2014-06-25 21:08:44

by Thor Thayer

[permalink] [raw]
Subject: [PATCHv7 0/3] Addition of Altera SDRAM Controller Summary

From: Thor Thayer <[email protected]>

This patch series adds Altera SDRAM EDAC support.

The one sticky issue seems to be the use of "syscon". One register
in the SDRAM controller shares bitfields with different functionality.
In this series the devicetree includes the "syscon" designation
for the SDRAM Controller [patch 1] but the bindings document does not.
This flexibility means future generations of SDRAM controller may
correct this sharing of bitfields without changes to the bindings.

Thor Thayer (3):
devicetree: Addition of the Altera SDRAM Controller.
Add the Altera SDRAM controller bindings and device tree
changes to the Altera SoC project.
devicetree: Addition of the Altera SDRAM EDAC.
Add the Altera SDRAM EDAC bindings and device tree changes
to the Altera SoC project.
edac: altera: Add EDAC support for Altera SoC SDRAM Controller.
This patch adds support for the CycloneV and ArriaV SDRAM
controllers. Correction and reporting of SBEs, Panic on DBEs.

.../bindings/arm/altera/socfpga-sdram-edac.txt | 15 +
.../bindings/arm/altera/socfpga-sdram.txt | 11 +
arch/arm/boot/dts/socfpga.dtsi | 11 +
drivers/edac/Kconfig | 9 +
drivers/edac/Makefile | 2 +
drivers/edac/altera_edac.c | 448 ++++++++++++++++++++
6 files changed, 496 insertions(+)
create mode 100644 Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
create mode 100644 Documentation/devicetree/bindings/arm/altera/socfpga-sdram.txt
create mode 100644 drivers/edac/altera_edac.c

--
1.7.9.5


2014-06-25 21:09:03

by Thor Thayer

[permalink] [raw]
Subject: [PATCHv7 2/3] devicetree: Addition of the Altera SDRAM EDAC.

From: Thor Thayer <[email protected]>

Add the Altera SDRAM EDAC bindings and device tree changes to the Altera SoC project.

Signed-off-by: Thor Thayer <[email protected]>
---
v2: Changes to SoC EDAC source code.

v3: Fix typo in device tree documentation.

v4,v5: No changes - bump version for consistency.

v6: Assign ECC registers in SDRAM controller to EDAC

v7: Fix SDRAM EDAC base address.
---
.../bindings/arm/altera/socfpga-sdram-edac.txt | 15 +++++++++++++++
arch/arm/boot/dts/socfpga.dtsi | 6 ++++++
2 files changed, 21 insertions(+)
create mode 100644 Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt

diff --git a/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
new file mode 100644
index 0000000..d68e033
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
@@ -0,0 +1,15 @@
+Altera SOCFPGA SDRAM Error Detection & Correction [EDAC]
+
+Required properties:
+- compatible : should contain "altr,sdram-edac";
+- reg : should contain the ECC register range in sdram
+ controller (address and length).
+- interrupts : Should contain the SDRAM ECC IRQ in the
+ appropriate format for the IRQ controller.
+
+Example:
+ sdramedac@ffc2502c {
+ compatible = "altr,sdram-edac";
+ reg = <0xffc2502c 0x28>;
+ interrupts = <0 39 4>;
+ };
diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi
index 310292e..da0785d 100644
--- a/arch/arm/boot/dts/socfpga.dtsi
+++ b/arch/arm/boot/dts/socfpga.dtsi
@@ -687,6 +687,12 @@
reg = <0xffc25000 0x4>;
};

+ sdramedac@ffc2502c {
+ compatible = "altr,sdram-edac";
+ reg = <0xffc2502c 0x28>;
+ interrupts = <0 39 4>;
+ };
+
rst: rstmgr@ffd05000 {
compatible = "altr,rst-mgr";
reg = <0xffd05000 0x1000>;
--
1.7.9.5

2014-06-25 21:09:09

by Thor Thayer

[permalink] [raw]
Subject: [PATCHv7 1/3] devicetree: Addition of the Altera SDRAM Controller.

From: Thor Thayer <[email protected]>

Add the Altera SDRAM controller bindings and device tree changes to the Altera SoC project.

Signed-off-by: Thor Thayer <[email protected]>
---
v2: Changes to SoC SDRAM EDAC code.

v3: Implement code suggestions for SDRAM EDAC code.

v4: Remove syscon from SDRAM controller bindings.

v5: No Change, bump version for consistency.

v6: Only map the ctrlcfg register as syscon.

v7: No change. Bump for consistency.
---
.../bindings/arm/altera/socfpga-sdram.txt | 11 +++++++++++
arch/arm/boot/dts/socfpga.dtsi | 5 +++++
2 files changed, 16 insertions(+)
create mode 100644 Documentation/devicetree/bindings/arm/altera/socfpga-sdram.txt

diff --git a/Documentation/devicetree/bindings/arm/altera/socfpga-sdram.txt b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram.txt
new file mode 100644
index 0000000..5027026
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram.txt
@@ -0,0 +1,11 @@
+Altera SOCFPGA SDRAM Controller
+
+Required properties:
+- compatible : "altr,sdr-ctl";
+- reg : Should contain 1 register ranges(address and length)
+
+Example:
+ sdrctl@ffc25000 {
+ compatible = "altr,sdr-ctl";
+ reg = <0xffc25000 0x4>;
+ };
diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi
index 4676f25..310292e 100644
--- a/arch/arm/boot/dts/socfpga.dtsi
+++ b/arch/arm/boot/dts/socfpga.dtsi
@@ -682,6 +682,11 @@
clocks = <&l4_sp_clk>;
};

+ sdrctl@ffc25000 {
+ compatible = "altr,sdr-ctl", "syscon";
+ reg = <0xffc25000 0x4>;
+ };
+
rst: rstmgr@ffd05000 {
compatible = "altr,rst-mgr";
reg = <0xffd05000 0x1000>;
--
1.7.9.5

2014-06-25 21:09:37

by Thor Thayer

[permalink] [raw]
Subject: [PATCHv7 3/3] edac: altera: Add EDAC support for Altera SoC SDRAM Controller.

From: Thor Thayer <[email protected]>

This patch adds support for the CycloneV and ArriaV SDRAM controllers. Correction and reporting of SBEs, Panic on DBEs.

Signed-off-by: Thor Thayer <[email protected]>
---
v2: Use the SDRAM controller registers to calculate memory size
instead of the Device Tree. Update To & Cc list. Add maintainer
information.

v3: EDAC driver cleanup based on comments from Mailing list.

v4: Panic on DBE. Add macro around inject-error reads to prevent
them from being optimized out. Remove of_match_ptr since this
will always use Device Tree.

v5: Addition of printk to trigger function to ensure read vars
are not optimized out.

v6: Changes to split out shared SDRAM controller reg (offset 0x00)
as a syscon device and allocate ECC specific SDRAM registers
to EDAC.

v7: No change. Bump version for consistency.
---
drivers/edac/Kconfig | 9 +
drivers/edac/Makefile | 2 +
drivers/edac/altera_edac.c | 448 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 459 insertions(+)
create mode 100644 drivers/edac/altera_edac.c

diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
index 878f090..4f4d379 100644
--- a/drivers/edac/Kconfig
+++ b/drivers/edac/Kconfig
@@ -368,4 +368,13 @@ config EDAC_OCTEON_PCI
Support for error detection and correction on the
Cavium Octeon family of SOCs.

+config EDAC_ALTERA_MC
+ bool "Altera SDRAM Memory Controller EDAC"
+ depends on EDAC_MM_EDAC && ARCH_SOCFPGA
+ help
+ Support for error detection and correction on the
+ Altera SDRAM memory controller. Note that the
+ preloader must initialize the SDRAM before loading
+ the kernel.
+
endif # EDAC
diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
index 4154ed6..9741336 100644
--- a/drivers/edac/Makefile
+++ b/drivers/edac/Makefile
@@ -64,3 +64,5 @@ obj-$(CONFIG_EDAC_OCTEON_PC) += octeon_edac-pc.o
obj-$(CONFIG_EDAC_OCTEON_L2C) += octeon_edac-l2c.o
obj-$(CONFIG_EDAC_OCTEON_LMC) += octeon_edac-lmc.o
obj-$(CONFIG_EDAC_OCTEON_PCI) += octeon_edac-pci.o
+
+obj-$(CONFIG_EDAC_ALTERA_MC) += altera_edac.o
diff --git a/drivers/edac/altera_edac.c b/drivers/edac/altera_edac.c
new file mode 100644
index 0000000..e3fcd27
--- /dev/null
+++ b/drivers/edac/altera_edac.c
@@ -0,0 +1,448 @@
+/*
+ * Copyright Altera Corporation (C) 2014. All rights reserved.
+ * Copyright 2011-2012 Calxeda, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+
+ *
+ * Adapted from the highbank_mc_edac driver
+ *
+ */
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/ctype.h>
+#include <linux/edac.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/of_platform.h>
+#include <linux/uaccess.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+
+#include "edac_core.h"
+#include "edac_module.h"
+
+#define EDAC_MOD_STR "altera_edac"
+#define EDAC_VERSION "1"
+
+/* SDRAM Controller CtrlCfg Register */
+#define CTLCFG 0x00
+
+/* SDRAM Controller CtrlCfg Register Bit Masks */
+#define CTLCFG_ECC_EN 0x400
+#define CTLCFG_ECC_CORR_EN 0x800
+#define CTLCFG_GEN_SB_ERR 0x2000
+#define CTLCFG_GEN_DB_ERR 0x4000
+
+#define CTLCFG_ECC_AUTO_EN (CTLCFG_ECC_EN | \
+ CTLCFG_ECC_CORR_EN)
+
+/* SDRAM Controller ECC Register Offset */
+#define ECC_REG_OFFSET 0x2C
+
+/* SDRAM Controller Address Width Register */
+#define DRAMADDRW (0x2C-ECC_REG_OFFSET)
+
+/* SDRAM Controller Address Widths Field Register */
+#define DRAMADDRW_COLBIT_MASK 0x001F
+#define DRAMADDRW_COLBIT_LSB 0
+#define DRAMADDRW_ROWBIT_MASK 0x03E0
+#define DRAMADDRW_ROWBIT_LSB 5
+#define DRAMADDRW_BANKBIT_MASK 0x1C00
+#define DRAMADDRW_BANKBIT_LSB 10
+#define DRAMADDRW_CSBIT_MASK 0xE000
+#define DRAMADDRW_CSBIT_LSB 13
+
+/* SDRAM Controller Interface Data Width Register */
+#define DRAMIFWIDTH (0x30-ECC_REG_OFFSET)
+
+/* SDRAM Controller Interface Data Width Defines */
+#define DRAMIFWIDTH_16B_ECC 24
+#define DRAMIFWIDTH_32B_ECC 40
+
+/* SDRAM Controller DRAM Status Register */
+#define DRAMSTS (0x38-ECC_REG_OFFSET)
+
+/* SDRAM Controller DRAM Status Register Bit Masks */
+#define DRAMSTS_SBEERR 0x04
+#define DRAMSTS_DBEERR 0x08
+#define DRAMSTS_CORR_DROP 0x10
+
+/* SDRAM Controller DRAM IRQ Register */
+#define DRAMINTR (0x3C-ECC_REG_OFFSET)
+
+/* SDRAM Controller DRAM IRQ Register Bit Masks */
+#define DRAMINTR_INTREN 0x01
+#define DRAMINTR_SBEMASK 0x02
+#define DRAMINTR_DBEMASK 0x04
+#define DRAMINTR_CORRDROPMASK 0x08
+#define DRAMINTR_INTRCLR 0x10
+
+/* SDRAM Controller Single Bit Error Count Register */
+#define SBECOUNT (0x40-ECC_REG_OFFSET)
+
+/* SDRAM Controller Single Bit Error Count Register Bit Masks */
+#define SBECOUNT_MASK 0x0F
+
+/* SDRAM Controller Double Bit Error Count Register */
+#define DBECOUNT (0x44-ECC_REG_OFFSET)
+
+/* SDRAM Controller Double Bit Error Count Register Bit Masks */
+#define DBECOUNT_MASK 0x0F
+
+/* SDRAM Controller ECC Error Address Register */
+#define ERRADDR (0x48-ECC_REG_OFFSET)
+
+/* SDRAM Controller ECC Error Address Register Bit Masks */
+#define ERRADDR_MASK 0xFFFFFFFF
+
+/* SDRAM Controller ECC Autocorrect Drop Count Register */
+#define DROPCOUNT (0x4C-ECC_REG_OFFSET)
+
+/* SDRAM Controller ECC Autocorrect Drop Count Register Bit Masks */
+#define DROPCOUNT_MASK 0x0F
+
+/* SDRAM Controller ECC AutoCorrect Address Register */
+#define DROPADDR (0x50-ECC_REG_OFFSET)
+
+/* SDRAM Controller ECC AutoCorrect Error Address Register Bit Masks */
+#define DROPADDR_MASK 0xFFFFFFFF
+
+/* Altera SDRAM Memory Controller data */
+struct altr_sdram_mc_data {
+ struct regmap *mc_vconfig;
+ void __iomem *mc_vecc_regs;
+};
+
+static irqreturn_t altr_sdram_mc_err_handler(int irq, void *dev_id)
+{
+ struct mem_ctl_info *mci = dev_id;
+ struct altr_sdram_mc_data *drvdata = mci->pvt_info;
+ u32 status, err_count, err_addr;
+
+ /* Error Address is shared by both SBE & DBE */
+ err_addr = readl(drvdata->mc_vecc_regs + ERRADDR);
+
+ status = readl(drvdata->mc_vecc_regs + DRAMSTS);
+
+ if (status & DRAMSTS_DBEERR) {
+ err_count = readl(drvdata->mc_vecc_regs + DBECOUNT);
+ panic("\nEDAC: [%d Uncorrectable errors @ 0x%08X]\n",
+ err_count, err_addr);
+ }
+ if (status & DRAMSTS_SBEERR) {
+ err_count = readl(drvdata->mc_vecc_regs + SBECOUNT);
+ edac_mc_handle_error(HW_EVENT_ERR_CORRECTED, mci, err_count,
+ err_addr >> PAGE_SHIFT,
+ err_addr & ~PAGE_MASK, 0,
+ 0, 0, -1, mci->ctl_name, "");
+ }
+
+ writel((DRAMINTR_INTRCLR | DRAMINTR_INTREN),
+ drvdata->mc_vecc_regs + DRAMINTR);
+
+ return IRQ_HANDLED;
+}
+
+#ifdef CONFIG_EDAC_DEBUG
+static ssize_t altr_sdr_mc_err_inject_write(struct file *file,
+ const char __user *data,
+ size_t count, loff_t *ppos)
+{
+ struct mem_ctl_info *mci = file->private_data;
+ struct altr_sdram_mc_data *drvdata = mci->pvt_info;
+ u32 *ptemp;
+ dma_addr_t dma_handle;
+ u32 reg, read_reg;
+
+ ptemp = dma_alloc_coherent(mci->pdev, 16, &dma_handle, GFP_KERNEL);
+ if (IS_ERR(ptemp)) {
+ dma_free_coherent(mci->pdev, 16, ptemp, dma_handle);
+ edac_printk(KERN_ERR, EDAC_MC,
+ "Inject: Buffer Allocation error\n");
+ return -ENOMEM;
+ }
+
+ regmap_read(drvdata->mc_vconfig, CTLCFG, &read_reg);
+ read_reg &= ~(CTLCFG_GEN_SB_ERR | CTLCFG_GEN_DB_ERR);
+
+ if (count == 3) {
+ dev_alert(mci->pdev, "EDAC Inject Double bit error\n");
+ regmap_write(drvdata->mc_vconfig, CTLCFG,
+ (read_reg | CTLCFG_GEN_DB_ERR));
+ } else {
+ dev_alert(mci->pdev, "EDAC Inject Single bit error\n");
+ regmap_write(drvdata->mc_vconfig, CTLCFG,
+ (read_reg | CTLCFG_GEN_SB_ERR));
+ }
+
+ ptemp[0] = 0x5A5A5A5A;
+ ptemp[1] = 0xA5A5A5A5;
+ /* Clear the error injection bits */
+ regmap_write(drvdata->mc_vconfig, CTLCFG, read_reg);
+ /* Ensure it has been written out */
+ wmb();
+
+ /*
+ * To trigger the error, we need to read the data back
+ * (the data was written with errors above)
+ * The ACCESS_ONCE macros are used to prevent the
+ * compiler optimizing these reads out.
+ */
+ reg = ACCESS_ONCE(ptemp[0]);
+ read_reg = ACCESS_ONCE(ptemp[1]);
+ /* Force Read */
+ rmb();
+
+ edac_printk(KERN_ALERT, EDAC_MC, "Read Data [0x%X, 0x%X]\n",
+ reg, read_reg);
+
+ dma_free_coherent(mci->pdev, 16, ptemp, dma_handle);
+
+ return count;
+}
+
+static const struct file_operations altr_sdr_mc_debug_inject_fops = {
+ .open = simple_open,
+ .write = altr_sdr_mc_err_inject_write,
+ .llseek = generic_file_llseek,
+};
+
+static void altr_sdr_mc_create_debugfs_nodes(struct mem_ctl_info *mci)
+{
+ if (mci->debugfs)
+ debugfs_create_file("inject_ctrl", S_IWUSR, mci->debugfs, mci,
+ &altr_sdr_mc_debug_inject_fops);
+}
+#else
+static void altr_sdr_mc_create_debugfs_nodes(struct mem_ctl_info *mci)
+{}
+#endif
+
+/* Get total memory size in bytes */
+static u32 altr_sdram_get_total_mem_size(void __iomem *mc_vbase)
+{
+ u32 size;
+ u32 read_reg, row, bank, col, cs, width;
+
+ read_reg = readl(mc_vbase + DRAMADDRW);
+
+ width = readl(mc_vbase + DRAMIFWIDTH);
+
+ col = (read_reg & DRAMADDRW_COLBIT_MASK) >>
+ DRAMADDRW_COLBIT_LSB;
+ row = (read_reg & DRAMADDRW_ROWBIT_MASK) >>
+ DRAMADDRW_ROWBIT_LSB;
+ bank = (read_reg & DRAMADDRW_BANKBIT_MASK) >>
+ DRAMADDRW_BANKBIT_LSB;
+ cs = (read_reg & DRAMADDRW_CSBIT_MASK) >>
+ DRAMADDRW_CSBIT_LSB;
+
+ /* Correct for ECC as its not addressible */
+ if (width == DRAMIFWIDTH_32B_ECC)
+ width = 32;
+ if (width == DRAMIFWIDTH_16B_ECC)
+ width = 16;
+
+ /* calculate the SDRAM size base on this info */
+ size = 1 << (row + bank + col);
+ size = size * cs * (width / 8);
+
+ return size;
+}
+
+static int altr_sdram_probe(struct platform_device *pdev)
+{
+ struct edac_mc_layer layers[2];
+ struct mem_ctl_info *mci;
+ struct altr_sdram_mc_data *drvdata;
+ struct regmap *mc_vconfig;
+ void __iomem *mc_vregs;
+ struct dimm_info *dimm;
+ u32 read_reg, mem_size;
+ struct resource *r;
+ int irq;
+ int res = 0;
+
+ /* Validate the SDRAM controller has ECC enabled */
+ /* Grab the register values from the sdr-ctl in device tree */
+ mc_vconfig = syscon_regmap_lookup_by_compatible("altr,sdr-ctl");
+ if (IS_ERR(mc_vconfig)) {
+ edac_printk(KERN_ERR, EDAC_MC,
+ "regmap for altr,sdr-ctl lookup failed.\n");
+ return -ENODEV;
+ }
+
+ if (regmap_read(mc_vconfig, CTLCFG, &read_reg) ||
+ ((read_reg & CTLCFG_ECC_AUTO_EN) != CTLCFG_ECC_AUTO_EN)) {
+ edac_printk(KERN_ERR, EDAC_MC,
+ "No ECC/ECC disabled [0x%08X]\n", read_reg);
+ return -ENODEV;
+ }
+
+ /* Allocate the ECC Registers */
+ r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!r) {
+ edac_printk(KERN_ERR, EDAC_MC, "Unable to get mem resource\n");
+ return -ENODEV;
+ }
+
+ if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL)) {
+ res = -ENOMEM;
+ goto err;
+ }
+
+ mc_vregs = devm_ioremap_resource(&pdev->dev, r);
+ if (IS_ERR(mc_vregs)) {
+ edac_printk(KERN_ERR, EDAC_MC,
+ "Error while requesting mem region\n");
+ res = PTR_ERR(mc_vregs);
+ goto err;
+ }
+
+ edac_printk(KERN_ERR, EDAC_MC,
+ "Allocated [%p] with [start:0x%X size:%d]\n", mc_vregs,
+ r->start, resource_size(r));
+
+ /* Grab memory size from SDRAM Controller registers. */
+ mem_size = altr_sdram_get_total_mem_size(mc_vregs);
+ if (mem_size <= 0) {
+ edac_printk(KERN_ERR, EDAC_MC,
+ "Unable to calculate memory size\n");
+ res = -ENODEV;
+ goto err;
+ }
+
+ edac_printk(KERN_ERR, EDAC_MC,
+ "SDRAM Memory size %d [0x%X]\n", mem_size, mem_size);
+
+ /* Ensure the SDRAM Interrupt is disabled and cleared */
+ writel(DRAMINTR_INTRCLR, mc_vregs + DRAMINTR);
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ edac_printk(KERN_ERR, EDAC_MC,
+ "No irq %d in DT\n", irq);
+ res = -ENODEV;
+ goto err;
+ }
+
+ layers[0].type = EDAC_MC_LAYER_CHIP_SELECT;
+ layers[0].size = 1;
+ layers[0].is_virt_csrow = true;
+ layers[1].type = EDAC_MC_LAYER_CHANNEL;
+ layers[1].size = 1;
+ layers[1].is_virt_csrow = false;
+ mci = edac_mc_alloc(0, ARRAY_SIZE(layers), layers,
+ sizeof(struct altr_sdram_mc_data));
+ if (!mci) {
+ edac_printk(KERN_ERR, EDAC_MC,
+ "Unable to allocate edac mci\n");
+ res = -ENOMEM;
+ goto err;
+ }
+
+ mci->pdev = &pdev->dev;
+ drvdata = mci->pvt_info;
+ drvdata->mc_vconfig = mc_vconfig;
+ drvdata->mc_vecc_regs = mc_vregs;
+ platform_set_drvdata(pdev, mci);
+
+ mci->mtype_cap = MEM_FLAG_DDR3;
+ mci->edac_ctl_cap = EDAC_FLAG_NONE | EDAC_FLAG_SECDED;
+ mci->edac_cap = EDAC_FLAG_SECDED;
+ mci->mod_name = EDAC_MOD_STR;
+ mci->mod_ver = EDAC_VERSION;
+ mci->ctl_name = dev_name(&pdev->dev);
+ mci->scrub_mode = SCRUB_SW_SRC;
+ mci->dev_name = dev_name(&pdev->dev);
+
+ dimm = *mci->dimms;
+ dimm->nr_pages = ((mem_size - 1) >> PAGE_SHIFT) + 1;
+ dimm->grain = 8;
+ dimm->dtype = DEV_X8;
+ dimm->mtype = MEM_DDR3;
+ dimm->edac_mode = EDAC_SECDED;
+
+ res = edac_mc_add_mc(mci);
+ if (res < 0)
+ goto free;
+
+ res = devm_request_irq(&pdev->dev, irq, altr_sdram_mc_err_handler,
+ 0, dev_name(&pdev->dev), mci);
+ if (res < 0) {
+ edac_mc_printk(mci, KERN_ERR,
+ "Unable to request irq %d\n", irq);
+ res = -ENODEV;
+ goto err2;
+ }
+
+ writel((DRAMINTR_INTRCLR | DRAMINTR_INTREN), mc_vregs + DRAMINTR);
+ if ((readl(mc_vregs + DRAMINTR) & (DRAMINTR_INTRCLR | DRAMINTR_INTREN))
+ != DRAMINTR_INTREN) {
+ edac_mc_printk(mci, KERN_ERR,
+ "Error enabling SDRAM ECC IRQ\n");
+ res = -ENODEV;
+ goto err2;
+ }
+
+ altr_sdr_mc_create_debugfs_nodes(mci);
+
+ devres_close_group(&pdev->dev, NULL);
+
+ return 0;
+
+err2:
+ edac_mc_del_mc(&pdev->dev);
+free:
+ edac_mc_free(mci);
+err:
+ devres_release_group(&pdev->dev, NULL);
+ edac_printk(KERN_ERR, EDAC_MC,
+ "EDAC Probe Failed; Error %d\n", res);
+
+ return res;
+}
+
+static int altr_sdram_remove(struct platform_device *pdev)
+{
+ struct mem_ctl_info *mci = platform_get_drvdata(pdev);
+
+ edac_mc_del_mc(&pdev->dev);
+ edac_mc_free(mci);
+ platform_set_drvdata(pdev, NULL);
+
+ return 0;
+}
+
+static const struct of_device_id altr_sdram_ctrl_of_match[] = {
+ { .compatible = "altr,sdram-edac", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, altr_sdram_ctrl_of_match);
+
+static struct platform_driver altr_sdram_edac_driver = {
+ .probe = altr_sdram_probe,
+ .remove = altr_sdram_remove,
+ .driver = {
+ .name = "altr_sdram_edac",
+ .of_match_table = altr_sdram_ctrl_of_match,
+ },
+};
+
+module_platform_driver(altr_sdram_edac_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Altera Corporation");
+MODULE_DESCRIPTION("EDAC Driver for Altera SDRAM Controller");
--
1.7.9.5

2014-06-25 21:12:58

by Dinh Nguyen

[permalink] [raw]
Subject: Re: [PATCHv7 3/3] edac: altera: Add EDAC support for Altera SoC SDRAM Controller.

Hi Thor,

On 06/25/2014 04:15 PM, [email protected] wrote:
> From: Thor Thayer <[email protected]>
>
> This patch adds support for the CycloneV and ArriaV SDRAM controllers. Correction and reporting of SBEs, Panic on DBEs.
>
> Signed-off-by: Thor Thayer <[email protected]>
> ---
> v2: Use the SDRAM controller registers to calculate memory size
> instead of the Device Tree. Update To & Cc list. Add maintainer
> information.
>
> v3: EDAC driver cleanup based on comments from Mailing list.
>
> v4: Panic on DBE. Add macro around inject-error reads to prevent
> them from being optimized out. Remove of_match_ptr since this
> will always use Device Tree.
>
> v5: Addition of printk to trigger function to ensure read vars
> are not optimized out.
>
> v6: Changes to split out shared SDRAM controller reg (offset 0x00)
> as a syscon device and allocate ECC specific SDRAM registers
> to EDAC.
>
> v7: No change. Bump version for consistency.
> ---
> drivers/edac/Kconfig | 9 +
> drivers/edac/Makefile | 2 +
> drivers/edac/altera_edac.c | 448 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 459 insertions(+)
> create mode 100644 drivers/edac/altera_edac.c
>
> diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
> index 878f090..4f4d379 100644
> --- a/drivers/edac/Kconfig
> +++ b/drivers/edac/Kconfig
> @@ -368,4 +368,13 @@ config EDAC_OCTEON_PCI
> Support for error detection and correction on the
> Cavium Octeon family of SOCs.
>
> +config EDAC_ALTERA_MC
> + bool "Altera SDRAM Memory Controller EDAC"
> + depends on EDAC_MM_EDAC && ARCH_SOCFPGA
> + help
> + Support for error detection and correction on the
> + Altera SDRAM memory controller. Note that the
> + preloader must initialize the SDRAM before loading
> + the kernel.
> +
> endif # EDAC
> diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
> index 4154ed6..9741336 100644
> --- a/drivers/edac/Makefile
> +++ b/drivers/edac/Makefile
> @@ -64,3 +64,5 @@ obj-$(CONFIG_EDAC_OCTEON_PC) += octeon_edac-pc.o
> obj-$(CONFIG_EDAC_OCTEON_L2C) += octeon_edac-l2c.o
> obj-$(CONFIG_EDAC_OCTEON_LMC) += octeon_edac-lmc.o
> obj-$(CONFIG_EDAC_OCTEON_PCI) += octeon_edac-pci.o
> +
> +obj-$(CONFIG_EDAC_ALTERA_MC) += altera_edac.o
> diff --git a/drivers/edac/altera_edac.c b/drivers/edac/altera_edac.c
> new file mode 100644
> index 0000000..e3fcd27
> --- /dev/null
> +++ b/drivers/edac/altera_edac.c
> @@ -0,0 +1,448 @@
> +/*
> + * Copyright Altera Corporation (C) 2014. All rights reserved.
> + * Copyright 2011-2012 Calxeda, Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
> + * more details.
> + *
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License. See the file "COPYING" in the main directory of this archive
> + * for more details.
> +
> + *
> + * Adapted from the highbank_mc_edac driver
> + *
> + */
> +#include <linux/types.h>
> +#include <linux/kernel.h>
> +#include <linux/ctype.h>
> +#include <linux/edac.h>
> +#include <linux/interrupt.h>
> +#include <linux/platform_device.h>
> +#include <linux/of_platform.h>
> +#include <linux/uaccess.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
>

Did you miss my comment to put these headers in alpabetical order?

Dinh

2014-06-25 21:22:17

by Thor Thayer

[permalink] [raw]
Subject: Re: [PATCHv7 3/3] edac: altera: Add EDAC support for Altera SoC SDRAM Controller.

Hi Dinh,

On Wed, Jun 25, 2014 at 4:12 PM, Dinh Nguyen <[email protected]> wrote:
> Hi Thor,
>
>
> On 06/25/2014 04:15 PM, [email protected] wrote:
>>
>> From: Thor Thayer <[email protected]>
>>
>> This patch adds support for the CycloneV and ArriaV SDRAM controllers.
>> Correction and reporting of SBEs, Panic on DBEs.
>>
>> Signed-off-by: Thor Thayer <[email protected]>
>> ---
>> v2: Use the SDRAM controller registers to calculate memory size
>> instead of the Device Tree. Update To & Cc list. Add maintainer
>> information.
>>
>> v3: EDAC driver cleanup based on comments from Mailing list.
>>
>> v4: Panic on DBE. Add macro around inject-error reads to prevent
>> them from being optimized out. Remove of_match_ptr since this
>> will always use Device Tree.
>>
>> v5: Addition of printk to trigger function to ensure read vars
>> are not optimized out.
>>
>> v6: Changes to split out shared SDRAM controller reg (offset 0x00)
>> as a syscon device and allocate ECC specific SDRAM registers
>> to EDAC.
>>
>> v7: No change. Bump version for consistency.
>> ---
>> drivers/edac/Kconfig | 9 +
>> drivers/edac/Makefile | 2 +
>> drivers/edac/altera_edac.c | 448
>> ++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 459 insertions(+)
>> create mode 100644 drivers/edac/altera_edac.c
>>
>> diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
>> index 878f090..4f4d379 100644
>> --- a/drivers/edac/Kconfig
>> +++ b/drivers/edac/Kconfig
>> @@ -368,4 +368,13 @@ config EDAC_OCTEON_PCI
>> Support for error detection and correction on the
>> Cavium Octeon family of SOCs.
>>
>> +config EDAC_ALTERA_MC
>> + bool "Altera SDRAM Memory Controller EDAC"
>> + depends on EDAC_MM_EDAC && ARCH_SOCFPGA
>> + help
>> + Support for error detection and correction on the
>> + Altera SDRAM memory controller. Note that the
>> + preloader must initialize the SDRAM before loading
>> + the kernel.
>> +
>> endif # EDAC
>> diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
>> index 4154ed6..9741336 100644
>> --- a/drivers/edac/Makefile
>> +++ b/drivers/edac/Makefile
>> @@ -64,3 +64,5 @@ obj-$(CONFIG_EDAC_OCTEON_PC) +=
>> octeon_edac-pc.o
>> obj-$(CONFIG_EDAC_OCTEON_L2C) += octeon_edac-l2c.o
>> obj-$(CONFIG_EDAC_OCTEON_LMC) += octeon_edac-lmc.o
>> obj-$(CONFIG_EDAC_OCTEON_PCI) += octeon_edac-pci.o
>> +
>> +obj-$(CONFIG_EDAC_ALTERA_MC) += altera_edac.o
>> diff --git a/drivers/edac/altera_edac.c b/drivers/edac/altera_edac.c
>> new file mode 100644
>> index 0000000..e3fcd27
>> --- /dev/null
>> +++ b/drivers/edac/altera_edac.c
>> @@ -0,0 +1,448 @@
>> +/*
>> + * Copyright Altera Corporation (C) 2014. All rights reserved.
>> + * Copyright 2011-2012 Calxeda, Inc.
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms and conditions of the GNU General Public License,
>> + * version 2, as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope it will be useful, but WITHOUT
>> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
>> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
>> for
>> + * more details.
>> + *
>> + * This file is subject to the terms and conditions of the GNU General
>> Public
>> + * License. See the file "COPYING" in the main directory of this archive
>> + * for more details.
>> +
>> + *
>> + * Adapted from the highbank_mc_edac driver
>> + *
>> + */
>> +#include <linux/types.h>
>> +#include <linux/kernel.h>
>> +#include <linux/ctype.h>
>> +#include <linux/edac.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/of_platform.h>
>> +#include <linux/uaccess.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/regmap.h>
>>
>
> Did you miss my comment to put these headers in alpabetical order?
>
> Dinh

Yep, I missed your comment - looking at it now.

2014-06-26 09:45:32

by Mark Rutland

[permalink] [raw]
Subject: Re: [PATCHv7 2/3] devicetree: Addition of the Altera SDRAM EDAC.

On Wed, Jun 25, 2014 at 10:15:26PM +0100, [email protected] wrote:
> From: Thor Thayer <[email protected]>
>
> Add the Altera SDRAM EDAC bindings and device tree changes to the Altera SoC project.
>
> Signed-off-by: Thor Thayer <[email protected]>
> ---
> v2: Changes to SoC EDAC source code.
>
> v3: Fix typo in device tree documentation.
>
> v4,v5: No changes - bump version for consistency.
>
> v6: Assign ECC registers in SDRAM controller to EDAC
>
> v7: Fix SDRAM EDAC base address.
> ---
> .../bindings/arm/altera/socfpga-sdram-edac.txt | 15 +++++++++++++++
> arch/arm/boot/dts/socfpga.dtsi | 6 ++++++
> 2 files changed, 21 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
>
> diff --git a/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
> new file mode 100644
> index 0000000..d68e033
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
> @@ -0,0 +1,15 @@
> +Altera SOCFPGA SDRAM Error Detection & Correction [EDAC]
> +
> +Required properties:
> +- compatible : should contain "altr,sdram-edac";
> +- reg : should contain the ECC register range in sdram
> + controller (address and length).
> +- interrupts : Should contain the SDRAM ECC IRQ in the
> + appropriate format for the IRQ controller.
> +
> +Example:
> + sdramedac@ffc2502c {
> + compatible = "altr,sdram-edac";
> + reg = <0xffc2502c 0x28>;
> + interrupts = <0 39 4>;
> + };
> diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi
> index 310292e..da0785d 100644
> --- a/arch/arm/boot/dts/socfpga.dtsi
> +++ b/arch/arm/boot/dts/socfpga.dtsi
> @@ -687,6 +687,12 @@
> reg = <0xffc25000 0x4>;
> };
>
> + sdramedac@ffc2502c {
> + compatible = "altr,sdram-edac";
> + reg = <0xffc2502c 0x28>;
> + interrupts = <0 39 4>;
> + };

I'm not sure I understand this. The ECC register existing within the
SDRAM controller, which we have a binding for. Why do we need a separate
binding for a subset of registers within an IP block?

Why can we not have a single binding for the entire SDRAM controlelr and
decompse that within Linux as it makes sense for the appropriate
subsystyems?

Leaking Linux design into bindings is a bad idea; it makes it harder to
change things.

Mark.

2014-06-27 15:37:25

by Thor Thayer

[permalink] [raw]
Subject: Re: [PATCHv7 2/3] devicetree: Addition of the Altera SDRAM EDAC.

Hi Mark

On Thu, Jun 26, 2014 at 4:45 AM, Mark Rutland <[email protected]> wrote:
> On Wed, Jun 25, 2014 at 10:15:26PM +0100, [email protected] wrote:
>> From: Thor Thayer <[email protected]>
>>
>> Add the Altera SDRAM EDAC bindings and device tree changes to the Altera SoC project.
>>
>> Signed-off-by: Thor Thayer <[email protected]>
>> ---
>> v2: Changes to SoC EDAC source code.
>>
>> v3: Fix typo in device tree documentation.
>>
>> v4,v5: No changes - bump version for consistency.
>>
>> v6: Assign ECC registers in SDRAM controller to EDAC
>>
>> v7: Fix SDRAM EDAC base address.
>> ---
>> .../bindings/arm/altera/socfpga-sdram-edac.txt | 15 +++++++++++++++
>> arch/arm/boot/dts/socfpga.dtsi | 6 ++++++
>> 2 files changed, 21 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
>>
>> diff --git a/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
>> new file mode 100644
>> index 0000000..d68e033
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
>> @@ -0,0 +1,15 @@
>> +Altera SOCFPGA SDRAM Error Detection & Correction [EDAC]
>> +
>> +Required properties:
>> +- compatible : should contain "altr,sdram-edac";
>> +- reg : should contain the ECC register range in sdram
>> + controller (address and length).
>> +- interrupts : Should contain the SDRAM ECC IRQ in the
>> + appropriate format for the IRQ controller.
>> +
>> +Example:
>> + sdramedac@ffc2502c {
>> + compatible = "altr,sdram-edac";
>> + reg = <0xffc2502c 0x28>;
>> + interrupts = <0 39 4>;
>> + };
>> diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi
>> index 310292e..da0785d 100644
>> --- a/arch/arm/boot/dts/socfpga.dtsi
>> +++ b/arch/arm/boot/dts/socfpga.dtsi
>> @@ -687,6 +687,12 @@
>> reg = <0xffc25000 0x4>;
>> };
>>
>> + sdramedac@ffc2502c {
>> + compatible = "altr,sdram-edac";
>> + reg = <0xffc2502c 0x28>;
>> + interrupts = <0 39 4>;
>> + };
>
> I'm not sure I understand this. The ECC register existing within the
> SDRAM controller, which we have a binding for. Why do we need a separate
> binding for a subset of registers within an IP block?
>
> Why can we not have a single binding for the entire SDRAM controlelr and
> decompse that within Linux as it makes sense for the appropriate
> subsystyems?
>
> Leaking Linux design into bindings is a bad idea; it makes it harder to
> change things.
>
> Mark.

Sorry, I missed your reply. Luckily Dinh pointed it out to me.

The SDRAM Controller binding is just 1 register but it includes
bitfields that describe the SDRAM configuration as well as some
bitfields for ECC. Ideally the ECC bitfields would be in a separate
register and could be included in the SDRAM EDAC block.

It is anticipated that other drivers and U-Boot may need to read the
SDRAM configuration which is why this register contains a "syscon"
designation.

The SDRAM EDAC block is a set of registers in the SDRAM Controller IP
register space that are ECC specific. I was thinking this should be a
separate binding since it encompasses 1 complete task but I see your
point about just having 1 binding.

I appreciate your help on figuring the proper way to handle this.
Sorry about reposting without addressing your comment.

Thanks,

Thor

2014-07-08 11:31:14

by Pavel Machek

[permalink] [raw]
Subject: Re: [PATCHv7 3/3] edac: altera: Add EDAC support for Altera SoC SDRAM Controller.

> + read_reg = readl(mc_vbase + DRAMADDRW);
> +
> + width = readl(mc_vbase + DRAMIFWIDTH);
> +
> + col = (read_reg & DRAMADDRW_COLBIT_MASK) >>
> + DRAMADDRW_COLBIT_LSB;
> + row = (read_reg & DRAMADDRW_ROWBIT_MASK) >>
> + DRAMADDRW_ROWBIT_LSB;
> + bank = (read_reg & DRAMADDRW_BANKBIT_MASK) >>
> + DRAMADDRW_BANKBIT_LSB;
> + cs = (read_reg & DRAMADDRW_CSBIT_MASK) >>
> + DRAMADDRW_CSBIT_LSB;

As I said, all the defines only make this harder to read. The code is
pretty obvious if you put numbers in here...

Plus I'd like an explanation/comment of how the error injection works.

Thanks,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

2014-07-08 11:42:35

by Borislav Petkov

[permalink] [raw]
Subject: Re: [PATCHv7 3/3] edac: altera: Add EDAC support for Altera SoC SDRAM Controller.

On Tue, Jul 08, 2014 at 01:31:09PM +0200, Pavel Machek wrote:
> > + read_reg = readl(mc_vbase + DRAMADDRW);
> > +
> > + width = readl(mc_vbase + DRAMIFWIDTH);
> > +
> > + col = (read_reg & DRAMADDRW_COLBIT_MASK) >>
> > + DRAMADDRW_COLBIT_LSB;
> > + row = (read_reg & DRAMADDRW_ROWBIT_MASK) >>
> > + DRAMADDRW_ROWBIT_LSB;
> > + bank = (read_reg & DRAMADDRW_BANKBIT_MASK) >>
> > + DRAMADDRW_BANKBIT_LSB;
> > + cs = (read_reg & DRAMADDRW_CSBIT_MASK) >>
> > + DRAMADDRW_CSBIT_LSB;
>
> As I said, all the defines only make this harder to read. The code is
> pretty obvious if you put numbers in here...

Since when it is a good coding practice to put naked numbers instead of
descriptive macro names??!

Now, I can understand that the macro names could be made more
descriptive so that you can understand what they mean, but naked
numbers?! You must be joking although 1st of April is long gone.

--
Regards/Gruss,
Boris.

Sent from a fat crate under my desk. Formatting is fine.
--

2014-07-08 11:52:09

by Pavel Machek

[permalink] [raw]
Subject: Re: [PATCHv7 3/3] edac: altera: Add EDAC support for Altera SoC SDRAM Controller.

On Tue 2014-07-08 13:42:28, Borislav Petkov wrote:
> On Tue, Jul 08, 2014 at 01:31:09PM +0200, Pavel Machek wrote:
> > > + read_reg = readl(mc_vbase + DRAMADDRW);
> > > +
> > > + width = readl(mc_vbase + DRAMIFWIDTH);
> > > +
> > > + col = (read_reg & DRAMADDRW_COLBIT_MASK) >>
> > > + DRAMADDRW_COLBIT_LSB;
> > > + row = (read_reg & DRAMADDRW_ROWBIT_MASK) >>
> > > + DRAMADDRW_ROWBIT_LSB;
> > > + bank = (read_reg & DRAMADDRW_BANKBIT_MASK) >>
> > > + DRAMADDRW_BANKBIT_LSB;
> > > + cs = (read_reg & DRAMADDRW_CSBIT_MASK) >>
> > > + DRAMADDRW_CSBIT_LSB;
> >
> > As I said, all the defines only make this harder to read. The code is
> > pretty obvious if you put numbers in here...
>
> Since when it is a good coding practice to put naked numbers instead of
> descriptive macro names??!
>
> Now, I can understand that the macro names could be made more
> descriptive so that you can understand what they mean, but naked
> numbers?! You must be joking although 1st of April is long gone.

I'm not joking. Try to understand and verify the code above. You
can't. The "descriptive macro names" are useless; all the code does is
split register in pieces. With the numbers it would be very obvious.


Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

2014-07-08 11:55:07

by Borislav Petkov

[permalink] [raw]
Subject: Re: [PATCHv7 3/3] edac: altera: Add EDAC support for Altera SoC SDRAM Controller.

On Tue, Jul 08, 2014 at 01:52:05PM +0200, Pavel Machek wrote:
> I'm not joking. Try to understand and verify the code above. You
> can't. The "descriptive macro names" are useless; all the code does is
> split register in pieces. With the numbers it would be very obvious.

No, you need to fix the names not switch to naked numbers.

--
Regards/Gruss,
Boris.

Sent from a fat crate under my desk. Formatting is fine.
--

2014-07-08 12:04:36

by Pavel Machek

[permalink] [raw]
Subject: Re: [PATCHv7 3/3] edac: altera: Add EDAC support for Altera SoC SDRAM Controller.

On Tue 2014-07-08 13:54:58, Borislav Petkov wrote:
> On Tue, Jul 08, 2014 at 01:52:05PM +0200, Pavel Machek wrote:
> > I'm not joking. Try to understand and verify the code above. You
> > can't. The "descriptive macro names" are useless; all the code does is
> > split register in pieces. With the numbers it would be very obvious.
>
> No, you need to fix the names not switch to naked numbers.

Hiding numbers that are used just once into defines to put them out of
sight does not really help readability.

Compare:

+#define DRAMADDRW_COLBIT_MASK 0x001F
+#define DRAMADDRW_COLBIT_LSB 0
+#define DRAMADDRW_ROWBIT_MASK 0x02E0
+#define DRAMADDRW_ROWBIT_LSB 5
+#define DRAMADDRW_BANKBIT_MASK 0x1C00
+#define DRAMADDRW_BANKBIT_LSB 10
+#define DRAMADDRW_CSBIT_MASK 0xE000
+#define DRAMADDRW_CSBIT_LSB 13

(Insert few screens of code so that you have to scroll or split
window).

What information do the define names have? None, I already know how
hardware registers work.

+ col = (read_reg & DRAMADDRW_COLBIT_MASK) >>
+ DRAMADDRW_COLBIT_LSB;
+ row = (read_reg & DRAMADDRW_ROWBIT_MASK) >>
+ DRAMADDRW_ROWBIT_LSB;
+ bank = (read_reg & DRAMADDRW_BANKBIT_MASK) >>
+ DRAMADDRW_BANKBIT_LSB;
+ cs = (read_reg & DRAMADDRW_CSBIT_MASK) >>
+ DRAMADDRW_CSBIT_LSB;

Instead, we could have:

col = read_reg & 0x001F;
row = (read_reg & 0x02E0) >> 5;
bank = (read_reg & 0x1C00) >> 10;
cs = (read_reg & 0xE000) >> 13;

All information is preserved, code is shorter and easier to understand.

Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

2014-07-09 20:07:51

by Thor Thayer

[permalink] [raw]
Subject: Re: [PATCHv7 2/3] devicetree: Addition of the Altera SDRAM EDAC.

On Thu, Jun 26, 2014 at 4:45 AM, Mark Rutland <[email protected]> wrote:
> On Wed, Jun 25, 2014 at 10:15:26PM +0100, [email protected] wrote:
>> From: Thor Thayer <[email protected]>
>>
>> Add the Altera SDRAM EDAC bindings and device tree changes to the Altera SoC project.
>>
>> Signed-off-by: Thor Thayer <[email protected]>
>> ---
>> v2: Changes to SoC EDAC source code.
>>
>> v3: Fix typo in device tree documentation.
>>
>> v4,v5: No changes - bump version for consistency.
>>
>> v6: Assign ECC registers in SDRAM controller to EDAC
>>
>> v7: Fix SDRAM EDAC base address.
>> ---
>> .../bindings/arm/altera/socfpga-sdram-edac.txt | 15 +++++++++++++++
>> arch/arm/boot/dts/socfpga.dtsi | 6 ++++++
>> 2 files changed, 21 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
>>
>> diff --git a/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
>> new file mode 100644
>> index 0000000..d68e033
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
>> @@ -0,0 +1,15 @@
>> +Altera SOCFPGA SDRAM Error Detection & Correction [EDAC]
>> +
>> +Required properties:
>> +- compatible : should contain "altr,sdram-edac";
>> +- reg : should contain the ECC register range in sdram
>> + controller (address and length).
>> +- interrupts : Should contain the SDRAM ECC IRQ in the
>> + appropriate format for the IRQ controller.
>> +
>> +Example:
>> + sdramedac@ffc2502c {
>> + compatible = "altr,sdram-edac";
>> + reg = <0xffc2502c 0x28>;
>> + interrupts = <0 39 4>;
>> + };
>> diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi
>> index 310292e..da0785d 100644
>> --- a/arch/arm/boot/dts/socfpga.dtsi
>> +++ b/arch/arm/boot/dts/socfpga.dtsi
>> @@ -687,6 +687,12 @@
>> reg = <0xffc25000 0x4>;
>> };
>>
>> + sdramedac@ffc2502c {
>> + compatible = "altr,sdram-edac";
>> + reg = <0xffc2502c 0x28>;
>> + interrupts = <0 39 4>;
>> + };
>
> I'm not sure I understand this. The ECC register existing within the
> SDRAM controller, which we have a binding for. Why do we need a separate
> binding for a subset of registers within an IP block?
>
> Why can we not have a single binding for the entire SDRAM controlelr and
> decompse that within Linux as it makes sense for the appropriate
> subsystyems?
>
> Leaking Linux design into bindings is a bad idea; it makes it harder to
> change things.
>
> Mark.

Hi Mark,

How would we decompose this within Linux. MFD? Is there an example
that I can look at?

We originally used syscon for the entire sdram controller register
block but we got dinged on it.

Thanks for your help.

Thor

2014-07-10 20:07:11

by Alan Tull

[permalink] [raw]
Subject: Re: [PATCHv7 2/3] devicetree: Addition of the Altera SDRAM EDAC.

On Wed, Jul 9, 2014 at 3:07 PM, Thor Thayer <[email protected]> wrote:
>
> On Thu, Jun 26, 2014 at 4:45 AM, Mark Rutland <[email protected]> wrote:
> > On Wed, Jun 25, 2014 at 10:15:26PM +0100, [email protected] wrote:
> >> From: Thor Thayer <[email protected]>
> >>
> >> Add the Altera SDRAM EDAC bindings and device tree changes to the Altera SoC project.
> >>
> >> Signed-off-by: Thor Thayer <[email protected]>
> >> ---
> >> v2: Changes to SoC EDAC source code.
> >>
> >> v3: Fix typo in device tree documentation.
> >>
> >> v4,v5: No changes - bump version for consistency.
> >>
> >> v6: Assign ECC registers in SDRAM controller to EDAC
> >>
> >> v7: Fix SDRAM EDAC base address.
> >> ---
> >> .../bindings/arm/altera/socfpga-sdram-edac.txt | 15 +++++++++++++++
> >> arch/arm/boot/dts/socfpga.dtsi | 6 ++++++
> >> 2 files changed, 21 insertions(+)
> >> create mode 100644 Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
> >> new file mode 100644
> >> index 0000000..d68e033
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/arm/altera/socfpga-sdram-edac.txt
> >> @@ -0,0 +1,15 @@
> >> +Altera SOCFPGA SDRAM Error Detection & Correction [EDAC]
> >> +
> >> +Required properties:
> >> +- compatible : should contain "altr,sdram-edac";
> >> +- reg : should contain the ECC register range in sdram
> >> + controller (address and length).
> >> +- interrupts : Should contain the SDRAM ECC IRQ in the
> >> + appropriate format for the IRQ controller.
> >> +
> >> +Example:
> >> + sdramedac@ffc2502c {
> >> + compatible = "altr,sdram-edac";
> >> + reg = <0xffc2502c 0x28>;
> >> + interrupts = <0 39 4>;
> >> + };
> >> diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi
> >> index 310292e..da0785d 100644
> >> --- a/arch/arm/boot/dts/socfpga.dtsi
> >> +++ b/arch/arm/boot/dts/socfpga.dtsi
> >> @@ -687,6 +687,12 @@
> >> reg = <0xffc25000 0x4>;
> >> };
> >>
> >> + sdramedac@ffc2502c {
> >> + compatible = "altr,sdram-edac";
> >> + reg = <0xffc2502c 0x28>;
> >> + interrupts = <0 39 4>;
> >> + };
> >
> > I'm not sure I understand this. The ECC register existing within the
> > SDRAM controller, which we have a binding for. Why do we need a separate
> > binding for a subset of registers within an IP block?
> >
> > Why can we not have a single binding for the entire SDRAM controlelr and
> > decompse that within Linux as it makes sense for the appropriate
> > subsystyems?
> >
> > Leaking Linux design into bindings is a bad idea; it makes it harder to
> > change things.
> >
> > Mark.
>
> Hi Mark,
>
> How would we decompose this within Linux. MFD? Is there an example
> that I can look at?
>
> We originally used syscon for the entire sdram controller register
> block but we got dinged on it.

I think it is good feedback that we don't want the devicetree to break
up this register range (unless someone wants to argue that).

The problem we need to solve here is that the sdram controller
register range has registers that are needed for at least 3 different
functions/drivers: edac, fpga bridges, and loe power mode (putting ddr
in self-refresh). We would not want to do that in one driver.
Originally we had the whole sdram controller as 'syscon' and that was
frowned upon. I think someone suggested a MFD. We can do that and
will do that if that will move things forward. But that would just be
a mfd that ioremaps the range and provides read/write functions for
other drivers to use (which starts looking very similar to syscon
except that it adds more code to the kernel to do what syscon does).
It seems like that's what syscon was for (looking at
Documentation/devicetree/bindings/mfd/syscon.txt).

So can we have a consensus here on syscon or a very minimal mfd or
some other clear way of moving forward?

Alan

>
> Thanks for your help.
>
> Thor