mmc: sdhci-of-ma35d1: Add Nuvoton MA35D1 SDHCI driver

Add the SDHCI driver for the MA35D1 platform. It is based upon the
SDHCI interface, but requires some extra initialization.

Signed-off-by: Shan-Chun Hung <shanchun1218@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20240716004527.20378-3-shanchun1218@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/Kconfig

@@ -252,6 +252,18 @@ config MMC_SDHCI_OF_SPARX5
 
 	  If unsure, say N.
 
+config MMC_SDHCI_OF_MA35D1
+	tristate "SDHCI OF support for the MA35D1 SDHCI controller"
+	depends on ARCH_MA35 || COMPILE_TEST
+	depends on MMC_SDHCI_PLTFM
+	help
+	  This selects the MA35D1 Secure Digital Host Controller Interface.
+	  The controller supports SD/MMC/SDIO devices.
+
+	  If you have a controller with this interface, say Y or M here.
+
+	  If unsure, say N.
+
 config MMC_SDHCI_CADENCE
 	tristate "SDHCI support for the Cadence SD/SDIO/eMMC controller"
 	depends on MMC_SDHCI_PLTFM

drivers/mmc/host/Makefile

@@ -88,6 +88,7 @@ obj-$(CONFIG_MMC_SDHCI_OF_ESDHC)	+= sdhci-of-esdhc.o
 obj-$(CONFIG_MMC_SDHCI_OF_HLWD)		+= sdhci-of-hlwd.o
 obj-$(CONFIG_MMC_SDHCI_OF_DWCMSHC)	+= sdhci-of-dwcmshc.o
 obj-$(CONFIG_MMC_SDHCI_OF_SPARX5)	+= sdhci-of-sparx5.o
+obj-$(CONFIG_MMC_SDHCI_OF_MA35D1)	+= sdhci-of-ma35d1.o
 obj-$(CONFIG_MMC_SDHCI_BCM_KONA)	+= sdhci-bcm-kona.o
 obj-$(CONFIG_MMC_SDHCI_IPROC)		+= sdhci-iproc.o
 obj-$(CONFIG_MMC_SDHCI_NPCM)		+= sdhci-npcm.o

drivers/mmc/host/sdhci-of-ma35d1.c

@@ -0,0 +1,314 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ *
+ * Author: Shan-Chun Hung <shanchun1218@gmail.com>
+ */
+
+#include <linux/align.h>
+#include <linux/array_size.h>
+#include <linux/bits.h>
+#include <linux/build_bug.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dev_printk.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/math.h>
+#include <linux/mfd/syscon.h>
+#include <linux/minmax.h>
+#include <linux/mmc/card.h>
+#include <linux/mmc/host.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/sizes.h>
+#include <linux/types.h>
+
+#include "sdhci-pltfm.h"
+#include "sdhci.h"
+
+#define MA35_SYS_MISCFCR0	0x070
+#define MA35_SDHCI_MSHCCTL	0x508
+#define MA35_SDHCI_MBIUCTL	0x510
+
+#define MA35_SDHCI_CMD_CONFLICT_CHK	BIT(0)
+#define MA35_SDHCI_INCR_MSK		GENMASK(3, 0)
+#define MA35_SDHCI_INCR16		BIT(3)
+#define MA35_SDHCI_INCR8		BIT(2)
+
+struct ma35_priv {
+	struct reset_control	*rst;
+	struct pinctrl		*pinctrl;
+	struct pinctrl_state	*pins_uhs;
+	struct pinctrl_state	*pins_default;
+};
+
+struct ma35_restore_data {
+	u32	reg;
+	u32	width;
+};
+
+static const struct ma35_restore_data restore_data[] = {
+	{ SDHCI_CLOCK_CONTROL,		sizeof(u32)},
+	{ SDHCI_BLOCK_SIZE,		sizeof(u32)},
+	{ SDHCI_INT_ENABLE,		sizeof(u32)},
+	{ SDHCI_SIGNAL_ENABLE,		sizeof(u32)},
+	{ SDHCI_AUTO_CMD_STATUS,	sizeof(u32)},
+	{ SDHCI_HOST_CONTROL,		sizeof(u32)},
+	{ SDHCI_TIMEOUT_CONTROL,	sizeof(u8) },
+	{ MA35_SDHCI_MSHCCTL,		sizeof(u16)},
+	{ MA35_SDHCI_MBIUCTL,		sizeof(u16)},
+};
+
+/*
+ * If DMA addr spans 128MB boundary, we split the DMA transfer into two
+ * so that each DMA transfer doesn't exceed the boundary.
+ */
+static void ma35_adma_write_desc(struct sdhci_host *host, void **desc, dma_addr_t addr, int len,
+				 unsigned int cmd)
+{
+	int tmplen, offset;
+
+	if (likely(!len || (ALIGN(addr, SZ_128M) == ALIGN(addr + len - 1, SZ_128M)))) {
+		sdhci_adma_write_desc(host, desc, addr, len, cmd);
+		return;
+	}
+
+	offset = addr & (SZ_128M - 1);
+	tmplen = SZ_128M - offset;
+	sdhci_adma_write_desc(host, desc, addr, tmplen, cmd);
+
+	addr += tmplen;
+	len -= tmplen;
+	sdhci_adma_write_desc(host, desc, addr, len, cmd);
+}
+
+static void ma35_set_clock(struct sdhci_host *host, unsigned int clock)
+{
+	u32 ctl;
+
+	/*
+	 * If the clock frequency exceeds MMC_HIGH_52_MAX_DTR,
+	 * disable command conflict check.
+	 */
+	ctl = sdhci_readw(host, MA35_SDHCI_MSHCCTL);
+	if (clock > MMC_HIGH_52_MAX_DTR)
+		ctl &= ~MA35_SDHCI_CMD_CONFLICT_CHK;
+	else
+		ctl |= MA35_SDHCI_CMD_CONFLICT_CHK;
+	sdhci_writew(host, ctl, MA35_SDHCI_MSHCCTL);
+
+	sdhci_set_clock(host, clock);
+}
+
+static int ma35_start_signal_voltage_switch(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+	struct sdhci_host *host = mmc_priv(mmc);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct ma35_priv *priv = sdhci_pltfm_priv(pltfm_host);
+
+	switch (ios->signal_voltage) {
+	case MMC_SIGNAL_VOLTAGE_180:
+		if (!IS_ERR(priv->pinctrl) && !IS_ERR(priv->pins_uhs))
+			pinctrl_select_state(priv->pinctrl, priv->pins_uhs);
+		break;
+	case MMC_SIGNAL_VOLTAGE_330:
+		if (!IS_ERR(priv->pinctrl) && !IS_ERR(priv->pins_default))
+			pinctrl_select_state(priv->pinctrl, priv->pins_default);
+		break;
+	default:
+		dev_err(mmc_dev(host->mmc), "Unsupported signal voltage!\n");
+		return -EINVAL;
+	}
+
+	return sdhci_start_signal_voltage_switch(mmc, ios);
+}
+
+static void ma35_voltage_switch(struct sdhci_host *host)
+{
+	/* Wait for 5ms after set 1.8V signal enable bit */
+	fsleep(5000);
+}
+
+static int ma35_execute_tuning(struct mmc_host *mmc, u32 opcode)
+{
+	struct sdhci_host *host = mmc_priv(mmc);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct ma35_priv *priv = sdhci_pltfm_priv(pltfm_host);
+	int idx;
+	u32 regs[ARRAY_SIZE(restore_data)] = {};
+
+	/*
+	 * Limitations require a reset of SD/eMMC before tuning and
+	 * saving the registers before resetting, then restoring
+	 * after the reset.
+	 */
+	for (idx = 0; idx < ARRAY_SIZE(restore_data); idx++) {
+		if (restore_data[idx].width == sizeof(u32))
+			regs[idx] = sdhci_readl(host, restore_data[idx].reg);
+		else if (restore_data[idx].width == sizeof(u16))
+			regs[idx] = sdhci_readw(host, restore_data[idx].reg);
+		else if (restore_data[idx].width == sizeof(u8))
+			regs[idx] = sdhci_readb(host, restore_data[idx].reg);
+	}
+
+	reset_control_assert(priv->rst);
+	reset_control_deassert(priv->rst);
+
+	for (idx = 0; idx < ARRAY_SIZE(restore_data); idx++) {
+		if (restore_data[idx].width == sizeof(u32))
+			sdhci_writel(host, regs[idx], restore_data[idx].reg);
+		else if (restore_data[idx].width == sizeof(u16))
+			sdhci_writew(host, regs[idx], restore_data[idx].reg);
+		else if (restore_data[idx].width == sizeof(u8))
+			sdhci_writeb(host, regs[idx], restore_data[idx].reg);
+	}
+
+	return sdhci_execute_tuning(mmc, opcode);
+}
+
+static const struct sdhci_ops sdhci_ma35_ops = {
+	.set_clock		= ma35_set_clock,
+	.set_bus_width		= sdhci_set_bus_width,
+	.set_uhs_signaling	= sdhci_set_uhs_signaling,
+	.get_max_clock		= sdhci_pltfm_clk_get_max_clock,
+	.reset			= sdhci_reset,
+	.adma_write_desc	= ma35_adma_write_desc,
+	.voltage_switch		= ma35_voltage_switch,
+};
+
+static const struct sdhci_pltfm_data sdhci_ma35_pdata = {
+	.ops = &sdhci_ma35_ops,
+	.quirks = SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
+	.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN | SDHCI_QUIRK2_BROKEN_DDR50 |
+		   SDHCI_QUIRK2_ACMD23_BROKEN,
+};
+
+static int ma35_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct sdhci_pltfm_host *pltfm_host;
+	struct sdhci_host *host;
+	struct ma35_priv *priv;
+	int err;
+	u32 extra, ctl;
+
+	host = sdhci_pltfm_init(pdev, &sdhci_ma35_pdata, sizeof(struct ma35_priv));
+	if (IS_ERR(host))
+		return PTR_ERR(host);
+
+	/* Extra adma table cnt for cross 128M boundary handling. */
+	extra = DIV_ROUND_UP_ULL(dma_get_required_mask(dev), SZ_128M);
+	extra = min(extra, SDHCI_MAX_SEGS);
+
+	host->adma_table_cnt += extra;
+	pltfm_host = sdhci_priv(host);
+	priv = sdhci_pltfm_priv(pltfm_host);
+
+	pltfm_host->clk = devm_clk_get_optional_enabled(dev, NULL);
+	if (IS_ERR(pltfm_host->clk)) {
+		err = dev_err_probe(dev, PTR_ERR(pltfm_host->clk), "failed to get clk\n");
+		goto err_sdhci;
+	}
+
+	err = mmc_of_parse(host->mmc);
+	if (err)
+		goto err_sdhci;
+
+	priv->rst = devm_reset_control_get_exclusive(dev, NULL);
+	if (IS_ERR(priv->rst)) {
+		err = dev_err_probe(dev, PTR_ERR(priv->rst), "failed to get reset control\n");
+		goto err_sdhci;
+	}
+
+	sdhci_get_of_property(pdev);
+
+	priv->pinctrl = devm_pinctrl_get(dev);
+	if (!IS_ERR(priv->pinctrl)) {
+		priv->pins_default = pinctrl_lookup_state(priv->pinctrl, "default");
+		priv->pins_uhs = pinctrl_lookup_state(priv->pinctrl, "state_uhs");
+		pinctrl_select_state(priv->pinctrl, priv->pins_default);
+	}
+
+	if (!(host->quirks2 & SDHCI_QUIRK2_NO_1_8_V)) {
+		struct regmap	*regmap;
+		u32		reg;
+
+		regmap = syscon_regmap_lookup_by_phandle(dev_of_node(dev), "nuvoton,sys");
+		if (!IS_ERR(regmap)) {
+			/* Enable SDHCI voltage stable for 1.8V */
+			regmap_read(regmap, MA35_SYS_MISCFCR0, &reg);
+			reg |= BIT(17);
+			regmap_write(regmap, MA35_SYS_MISCFCR0, reg);
+		}
+
+		host->mmc_host_ops.start_signal_voltage_switch =
+					ma35_start_signal_voltage_switch;
+	}
+
+	host->mmc_host_ops.execute_tuning = ma35_execute_tuning;
+
+	err = sdhci_add_host(host);
+	if (err)
+		goto err_sdhci;
+
+	/*
+	 * Split data into chunks of 16 or 8 bytes for transmission.
+	 * Each chunk transfer is guaranteed to be uninterrupted on the bus.
+	 * This likely corresponds to the AHB bus DMA burst size.
+	 */
+	ctl = sdhci_readw(host, MA35_SDHCI_MBIUCTL);
+	ctl &= ~MA35_SDHCI_INCR_MSK;
+	ctl |= MA35_SDHCI_INCR16 | MA35_SDHCI_INCR8;
+	sdhci_writew(host, ctl, MA35_SDHCI_MBIUCTL);
+
+	return 0;
+
+err_sdhci:
+	sdhci_pltfm_free(pdev);
+	return err;
+}
+
+static void ma35_disable_card_clk(struct sdhci_host *host)
+{
+	u16 ctrl;
+
+	ctrl = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
+	if (ctrl & SDHCI_CLOCK_CARD_EN) {
+		ctrl &= ~SDHCI_CLOCK_CARD_EN;
+		sdhci_writew(host, ctrl, SDHCI_CLOCK_CONTROL);
+	}
+}
+
+static void ma35_remove(struct platform_device *pdev)
+{
+	struct sdhci_host *host = platform_get_drvdata(pdev);
+
+	sdhci_remove_host(host, 0);
+	ma35_disable_card_clk(host);
+	sdhci_pltfm_free(pdev);
+}
+
+static const struct of_device_id sdhci_ma35_dt_ids[] = {
+	{ .compatible = "nuvoton,ma35d1-sdhci" },
+	{}
+};
+
+static struct platform_driver sdhci_ma35_driver = {
+	.driver	= {
+		.name	= "sdhci-ma35",
+		.of_match_table = sdhci_ma35_dt_ids,
+	},
+	.probe	= ma35_probe,
+	.remove_new = ma35_remove,
+};
+module_platform_driver(sdhci_ma35_driver);
+
+MODULE_DESCRIPTION("SDHCI platform driver for Nuvoton MA35");
+MODULE_AUTHOR("Shan-Chun Hung <shanchun1218@gmail.com>");
+MODULE_LICENSE("GPL");