Received-SPF: Pass (protection.outlook.com: domain of amd.com designates
 165.204.84.17 as permitted sender) receiver=protection.outlook.com;
 client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C
From:   Brad Larson <blarson@amd.com>
To:     <linux-arm-kernel@lists.infradead.org>
CC:     <linux-kernel@vger.kernel.org>, <linux-mmc@vger.kernel.org>,
        <linux-spi@vger.kernel.org>, <adrian.hunter@intel.com>,
        <alcooperx@gmail.com>, <andy.shevchenko@gmail.com>,
        <arnd@arndb.de>, <blarson@amd.com>, <brendan.higgins@linux.dev>,
        <briannorris@chromium.org>, <brijeshkumar.singh@amd.com>,
        <catalin.marinas@arm.com>, <davidgow@google.com>,
        <gsomlo@gmail.com>, <gerg@linux-m68k.org>, <krzk@kernel.org>,
        <krzysztof.kozlowski+dt@linaro.org>, <lee@kernel.org>,
        <lee.jones@linaro.org>, <broonie@kernel.org>,
        <yamada.masahiro@socionext.com>, <p.zabel@pengutronix.de>,
        <piotrs@cadence.com>, <p.yadav@ti.com>, <rdunlap@infradead.org>,
        <robh+dt@kernel.org>, <samuel@sholland.org>,
        <fancer.lancer@gmail.com>, <skhan@linuxfoundation.org>,
        <suravee.suthikulpanit@amd.com>, <thomas.lendacky@amd.com>,
        <tonyhuang.sunplus@gmail.com>, <ulf.hansson@linaro.org>,
        <vaishnav.a@ti.com>, <will@kernel.org>,
        <devicetree@vger.kernel.org>
Subject: [PATCH v11 13/15] mmc: sdhci-cadence: Add AMD Pensando Elba SoC support
Date:   Sat, 11 Mar 2023 16:44:43 -0800
Message-ID: <20230312004445.15913-14-blarson@amd.com>
In-Reply-To: <20230312004445.15913-1-blarson@amd.com>
References: <20230312004445.15913-1-blarson@amd.com>
MIME-Version: 1.0
Content-Type: text/plain
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Mar 2023 00:47:08.0776
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: b3fa9872-e447-4905-d0c9-08db22934eda
X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com]
X-MS-Exchange-CrossTenant-AuthSource: DM6NAM11FT018.eop-nam11.prod.protection.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Anonymous
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH3PR12MB7546
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Add support for AMD Pensando Elba SoC which explicitly
controls byte-lane enables on writes.

Select MMC_SDHCI_IO_ACCESSORS for MMC_SDHCI_CADENCE which
allows Elba SoC sdhci_elba_ops to overwrite the SDHCI
IO memory accessors

Signed-off-by: Brad Larson <blarson@amd.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
---

v11 changes:
- Remove elba-drv_init() call to platform_get_resource() since that
  check is done inside devm_platform_ioremap_resource()
- Move spin_lock_init() before error check
- Remove extra parentheses

v10 changes:
- Add Elba specific support into this 3rd patch.  This builds on the private
  writel() enabled in patch 1 followed by platform specific init() in patch 2.
- Specify when first used the reason for the spinlock use to order byte-enable
  prior to write data.

---
 drivers/mmc/host/Kconfig         |  1 +
 drivers/mmc/host/sdhci-cadence.c | 96 ++++++++++++++++++++++++++++++++
 2 files changed, 97 insertions(+)

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 4745fe217ade..9f793892123c 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -255,6 +255,7 @@ config MMC_SDHCI_CADENCE
 	tristate "SDHCI support for the Cadence SD/SDIO/eMMC controller"
 	depends on MMC_SDHCI_PLTFM
 	depends on OF
+	select MMC_SDHCI_IO_ACCESSORS
 	help
 	  This selects the Cadence SD/SDIO/eMMC driver.
 
diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c
index c528a25f48b8..c0024d1e69a8 100644
--- a/drivers/mmc/host/sdhci-cadence.c
+++ b/drivers/mmc/host/sdhci-cadence.c
@@ -66,6 +66,8 @@ struct sdhci_cdns_phy_param {
 
 struct sdhci_cdns_priv {
 	void __iomem *hrs_addr;
+	void __iomem *ctl_addr;	/* write control */
+	spinlock_t wrlock;	/* write lock */
 	bool enhanced_strobe;
 	void (*priv_writel)(struct sdhci_cdns_priv *priv, u32 val, void __iomem *reg);
 	unsigned int nr_phy_params;
@@ -321,6 +323,89 @@ static void sdhci_cdns_set_uhs_signaling(struct sdhci_host *host,
 		sdhci_set_uhs_signaling(host, timing);
 }
 
+/* Elba control register bits [6:3] are byte-lane enables */
+#define ELBA_BYTE_ENABLE_MASK(x)	((x) << 3)
+
+/*
+ * The Pensando Elba SoC explicitly controls byte-lane enabling on writes
+ * which includes writes to the HRS registers.  The write lock (wrlock)
+ * is used to ensure byte-lane enable, using write control (ctl_addr),
+ * occurs before the data write.
+ */
+static void elba_priv_writel(struct sdhci_cdns_priv *priv, u32 val,
+			     void __iomem *reg)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->wrlock, flags);
+	writel(ELBA_BYTE_ENABLE_MASK(0xf), priv->ctl_addr);
+	writel(val, reg);
+	spin_unlock_irqrestore(&priv->wrlock, flags);
+}
+
+static void elba_write_l(struct sdhci_host *host, u32 val, int reg)
+{
+	elba_priv_writel(sdhci_cdns_priv(host), val, host->ioaddr + reg);
+}
+
+static void elba_write_w(struct sdhci_host *host, u16 val, int reg)
+{
+	struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
+	u32 byte_enables;
+	unsigned long flags;
+
+	byte_enables = GENMASK(1, 0) << (reg & 0x3);
+	spin_lock_irqsave(&priv->wrlock, flags);
+	writel(ELBA_BYTE_ENABLE_MASK(byte_enables), priv->ctl_addr);
+	writew(val, host->ioaddr + reg);
+	spin_unlock_irqrestore(&priv->wrlock, flags);
+}
+
+static void elba_write_b(struct sdhci_host *host, u8 val, int reg)
+{
+	struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
+	u32 byte_enables;
+	unsigned long flags;
+
+	byte_enables = BIT(0) << (reg & 0x3);
+	spin_lock_irqsave(&priv->wrlock, flags);
+	writel(ELBA_BYTE_ENABLE_MASK(byte_enables), priv->ctl_addr);
+	writeb(val, host->ioaddr + reg);
+	spin_unlock_irqrestore(&priv->wrlock, flags);
+}
+
+static const struct sdhci_ops sdhci_elba_ops = {
+	.write_l = elba_write_l,
+	.write_w = elba_write_w,
+	.write_b = elba_write_b,
+	.set_clock = sdhci_set_clock,
+	.get_timeout_clock = sdhci_cdns_get_timeout_clock,
+	.set_bus_width = sdhci_set_bus_width,
+	.reset = sdhci_reset,
+	.set_uhs_signaling = sdhci_cdns_set_uhs_signaling,
+};
+
+static int elba_drv_init(struct platform_device *pdev)
+{
+	struct sdhci_host *host = platform_get_drvdata(pdev);
+	struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
+	void __iomem *ioaddr;
+
+	host->mmc->caps |= MMC_CAP_1_8V_DDR | MMC_CAP_8_BIT_DATA;
+	spin_lock_init(&priv->wrlock);
+
+	/* Byte-lane control register */
+	ioaddr = devm_platform_ioremap_resource(pdev, 1);
+	if (IS_ERR(ioaddr))
+		return PTR_ERR(ioaddr);
+
+	priv->ctl_addr = ioaddr;
+	priv->priv_writel = elba_priv_writel;
+	writel(ELBA_BYTE_ENABLE_MASK(0xf), priv->ctl_addr);
+
+	return 0;
+}
+
 static const struct sdhci_ops sdhci_cdns_ops = {
 	.set_clock = sdhci_set_clock,
 	.get_timeout_clock = sdhci_cdns_get_timeout_clock,
@@ -337,6 +422,13 @@ static const struct sdhci_cdns_drv_data sdhci_cdns_uniphier_drv_data = {
 	},
 };
 
+static const struct sdhci_cdns_drv_data sdhci_elba_drv_data = {
+	.init = elba_drv_init,
+	.pltfm_data = {
+		.ops = &sdhci_elba_ops,
+	},
+};
+
 static const struct sdhci_cdns_drv_data sdhci_cdns_drv_data = {
 	.pltfm_data = {
 		.ops = &sdhci_cdns_ops,
@@ -477,6 +569,10 @@ static const struct of_device_id sdhci_cdns_match[] = {
 		.compatible = "socionext,uniphier-sd4hc",
 		.data = &sdhci_cdns_uniphier_drv_data,
 	},
+	{
+		.compatible = "amd,pensando-elba-sd4hc",
+		.data = &sdhci_elba_drv_data,
+	},
 	{ .compatible = "cdns,sd4hc" },
 	{ /* sentinel */ }
 };
-- 
2.17.1