x0 77 0x4>;
> + status = "disabled";
> + };
> +
> + sdio1: sdio@0x3f190000 {
> + compatible = "bcm,kona-sdhci";
> + reg = <0x3f190000 0x10000>;
> + interrupts = <0x0 76 0x4>;
> + status = "disabled";
> + };
> +
> + sdio2: sdio@0x3f1a0000 {
> + compatible = "bcm,kona-sdhci";
> + reg = <0x3f1a0000 0x10000>;
> + interrupts = <0x0 74 0x4>;
> + status = "disabled";
> + };
> +
> + sdio3: sdio@0x3f1b0000 {
> + compatible = "bcm,kona-sdhci";
> + reg = <0x3f1b0000 0x10000>;
> + interrupts = <0x0 73 0x4>;
> + status = "disabled";
> + };
> +
> };
> diff --git a/arch/arm/configs/bcm_defconfig b/arch/arm/configs/bcm_defconfig
> index e3bf2d6..65edf6d 100644
> --- a/arch/arm/configs/bcm_defconfig
> +++ b/arch/arm/configs/bcm_defconfig
> @@ -78,6 +78,13 @@ CONFIG_BACKLIGHT_LCD_SUPPORT=y
> CONFIG_LCD_CLASS_DEVICE=y
> CONFIG_BACKLIGHT_CLASS_DEVICE=y
> # CONFIG_USB_SUPPORT is not set
> +CONFIG_MMC=y
> +CONFIG_MMC_UNSAFE_RESUME=y
> +CONFIG_MMC_BLOCK_MINORS=32
> +CONFIG_MMC_TEST=y
> +CONFIG_MMC_SDHCI=y
> +CONFIG_MMC_SDHCI_PLTFM=y
> +CONFIG_MMC_SDHCI_BCM_KONA=y
> CONFIG_NEW_LEDS=y
> CONFIG_LEDS_CLASS=y
> CONFIG_LEDS_TRIGGERS=y
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index d88219e..e067c5a 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -238,6 +238,16 @@ config MMC_SDHCI_S3C_DMA
>
> YMMV.
>
> +config MMC_SDHCI_BCM_KONA
> + tristate "SDHCI support on Broadcom KONA platform"
> + depends on ARCH_BCM && MMC_SDHCI_PLTFM
select MMC_SDHCI_PLTFM
will be better
> + help
> + This selects the Broadcom Kona Secure Digital Host Controller
> + Interface(SDHCI) support.
> + This is used in Broadcom mobile SoCs.
> +
> + If you have a controller with this interface, say Y or M here.
> +
> config MMC_SDHCI_BCM2835
> tristate "SDHCI platform support for the BCM2835 SD/MMC Controller"
> depends on ARCH_BCM2835
> diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
> index c380e3c..a9f582b 100644
> --- a/drivers/mmc/host/Makefile
> +++ b/drivers/mmc/host/Makefile
> @@ -59,6 +59,7 @@ obj-$(CONFIG_MMC_SDHCI_DOVE) += sdhci-dove.o
> obj-$(CONFIG_MMC_SDHCI_TEGRA) += sdhci-tegra.o
> obj-$(CONFIG_MMC_SDHCI_OF_ESDHC) += sdhci-of-esdhc.o
> obj-$(CONFIG_MMC_SDHCI_OF_HLWD) += sdhci-of-hlwd.o
> +obj-$(CONFIG_MMC_SDHCI_BCM_KONA) += sdhci-bcm-kona.o
> obj-$(CONFIG_MMC_SDHCI_BCM2835) += sdhci-bcm2835.o
>
> ifeq ($(CONFIG_CB710_DEBUG),y)
> diff --git a/drivers/mmc/host/sdhci-bcm-kona.c b/drivers/mmc/host/sdhci-bcm-kona.c
> new file mode 100644
> index 0000000..27188b9
> --- /dev/null
> +++ b/drivers/mmc/host/sdhci-bcm-kona.c
> @@ -0,0 +1,486 @@
> +/*
> + * Copyright (C) 2013 Broadcom Corporation
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation version 2.
> + *
> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
> + * kind, whether express or implied; without even the implied warranty
> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/delay.h>
> +#include <linux/highmem.h>
> +#include <linux/platform_device.h>
> +#include <linux/mmc/host.h>
> +#include <linux/io.h>
> +#include <linux/gpio.h>
> +#include <linux/clk.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_gpio.h>
> +#include <linux/version.h>
> +
> +#include "sdhci-pltfm.h"
> +#include "sdhci.h"
> +
> +#define SDHCI_SOFT_RESET 0x01000000
> +#define KONA_SDHOST_CORECTRL 0x8000
> +#define KONA_SDHOST_CD_PINCTRL 0x00000008
> +#define KONA_SDHOST_STOP_HCLK 0x00000004
> +#define KONA_SDHOST_RESET 0x00000002
> +#define KONA_SDHOST_EN 0x00000001
> +
> +#define KONA_SDHOST_CORESTAT 0x8004
> +#define KONA_SDHOST_WP 0x00000002
> +#define KONA_SDHOST_CD_SW 0x00000001
> +
> +#define KONA_SDHOST_COREIMR 0x8008
> +#define KONA_SDHOST_IP 0x00000001
> +
> +#define KONA_SDHOST_COREISR 0x800C
> +#define KONA_SDHOST_COREIMSR 0x8010
> +#define KONA_SDHOST_COREDBG1 0x8014
> +#define KONA_SDHOST_COREGPO_MASK 0x8018
> +
> +#define SD_DETECT_GPIO_DEBOUNCE_128MS 128
> +
> +#define KONA_MMC_AUTOSUSPEND_DELAY (50)
> +
> +struct sdhci_bcm_kona_cfg {
> + unsigned int max_freq;
> + int is_8bit;
> + int irq;
> + int cd_gpio;
> + int wp_gpio;
> + int non_removable;
> +};
> +
> +struct sdhci_bcm_kona_dev {
> + struct sdhci_bcm_kona_cfg *cfg;
> + struct device *dev;
> + struct sdhci_host *host;
> + struct clk *peri_clk;
> + struct clk *sleep_clk;
> +};
> +
> +
> +static int sdhci_bcm_kona_sd_reset(struct sdhci_host *host)
> +{
> + unsigned int val;
> + unsigned long timeout;
> +
> + /* This timeout should be sufficent for core to reset */
> + timeout = jiffies + msecs_to_jiffies(100);
> +
> + /* reset the host using the top level reset */
> + val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
> + val |= KONA_SDHOST_RESET;
> + sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
> +
> + while (!(sdhci_readl(host, KONA_SDHOST_CORECTRL) & KONA_SDHOST_RESET)) {
> + if (time_is_before_jiffies(timeout)) {
> + pr_err("Error: sd host is stuck in reset!!!\n");
> + return -EFAULT;
> + }
> + }
> +
> + /* bring the host out of reset */
> + val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
> + val &= ~KONA_SDHOST_RESET;
> +
> + /*
> + * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
> + * Back-to-Back writes to same register needs delay when SD bus clock
> + * is very low w.r.t AHB clock, mainly during boot-time and during card
> + * insert-removal.
> + */
> + udelay(1000);
really a udelay of 1ms
> + sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
> +
> + return 0;
> +}
> +
> +static void sdhci_bcm_kona_sd_init(struct sdhci_host *host)
> +{
> + unsigned int val;
> +
> + /* enable the interrupt from the IP core */
> + val = sdhci_readl(host, KONA_SDHOST_COREIMR);
> + val |= KONA_SDHOST_IP;
> + sdhci_writel(host, val, KONA_SDHOST_COREIMR);
> +
> + /* Enable the AHB clock gating module to the host */
> + val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
> + val |= KONA_SDHOST_EN;
> +
> + /*
> + * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
> + * Back-to-Back writes to same register needs delay when SD bus clock
> + * is very low w.r.t AHB clock, mainly during boot-time and during card
> + * insert-removal.
> + */
> + udelay(1000);
ditto
> + sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
> +}
> +
> +/*
> + * Software emulation of the SD card insertion/removal. Set insert=1 for insert
> + * and insert=0 for removal. The card detection is done by GPIO. For Broadcom
> + * IP to function properly the bit 0 of CORESTAT register needs to be set/reset
> + * to generate the CD IRQ handled in sdhci.c which schedules card_tasklet.
> + */
> +static int sdhci_bcm_kona_sd_card_emulate(struct sdhci_host *host, int insert)
> +{
> + struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
> + struct sdhci_bcm_kona_dev *kona_dev = pltfm_priv->priv;
> + u32 val;
> + unsigned long flags;
> +
> + /* this function can be called from various contexts including ISR */
> + spin_lock_irqsave(&host->lock, flags);
> + /* Ensure SD bus scanning to detect media change */
> + host->mmc->rescan_disable = 0;
> +
> + /*
> + * Back-to-Back register write needs a delay of min 10uS.
> + * Back-to-Back writes to same register needs delay when SD bus clock
> + * is very low w.r.t AHB clock, mainly during boot-time and during card
> + * insert-removal.
> + * We keep 20uS
> + */
> + udelay(20);
> + val = sdhci_readl(host, KONA_SDHOST_CORESTAT);
> +
> + if (insert) {
> + if (kona_dev->cfg->wp_gpio >= 0) {
gpio_is_valid
> + int wp_status = gpio_get_value(kona_dev->cfg->wp_gpio);
> +
> + if (wp_status)
> + val |= KONA_SDHOST_WP;
> + else
> + val &= ~KONA_SDHOST_WP;
> + }
> +
> + val |= KONA_SDHOST_CD_SW;
> + sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
> + } else {
> + val &= ~KONA_SDHOST_CD_SW;
> + sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
> + }
> + spin_unlock_irqrestore(&host->lock, flags);
> +
> + return 0;
> +}
> +
> +/*
> + * SD card detection interrupt handler
> + */
> +static irqreturn_t sdhci_bcm_kona_pltfm_cd_interrupt(int irq, void *host)
> +{
> + struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
> + struct sdhci_bcm_kona_dev *kona_dev = pltfm_priv->priv;
> +
> + if (gpio_get_value_cansleep(kona_dev->cfg->cd_gpio) == 0) {
> + pr_debug("card inserted\n");
dev_dbg
> + sdhci_bcm_kona_sd_card_emulate(host, 1);
> + } else {
> + pr_debug("card removed\n");
ditto
> + sdhci_bcm_kona_sd_card_emulate(host, 0);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +/*
> + * Get the base clock. Use central clock source for now. Not sure if different
> + * clock speed to each dev is allowed
> + */
> +static unsigned int sdhci_bcm_kona_get_max_clk(struct sdhci_host *host)
> +{
> + struct sdhci_bcm_kona_dev *kona_dev;
> + struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
> + kona_dev = pltfm_priv->priv;
> +
> + return kona_dev->cfg->max_freq;
> +}
> +
> +static unsigned int sdhci_bcm_kona_get_timeout_clock(struct sdhci_host *host)
> +{
> + return sdhci_bcm_kona_get_max_clk(host);
> +}
> +
> +static void sdhci_bcm_kona_init_74_clocks(struct sdhci_host *host,
> + u8 power_mode)
> +{
> + if (power_mode == MMC_POWER_OFF)
> + return;
> + else
> + mdelay(10);
> +}
> +
> +static struct sdhci_ops sdhci_bcm_kona_ops = {
> + .get_max_clock = sdhci_bcm_kona_get_max_clk,
> + .get_timeout_clock = sdhci_bcm_kona_get_timeout_clock,
> + .platform_send_init_74_clocks = sdhci_bcm_kona_init_74_clocks,
> +};
> +
> +static struct sdhci_pltfm_data sdhci_pltfm_data_kona = {
> + .ops = &sdhci_bcm_kona_ops,
> + .quirks = SDHCI_QUIRK_NO_CARD_NO_RESET |
> + SDHCI_QUIRK_BROKEN_TIMEOUT_VAL | SDHCI_QUIRK_32BIT_DMA_ADDR |
> + SDHCI_QUIRK_32BIT_DMA_SIZE | SDHCI_QUIRK_32BIT_ADMA_SIZE |
> + SDHCI_QUIRK_FORCE_BLK_SZ_2048 |
> + SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
> +};
> +
> +static const struct of_device_id sdhci_bcm_kona_of_match[] __initdata = {
> + { .compatible = "bcm,kona-sdhci", .data = &sdhci_pltfm_data_kona },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, sdhci_bcm_kona_of_match);
> +
> +static struct sdhci_bcm_kona_cfg * __init sdhci_bcm_kona_parse_dt(
> + struct platform_device *pdev)
> +{
> + struct sdhci_bcm_kona_cfg *cfg;
> + struct device_node *np = pdev->dev.of_node;
> + u32 temp;
> +
> + if (!np)
> + return NULL;
> +
> + cfg = devm_kzalloc(&pdev->dev, sizeof(*cfg), GFP_KERNEL);
> + if (!cfg) {
> + dev_err(&pdev->dev, "Can't allocate platform cfg\n");
> + return NULL;
> + }
> +
> + cfg->cd_gpio = of_get_named_gpio(np, "cd-gpios", 0);
> + cfg->wp_gpio = of_get_named_gpio(np, "wp-gpios", 0);
> + if (of_get_property(np, "non-removable", NULL))
> + cfg->non_removable = 1;
use of_property_read_bool
> +
> + if (of_property_read_u32(np, "bus-width", &temp) == 0 && temp == 8)
> + cfg->is_8bit = 1;
> +
> + if (of_property_read_u32(np, "max-frequency", &cfg->max_freq)) {
> + dev_err(&pdev->dev, "Missing max-freq for SDHCI cfg\n");
> + return NULL;
> + }
> + return cfg;
> +}
> +
> +static int __init sdhci_bcm_kona_probe(struct platform_device *pdev)
> +{
> + const struct of_device_id *match;
> + struct sdhci_bcm_kona_cfg *kona_cfg = NULL;
> + const struct sdhci_pltfm_data *plat_data;
> + struct sdhci_bcm_kona_dev *kona_dev = NULL;
> + struct sdhci_pltfm_host *pltfm_priv;
> + struct device *dev = &pdev->dev;
> + struct sdhci_host *host;
> + int ret;
> + unsigned int irq;
> + ret = 0;
> +
> + match = of_match_device(sdhci_bcm_kona_of_match, &pdev->dev);
> + if (!match)
> + plat_data = &sdhci_pltfm_data_kona;
> + else
> + plat_data = match->data;
> +
> + host = sdhci_pltfm_init(pdev, (struct sdhci_pltfm_data *)plat_data);
> + if (IS_ERR(host))
> + return PTR_ERR(host);
> +
> + kona_cfg = dev->platform_data;
> + if (!kona_cfg)
> + kona_cfg = sdhci_bcm_kona_parse_dt(pdev);
> +
> + if (!kona_cfg) {
> + ret = -ENXIO;
> + goto err_pltfm_free;
> + }
> +
> + dev_dbg(dev, "%s: inited. IOADDR=%p\n", __func__, host->ioaddr);
> +
> + pltfm_priv = sdhci_priv(host);
> +
> + kona_dev = devm_kzalloc(dev, sizeof(*kona_dev), GFP_KERNEL);
> + if (!kona_dev) {
> + dev_err(dev, "Can't allocate kona_dev\n");
> + ret = -ENOMEM;
> + goto err_pltfm_free;
> + }
> + kona_dev->cfg = kona_cfg;
> + kona_dev->dev = dev;
> + pltfm_priv->priv = kona_dev;
> +
> + dev_dbg(dev, "non-removable=%c\n",
> + (kona_cfg->non_removable) ? 'Y' : 'N');
> + dev_dbg(dev, "cd_gpio %d, wp_gpio %d\n", kona_cfg->cd_gpio,
> + kona_cfg->wp_gpio);
> +
> + if (kona_cfg->non_removable) {
> + host->mmc->caps |= MMC_CAP_NONREMOVABLE;
> + host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
> + }
> +
> + dev_dbg(dev, "is_8bit=%c\n", (kona_cfg->is_8bit) ? 'Y' : 'N');
> + if (kona_cfg->is_8bit)
> + host->mmc->caps |= MMC_CAP_8_BIT_DATA;
> +
> + ret = sdhci_bcm_kona_sd_reset(host);
> + if (ret)
> + goto err_pltfm_free;
> +
> + sdhci_bcm_kona_sd_init(host);
> +
> + ret = sdhci_add_host(host);
> + if (ret) {
> + dev_err(dev, "Failed sdhci_add_host\n");
> + goto err_reset;
> + }
> +
> + /* if device is eMMC, emulate card insert right here */
> + if (kona_cfg->non_removable) {
> + ret = sdhci_bcm_kona_sd_card_emulate(host, 1);
> + if (ret) {
> + dev_err(dev,
> + "unable to emulate card insertion\n");
> + goto err_remove_host;
> + }
> + } else if (kona_dev->cfg->cd_gpio >= 0) {
> + ret = devm_gpio_request(dev, kona_dev->cfg->cd_gpio, "sdio cd");
> + if (ret < 0) {
> + dev_err(kona_dev->dev,
> + "Unable to request GPIO pin %d\n",
> + kona_dev->cfg->cd_gpio);
> + goto err_remove_host;
> + }
> +
> + gpio_direction_input(kona_dev->cfg->cd_gpio);
> +
> + /* Set debounce for SD Card detect to maximum value (128ms)
> + *
> + * NOTE-1: If gpio_set_debounce() returns error we still
> + * continue with the default debounce value set. Another reason
> + * for doing this is that on rhea-ray boards the SD Detect GPIO
> + * is on GPIO Expander and gpio_set_debounce() will return error
> + * and if we return error from here, then probe() would fail and
> + * SD detection would always fail.
> + *
> + * NOTE-2: We also give a msleep() of the "debounce" time here
> + * so that we give enough time for the debounce to stabilize
> + * before we read the gpio value in gpio_get_value_cansleep().
> + */
> + ret = gpio_set_debounce(kona_dev->cfg->cd_gpio,
> + (SD_DETECT_GPIO_DEBOUNCE_128MS * 1000));
> + if (ret < 0) {
> + dev_err(kona_dev->dev,
> + "%s: gpio set debounce failed."
> + "default debounce value assumed\n", __func__);
> + }
> +
> + /* Sleep for 128ms to allow debounce to stabilize */
> + msleep(SD_DETECT_GPIO_DEBOUNCE_128MS);
> + /* request irq for cd_gpio after the gpio debounce is
> + * stabilized, otherwise, some bogus gpio interrupts might be
> + * triggered.
> + */
> + irq = gpio_to_irq(kona_dev->cfg->cd_gpio);
> + ret = devm_request_threaded_irq(dev,
> + irq,
> + NULL,
> + sdhci_bcm_kona_pltfm_cd_interrupt,
> + IRQF_TRIGGER_FALLING|
> + IRQF_TRIGGER_RISING |
> + IRQF_ONESHOT |
> + IRQF_NO_SUSPEND, "sdio cd", host);
> + if (ret) {
> + dev_err(kona_dev->dev,
> + "Unable to request card detection irq=%d"
> + " for gpio=%d ret=%d\n",
put the sting of the dev_err on one line so we can grep
> + gpio_to_irq(kona_dev->cfg->cd_gpio),
> + kona_dev->cfg->cd_gpio, ret);
> + goto err_remove_host;
> + }
> + if (kona_dev->cfg->wp_gpio >= 0) {
> + ret = devm_gpio_request(dev,
> + kona_dev->cfg->wp_gpio, "sdio wp");
> + if (ret < 0) {
> + dev_err(&pdev->dev,
> + "Unable to request WP pin %d\n",
> + kona_dev->cfg->wp_gpio);
> + kona_dev->cfg->wp_gpio = -1;
> + } else {
> + gpio_direction_input(kona_dev->cfg->wp_gpio);
> + }
> + }
> +
> + /*
> + * Since the card detection GPIO interrupt is configured to be
> + * edge sensitive, check the initial GPIO value here, emulate
> + * only if the card is present
> + */
> + if (gpio_get_value_cansleep(kona_dev->cfg->cd_gpio) == 0)
> + sdhci_bcm_kona_sd_card_emulate(host, 1);
> + }
> +
> + dev_dbg(dev, "initialized properly\n");
> + return 0;
> +
> +err_remove_host:
> + sdhci_remove_host(host, 0);
> +
> +err_reset:
> + sdhci_bcm_kona_sd_reset(host);
> +
> +err_pltfm_free:
> + sdhci_pltfm_free(pdev);
> +
> + dev_err(dev, "Probing of sdhci-pltfm failed: %d\n", ret);
> + return ret;
> +}
> +
> +static int __exit sdhci_bcm_kona_remove(struct platform_device *pdev)
> +{
> + struct sdhci_host *host = platform_get_drvdata(pdev);
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_bcm_kona_dev *kona_dev = pltfm_host->priv;
> + int dead;
> + u32 scratch;
> +
> + dead = 0;
> + scratch = readl(host->ioaddr + SDHCI_INT_STATUS);
> + if (scratch == (u32)-1)
> + dead = 1;
> + sdhci_remove_host(host, dead);
> +
> + sdhci_free_host(host);
> +
> + return 0;
> +}
> +
> +static struct platform_driver sdhci_bcm_kona_driver = {
> + .driver = {
> + .name = "sdhci-kona",
> + .owner = THIS_MODULE,
> + .pm = SDHCI_PLTFM_PMOPS,
> + .of_match_table = of_match_ptr(sdhci_bcm_kona_of_match),
> + },
> + .probe = sdhci_bcm_kona_probe,
> + .remove = __exit_p(sdhci_bcm_kona_remove),
> +};
> +module_platform_driver(sdhci_bcm_kona_driver);
> +
> +MODULE_DESCRIPTION("SDHCI driver for Broadcom Kona platform");
> +MODULE_AUTHOR("Broadcom");
> +MODULE_LICENSE("GPL v2");
> +
> --
> 1.7.10.4
>
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

2013-05-10 08:28:11

by Christian Daudt

[permalink] [raw]

Subject: Re: [PATCH] ARM: mmc: bcm281xx SDHCI driver

Thanks for the feedback.

On 13-05-08 11:35 PM, Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 22:55 Wed 08 May , Christian Daudt wrote:
>> Add SDHCI driver for the Broadcom 281xx SoCs. Also
>> add bindings for it into bcm281xx dts files.
>> Still missing:
>> - power managemement
> split the dts/dtsi in an other patch
ok.
>> Signed-off-by: Christian Daudt <[email protected]>
>>
>> diff --git a/arch/arm/configs/bcm_defconfig b/arch/arm/configs/bcm_defconfig
>> index e3bf2d6..65edf6d 100644
>> --- a/arch/arm/configs/bcm_defconfig
>> +++ b/arch/arm/configs/bcm_defconfig
>> @@ -78,6 +78,13 @@ CONFIG_BACKLIGHT_LCD_SUPPORT=y
>> CONFIG_LCD_CLASS_DEVICE=y
>> CONFIG_BACKLIGHT_CLASS_DEVICE=y
>> # CONFIG_USB_SUPPORT is not set
>> +CONFIG_MMC=y
>> +CONFIG_MMC_UNSAFE_RESUME=y
>> +CONFIG_MMC_BLOCK_MINORS=32
>> +CONFIG_MMC_TEST=y
>> +CONFIG_MMC_SDHCI=y
>> +CONFIG_MMC_SDHCI_PLTFM=y
>> +CONFIG_MMC_SDHCI_BCM_KONA=y
>> CONFIG_NEW_LEDS=y
>> CONFIG_LEDS_CLASS=y
>> CONFIG_LEDS_TRIGGERS=y
>> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
>> index d88219e..e067c5a 100644
>> --- a/drivers/mmc/host/Kconfig
>> +++ b/drivers/mmc/host/Kconfig
>> @@ -238,6 +238,16 @@ config MMC_SDHCI_S3C_DMA
>>
>> YMMV.
>>
>> +config MMC_SDHCI_BCM_KONA
>> + tristate "SDHCI support on Broadcom KONA platform"
>> + depends on ARCH_BCM && MMC_SDHCI_PLTFM
> select MMC_SDHCI_PLTFM
> will be better
Ok - changed it. Why is the select is better than the depends ?
>> +
>> +static int sdhci_bcm_kona_sd_reset(struct sdhci_host *host)
>> +{
>> + unsigned int val;
>> + unsigned long timeout;
>> +
>> + /* This timeout should be sufficent for core to reset */
>> + timeout = jiffies + msecs_to_jiffies(100);
>> +
>> + /* reset the host using the top level reset */
>> + val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
>> + val |= KONA_SDHOST_RESET;
>> + sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
>> +
>> + while (!(sdhci_readl(host, KONA_SDHOST_CORECTRL) & KONA_SDHOST_RESET)) {
>> + if (time_is_before_jiffies(timeout)) {
>> + pr_err("Error: sd host is stuck in reset!!!\n");
>> + return -EFAULT;
>> + }
>> + }
>> +
>> + /* bring the host out of reset */
>> + val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
>> + val &= ~KONA_SDHOST_RESET;
>> +
>> + /*
>> + * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
>> + * Back-to-Back writes to same register needs delay when SD bus clock
>> + * is very low w.r.t AHB clock, mainly during boot-time and during card
>> + * insert-removal.
>> + */
>> + udelay(1000);
> really a udelay of 1ms
I'm trying to clarify on whether this is really necessary but it does
seem that this is the case. I'll send a follow-up patch if I manage to
get confirmation on a smaller safe number.

>> + sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
>> +
>> + return 0;
>> +}
>> +
>> +static void sdhci_bcm_kona_sd_init(struct sdhci_host *host)
>> +{
>> + unsigned int val;
>> +
>> + /* enable the interrupt from the IP core */
>> + val = sdhci_readl(host, KONA_SDHOST_COREIMR);
>> + val |= KONA_SDHOST_IP;
>> + sdhci_writel(host, val, KONA_SDHOST_COREIMR);
>> +
>> + /* Enable the AHB clock gating module to the host */
>> + val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
>> + val |= KONA_SDHOST_EN;
>> +
>> + /*
>> + * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
>> + * Back-to-Back writes to same register needs delay when SD bus clock
>> + * is very low w.r.t AHB clock, mainly during boot-time and during card
>> + * insert-removal.
>> + */
>> + udelay(1000);
> ditto
see above
>> + sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
>> +}
>> +
>> +/*
>> + * Software emulation of the SD card insertion/removal. Set insert=1 for insert
>> + * and insert=0 for removal. The card detection is done by GPIO. For Broadcom
>> + * IP to function properly the bit 0 of CORESTAT register needs to be set/reset
>> + * to generate the CD IRQ handled in sdhci.c which schedules card_tasklet.
>> + */
>> +static int sdhci_bcm_kona_sd_card_emulate(struct sdhci_host *host, int insert)
>> +{
>> + struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
>> + struct sdhci_bcm_kona_dev *kona_dev = pltfm_priv->priv;
>> + u32 val;
>> + unsigned long flags;
>> +
>> + /* this function can be called from various contexts including ISR */
>> + spin_lock_irqsave(&host->lock, flags);
>> + /* Ensure SD bus scanning to detect media change */
>> + host->mmc->rescan_disable = 0;
>> +
>> + /*
>> + * Back-to-Back register write needs a delay of min 10uS.
>> + * Back-to-Back writes to same register needs delay when SD bus clock
>> + * is very low w.r.t AHB clock, mainly during boot-time and during card
>> + * insert-removal.
>> + * We keep 20uS
>> + */
>> + udelay(20);
>> + val = sdhci_readl(host, KONA_SDHOST_CORESTAT);
>> +
>> + if (insert) {
>> + if (kona_dev->cfg->wp_gpio >= 0) {
> gpio_is_valid
done
>> + int wp_status = gpio_get_value(kona_dev->cfg->wp_gpio);
>> +
>> + if (wp_status)
>> + val |= KONA_SDHOST_WP;
>> + else
>> + val &= ~KONA_SDHOST_WP;
>> + }
>> +
>> + val |= KONA_SDHOST_CD_SW;
>> + sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
>> + } else {
>> + val &= ~KONA_SDHOST_CD_SW;
>> + sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
>> + }
>> + spin_unlock_irqrestore(&host->lock, flags);
>> +
>> + return 0;
>> +}
>> +
>> +/*
>> + * SD card detection interrupt handler
>> + */
>> +static irqreturn_t sdhci_bcm_kona_pltfm_cd_interrupt(int irq, void *host)
>> +{
>> + struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
>> + struct sdhci_bcm_kona_dev *kona_dev = pltfm_priv->priv;
>> +
>> + if (gpio_get_value_cansleep(kona_dev->cfg->cd_gpio) == 0) {
>> + pr_debug("card inserted\n");
> dev_dbg
done
>> + sdhci_bcm_kona_sd_card_emulate(host, 1);
>> + } else {
>> + pr_debug("card removed\n");
> ditto
done
>> +static struct sdhci_bcm_kona_cfg * __init sdhci_bcm_kona_parse_dt(
>> + struct platform_device *pdev)
>> +{
>> + struct sdhci_bcm_kona_cfg *cfg;
>> + struct device_node *np = pdev->dev.of_node;
>> + u32 temp;
>> +
>> + if (!np)
>> + return NULL;
>> +
>> + cfg = devm_kzalloc(&pdev->dev, sizeof(*cfg), GFP_KERNEL);
>> + if (!cfg) {
>> + dev_err(&pdev->dev, "Can't allocate platform cfg\n");
>> + return NULL;
>> + }
>> +
>> + cfg->cd_gpio = of_get_named_gpio(np, "cd-gpios", 0);
>> + cfg->wp_gpio = of_get_named_gpio(np, "wp-gpios", 0);
>> + if (of_get_property(np, "non-removable", NULL))
>> + cfg->non_removable = 1;
> use of_property_read_bool
done
>> + /* Sleep for 128ms to allow debounce to stabilize */
>> + msleep(SD_DETECT_GPIO_DEBOUNCE_128MS);
>> + /* request irq for cd_gpio after the gpio debounce is
>> + * stabilized, otherwise, some bogus gpio interrupts might be
>> + * triggered.
>> + */
>> + irq = gpio_to_irq(kona_dev->cfg->cd_gpio);
>> + ret = devm_request_threaded_irq(dev,
>> + irq,
>> + NULL,
>> + sdhci_bcm_kona_pltfm_cd_interrupt,
>> + IRQF_TRIGGER_FALLING|
>> + IRQF_TRIGGER_RISING |
>> + IRQF_ONESHOT |
>> + IRQF_NO_SUSPEND, "sdio cd", host);
>> + if (ret) {
>> + dev_err(kona_dev->dev,
>> + "Unable to request card detection irq=%d"
>> + " for gpio=%d ret=%d\n",
> put the sting of the dev_err on one line so we can grep
merged it into single line

Thanks,
csd

2013-05-10 10:03:39

by Christian Daudt

[permalink] [raw]

Subject: Re: [PATCH] ARM: mmc: bcm281xx SDHCI driver

2013-05-10 10:20:29

by Christian Daudt

[permalink] [raw]

Subject: Re: [PATCH] ARM: mmc: bcm281xx SDHCI driver

2013-05-10 10:33:02

by Jean-Christophe PLAGNIOL-VILLARD

[permalink] [raw]

Subject: Re: [PATCH] ARM: mmc: bcm281xx SDHCI driver

On 00:29 Fri 10 May , Christian Daudt wrote:
> Thanks for the feedback.
>
> On 13-05-08 11:35 PM, Jean-Christophe PLAGNIOL-VILLARD wrote:
> >On 22:55 Wed 08 May , Christian Daudt wrote:
> >>Add SDHCI driver for the Broadcom 281xx SoCs. Also
> >>add bindings for it into bcm281xx dts files.
> >>Still missing:
> >> - power managemement
> >split the dts/dtsi in an other patch
> ok.
> >>Signed-off-by: Christian Daudt <[email protected]>
> >>
> >>diff --git a/arch/arm/configs/bcm_defconfig b/arch/arm/configs/bcm_defconfig
> >>index e3bf2d6..65edf6d 100644
> >>--- a/arch/arm/configs/bcm_defconfig
> >>+++ b/arch/arm/configs/bcm_defconfig
> >>@@ -78,6 +78,13 @@ CONFIG_BACKLIGHT_LCD_SUPPORT=y
> >> CONFIG_LCD_CLASS_DEVICE=y
> >> CONFIG_BACKLIGHT_CLASS_DEVICE=y
> >> # CONFIG_USB_SUPPORT is not set
> >>+CONFIG_MMC=y
> >>+CONFIG_MMC_UNSAFE_RESUME=y
> >>+CONFIG_MMC_BLOCK_MINORS=32
> >>+CONFIG_MMC_TEST=y
> >>+CONFIG_MMC_SDHCI=y
> >>+CONFIG_MMC_SDHCI_PLTFM=y
> >>+CONFIG_MMC_SDHCI_BCM_KONA=y
> >> CONFIG_NEW_LEDS=y
> >> CONFIG_LEDS_CLASS=y
> >> CONFIG_LEDS_TRIGGERS=y
> >>diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> >>index d88219e..e067c5a 100644
> >>--- a/drivers/mmc/host/Kconfig
> >>+++ b/drivers/mmc/host/Kconfig
> >>@@ -238,6 +238,16 @@ config MMC_SDHCI_S3C_DMA
> >> YMMV.
> >>+config MMC_SDHCI_BCM_KONA
> >>+ tristate "SDHCI support on Broadcom KONA platform"
> >>+ depends on ARCH_BCM && MMC_SDHCI_PLTFM
> >select MMC_SDHCI_PLTFM
> >will be better
> Ok - changed it. Why is the select is better than the depends ?
> >>+
> >>+static int sdhci_bcm_kona_sd_reset(struct sdhci_host *host)
> >>+{
> >>+ unsigned int val;
> >>+ unsigned long timeout;
> >>+
> >>+ /* This timeout should be sufficent for core to reset */
> >>+ timeout = jiffies + msecs_to_jiffies(100);
> >>+
> >>+ /* reset the host using the top level reset */
> >>+ val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
> >>+ val |= KONA_SDHOST_RESET;
> >>+ sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
> >>+
> >>+ while (!(sdhci_readl(host, KONA_SDHOST_CORECTRL) & KONA_SDHOST_RESET)) {
> >>+ if (time_is_before_jiffies(timeout)) {
> >>+ pr_err("Error: sd host is stuck in reset!!!\n");
> >>+ return -EFAULT;
> >>+ }
> >>+ }
> >>+
> >>+ /* bring the host out of reset */
> >>+ val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
> >>+ val &= ~KONA_SDHOST_RESET;
> >>+
> >>+ /*
> >>+ * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
> >>+ * Back-to-Back writes to same register needs delay when SD bus clock
> >>+ * is very low w.r.t AHB clock, mainly during boot-time and during card
> >>+ * insert-removal.
> >>+ */
> >>+ udelay(1000);
> >really a udelay of 1ms
> I'm trying to clarify on whether this is really necessary but it
> does seem that this is the case. I'll send a follow-up patch if I
> manage to get confirmation on a smaller safe number.

a smaller delay will be better otherwise a msleep(1)

Best Regards,
J.
>
> >>+ sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
> >>+
> >>+ return 0;
> >>+}
> >>+
> >>+static void sdhci_bcm_kona_sd_init(struct sdhci_host *host)
> >>+{
> >>+ unsigned int val;
> >>+
> >>+ /* enable the interrupt from the IP core */
> >>+ val = sdhci_readl(host, KONA_SDHOST_COREIMR);
> >>+ val |= KONA_SDHOST_IP;
> >>+ sdhci_writel(host, val, KONA_SDHOST_COREIMR);
> >>+
> >>+ /* Enable the AHB clock gating module to the host */
> >>+ val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
> >>+ val |= KONA_SDHOST_EN;
> >>+
> >>+ /*
> >>+ * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
> >>+ * Back-to-Back writes to same register needs delay when SD bus clock
> >>+ * is very low w.r.t AHB clock, mainly during boot-time and during card
> >>+ * insert-removal.
> >>+ */
> >>+ udelay(1000);
> >ditto
> see above
> >>+ sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
> >>+}
> >>+
> >>+/*
> >>+ * Software emulation of the SD card insertion/removal. Set insert=1 for insert
> >>+ * and insert=0 for removal. The card detection is done by GPIO. For Broadcom
> >>+ * IP to function properly the bit 0 of CORESTAT register needs to be set/reset
> >>+ * to generate the CD IRQ handled in sdhci.c which schedules card_tasklet.
> >>+ */
> >>+static int sdhci_bcm_kona_sd_card_emulate(struct sdhci_host *host, int insert)
> >>+{
> >>+ struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
> >>+ struct sdhci_bcm_kona_dev *kona_dev = pltfm_priv->priv;
> >>+ u32 val;
> >>+ unsigned long flags;
> >>+
> >>+ /* this function can be called from various contexts including ISR */
> >>+ spin_lock_irqsave(&host->lock, flags);
> >>+ /* Ensure SD bus scanning to detect media change */
> >>+ host->mmc->rescan_disable = 0;
> >>+
> >>+ /*
> >>+ * Back-to-Back register write needs a delay of min 10uS.
> >>+ * Back-to-Back writes to same register needs delay when SD bus clock
> >>+ * is very low w.r.t AHB clock, mainly during boot-time and during card
> >>+ * insert-removal.
> >>+ * We keep 20uS
> >>+ */
> >>+ udelay(20);
> >>+ val = sdhci_readl(host, KONA_SDHOST_CORESTAT);
> >>+
> >>+ if (insert) {
> >>+ if (kona_dev->cfg->wp_gpio >= 0) {
> >gpio_is_valid
> done
> >>+ int wp_status = gpio_get_value(kona_dev->cfg->wp_gpio);
> >>+
> >>+ if (wp_status)
> >>+ val |= KONA_SDHOST_WP;
> >>+ else
> >>+ val &= ~KONA_SDHOST_WP;
> >>+ }
> >>+
> >>+ val |= KONA_SDHOST_CD_SW;
> >>+ sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
> >>+ } else {
> >>+ val &= ~KONA_SDHOST_CD_SW;
> >>+ sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
> >>+ }
> >>+ spin_unlock_irqrestore(&host->lock, flags);
> >>+
> >>+ return 0;
> >>+}
> >>+
> >>+/*
> >>+ * SD card detection interrupt handler
> >>+ */
> >>+static irqreturn_t sdhci_bcm_kona_pltfm_cd_interrupt(int irq, void *host)
> >>+{
> >>+ struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
> >>+ struct sdhci_bcm_kona_dev *kona_dev = pltfm_priv->priv;
> >>+
> >>+ if (gpio_get_value_cansleep(kona_dev->cfg->cd_gpio) == 0) {
> >>+ pr_debug("card inserted\n");
> >dev_dbg
> done
> >>+ sdhci_bcm_kona_sd_card_emulate(host, 1);
> >>+ } else {
> >>+ pr_debug("card removed\n");
> >ditto
> done
> >>+static struct sdhci_bcm_kona_cfg * __init sdhci_bcm_kona_parse_dt(
> >>+ struct platform_device *pdev)
> >>+{
> >>+ struct sdhci_bcm_kona_cfg *cfg;
> >>+ struct device_node *np = pdev->dev.of_node;
> >>+ u32 temp;
> >>+
> >>+ if (!np)
> >>+ return NULL;
> >>+
> >>+ cfg = devm_kzalloc(&pdev->dev, sizeof(*cfg), GFP_KERNEL);
> >>+ if (!cfg) {
> >>+ dev_err(&pdev->dev, "Can't allocate platform cfg\n");
> >>+ return NULL;
> >>+ }
> >>+
> >>+ cfg->cd_gpio = of_get_named_gpio(np, "cd-gpios", 0);
> >>+ cfg->wp_gpio = of_get_named_gpio(np, "wp-gpios", 0);
> >>+ if (of_get_property(np, "non-removable", NULL))
> >>+ cfg->non_removable = 1;
> >use of_property_read_bool
> done
> >>+ /* Sleep for 128ms to allow debounce to stabilize */
> >>+ msleep(SD_DETECT_GPIO_DEBOUNCE_128MS);
> >>+ /* request irq for cd_gpio after the gpio debounce is
> >>+ * stabilized, otherwise, some bogus gpio interrupts might be
> >>+ * triggered.
> >>+ */
> >>+ irq = gpio_to_irq(kona_dev->cfg->cd_gpio);
> >>+ ret = devm_request_threaded_irq(dev,
> >>+ irq,
> >>+ NULL,
> >>+ sdhci_bcm_kona_pltfm_cd_interrupt,
> >>+ IRQF_TRIGGER_FALLING|
> >>+ IRQF_TRIGGER_RISING |
> >>+ IRQF_ONESHOT |
> >>+ IRQF_NO_SUSPEND, "sdio cd", host);
> >>+ if (ret) {
> >>+ dev_err(kona_dev->dev,
> >>+ "Unable to request card detection irq=%d"
> >>+ " for gpio=%d ret=%d\n",
> >put the sting of the dev_err on one line so we can grep
> merged it into single line
>
>
> Thanks,
> csd
>
>

2013-05-10 15:20:15

by Jean-Christophe PLAGNIOL-VILLARD

[permalink] [raw]

Subject: Re: [PATCH] ARM: mmc: bcm281xx SDHCI driver

2013-05-11 04:28:26

by Stephen Warren

[permalink] [raw]

Subject: Re: [PATCH] ARM: mmc: bcm281xx SDHCI driver

On 05/08/2013 11:55 PM, Christian Daudt wrote:
> Add SDHCI driver for the Broadcom 281xx SoCs. Also
> add bindings for it into bcm281xx dts files.
> Still missing:
> - power managemement

> diff --git a/drivers/mmc/host/sdhci-bcm-kona.c b/drivers/mmc/host/sdhci-bcm-kona.c

> + /*
> + * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
> + * Back-to-Back writes to same register needs delay when SD bus clock
> + * is very low w.r.t AHB clock, mainly during boot-time and during card
> + * insert-removal.
> + */
> + udelay(1000);
> + sdhci_writel(host, val, KONA_SDHOST_CORECTRL);

This sounds very similar to the workaround in
drivers/mmc/host/sdhci-bcm2835.c. Is this the same IP block supported by
that driver? Perhaps not, since bcm2835 apparently needs other WARs such
as always using 32-bit IO and hence needing custom read/write w/b
functions to do read-modify-write which isn't here?