[PATCH V4 6/7] mmc: sdhci-sprd: added Spreadtrum's initial host controller

[Chunyan Zhang]

From: Chunyan Zhang <chunyan.zhang@xxxxxxxxxxxxxx>

This patch adds the initial support of Secure Digital Host Controller
Interface compliant controller found in some latest Spreadtrum chipsets.
This patch has been tested on the version of SPRD-R11 controller.

R11 is a variant based on SD v4.0 specification.

With this driver, R11 mmc can be initialized, can be mounted, read and
written.

Original-by: Billows Wu <billows.wu@xxxxxxxxxxxxxx>
Signed-off-by: Chunyan Zhang <chunyan.zhang@xxxxxxxxxxxxxx>
---
 drivers/mmc/host/Kconfig      |  13 ++
 drivers/mmc/host/Makefile     |   1 +
 drivers/mmc/host/sdhci-sprd.c | 455 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 469 insertions(+)
 create mode 100644 drivers/mmc/host/sdhci-sprd.c

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 0581c19..c5424dc 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -581,6 +581,19 @@ config MMC_SDRICOH_CS
 	  To compile this driver as a module, choose M here: the
 	  module will be called sdricoh_cs.
 
+config MMC_SDHCI_SPRD
+	tristate "Spreadtrum SDIO host Controller"
+	depends on ARCH_SPRD
+	depends on MMC_SDHCI_PLTFM
+	select MMC_SDHCI_IO_ACCESSORS
+	help
+	  This selects the SDIO Host Controller in Spreadtrum
+	  SoCs, this driver supports R11(IP version: R11P0).
+
+	  If you have a controller with this interface, say Y or M here.
+
+	  If unsure, say N.
+
 config MMC_TMIO_CORE
 	tristate
 
diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index 85dc132..b0b6802 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -89,6 +89,7 @@ obj-$(CONFIG_MMC_SDHCI_ST)		+= sdhci-st.o
 obj-$(CONFIG_MMC_SDHCI_MICROCHIP_PIC32)	+= sdhci-pic32.o
 obj-$(CONFIG_MMC_SDHCI_BRCMSTB)		+= sdhci-brcmstb.o
 obj-$(CONFIG_MMC_SDHCI_OMAP)		+= sdhci-omap.o
+obj-$(CONFIG_MMC_SDHCI_SPRD)		+= sdhci-sprd.o
 obj-$(CONFIG_MMC_CQHCI)			+= cqhci.o
 
 ifeq ($(CONFIG_CB710_DEBUG),y)
diff --git a/drivers/mmc/host/sdhci-sprd.c b/drivers/mmc/host/sdhci-sprd.c
new file mode 100644
index 0000000..b467ed5
--- /dev/null
+++ b/drivers/mmc/host/sdhci-sprd.c
@@ -0,0 +1,455 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Secure Digital Host Controller
+//
+// Copyright (C) 2018 Spreadtrum, Inc.
+// Author: Chunyan Zhang <chunyan.zhang@xxxxxxxxxxxxxx>
+
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/highmem.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+#include "sdhci-pltfm.h"
+
+#define SDHCI_SPRD_REG_32_DLL_DLY_OFFSET	0x208
+#define  SDHCIBSPRD_IT_WR_DLY_INV		BIT(5)
+#define  SDHCI_SPRD_BIT_CMD_DLY_INV		BIT(13)
+#define  SDHCI_SPRD_BIT_POSRD_DLY_INV		BIT(21)
+#define  SDHCI_SPRD_BIT_NEGRD_DLY_INV		BIT(29)
+
+#define SDHCI_SPRD_REG_32_BUSY_POSI		0x250
+#define  SDHCI_SPRD_BIT_OUTR_CLK_AUTO_EN	BIT(25)
+#define  SDHCI_SPRD_BIT_INNR_CLK_AUTO_EN	BIT(24)
+
+#define SDHCI_SPRD_REG_DEBOUNCE		0x28C
+#define  SDHCI_SPRD_BIT_DLL_BAK		BIT(0)
+#define  SDHCI_SPRD_BIT_DLL_VAL		BIT(1)
+
+#define  SDHCI_SPRD_INT_SIGNAL_MASK	0x1B7F410B
+
+/* SDHCI_HOST_CONTROL2 */
+#define  SDHCI_SPRD_CTRL_HS200		0x0005
+#define  SDHCI_SPRD_CTRL_HS400		0x0006
+
+/*
+ * According to the standard specification, BIT(3) of SDHCI_SOFTWARE_RESET is
+ * reserved, and only used on Spreadtrum's design, the hardware cannot work
+ * if this bit is cleared.
+ * 1 : normal work
+ * 0 : hardware reset
+ */
+#define  SDHCI_HW_RESET_CARD		BIT(3)
+
+#define SDHCI_SPRD_MAX_CUR		0xFFFFFF
+#define SDHCI_SPRD_CLK_MAX_DIV		1023
+
+#define SDHCI_SPRD_CLK_DEF_RATE		26000000
+
+struct sdhci_sprd_host {
+	u32 version;
+	struct clk *clk_sdio;
+	struct clk *clk_enable;
+	u32 base_rate;
+};
+
+#define TO_SPRD_HOST(host) sdhci_pltfm_priv(sdhci_priv(host))
+
+static void sdhci_sprd_init_config(struct sdhci_host *host)
+{
+	u16 val;
+
+	/* set dll backup mode */
+	val = sdhci_readl(host, SDHCI_SPRD_REG_DEBOUNCE);
+	val |= SDHCI_SPRD_BIT_DLL_BAK | SDHCI_SPRD_BIT_DLL_VAL;
+	sdhci_writel(host, val, SDHCI_SPRD_REG_DEBOUNCE);
+}
+
+static inline u32 sdhci_sprd_readl(struct sdhci_host *host, int reg)
+{
+	if (unlikely(reg == SDHCI_MAX_CURRENT))
+		return SDHCI_SPRD_MAX_CUR;
+
+	return readl_relaxed(host->ioaddr + reg);
+}
+
+static inline void sdhci_sprd_writel(struct sdhci_host *host, u32 val, int reg)
+{
+	/* SDHCI_MAX_CURRENT is reserved on Spreadtrum's platform */
+	if (unlikely(reg == SDHCI_MAX_CURRENT))
+		return;
+
+	if (unlikely(reg == SDHCI_SIGNAL_ENABLE || reg == SDHCI_INT_ENABLE))
+		val = val & SDHCI_SPRD_INT_SIGNAL_MASK;
+
+	writel_relaxed(val, host->ioaddr + reg);
+}
+
+static inline void sdhci_sprd_writeb(struct sdhci_host *host, u8 val, int reg)
+{
+	/*
+	 * Since BIT(3) of SDHCI_SOFTWARE_RESET is reserved according to the
+	 * standard specification, sdhci_reset() write this register directly
+	 * without checking other reserved bits, that will clear BIT(3) which
+	 * is defined as hardware reset on Spreadtrum's platform and clearing
+	 * it by mistake will lead the card not work. So here we need to work
+	 * around it.
+	 */
+	if (unlikely(reg == SDHCI_SOFTWARE_RESET)) {
+		if (readb_relaxed(host->ioaddr + reg) & SDHCI_HW_RESET_CARD)
+			val |= SDHCI_HW_RESET_CARD;
+	}
+
+	writeb_relaxed(val, host->ioaddr + reg);
+}
+
+static inline void sdhci_sprd_sd_clk_off(struct sdhci_host *host)
+{
+	u16 ctrl = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
+
+	ctrl &= ~SDHCI_CLOCK_CARD_EN;
+	sdhci_writew(host, ctrl, SDHCI_CLOCK_CONTROL);
+}
+
+static inline void
+sdhci_sprd_set_dll_invert(struct sdhci_host *host, u32 mask, bool en)
+{
+	u32 dll_dly_offset;
+
+	dll_dly_offset = sdhci_readl(host, SDHCI_SPRD_REG_32_DLL_DLY_OFFSET);
+	if (en)
+		dll_dly_offset |= mask;
+	else
+		dll_dly_offset &= ~mask;
+	sdhci_writel(host, dll_dly_offset, SDHCI_SPRD_REG_32_DLL_DLY_OFFSET);
+}
+
+static inline u32 sdhci_sprd_calc_div(u32 base_clk, u32 clk)
+{
+	u32 div;
+
+	/* select 2x clock source */
+	if (base_clk <= clk * 2)
+		return 0;
+
+	div = (u32) (base_clk / (clk * 2));
+
+	if ((base_clk / div) > (clk * 2))
+		div++;
+
+	if (div > SDHCI_SPRD_CLK_MAX_DIV)
+		div = SDHCI_SPRD_CLK_MAX_DIV;
+
+	if (div % 2)
+		div = (div + 1) / 2;
+	else
+		div = div / 2;
+
+	return div;
+}
+
+static inline void _sdhci_sprd_set_clock(struct sdhci_host *host,
+					unsigned int clk)
+{
+	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);
+	u32 div, val, mask;
+
+	div = sdhci_sprd_calc_div(sprd_host->base_rate, clk);
+
+	clk |= ((div & 0x300) >> 2) | ((div & 0xFF) << 8);
+	sdhci_enable_clk(host, clk);
+
+	/* enable auto gate sdhc_enable_auto_gate */
+	val = sdhci_readl(host, SDHCI_SPRD_REG_32_BUSY_POSI);
+	mask = SDHCI_SPRD_BIT_OUTR_CLK_AUTO_EN |
+	       SDHCI_SPRD_BIT_INNR_CLK_AUTO_EN;
+	if (mask != (val & mask)) {
+		val |= mask;
+		sdhci_writel(host, val, SDHCI_SPRD_REG_32_BUSY_POSI);
+	}
+}
+
+static void sdhci_sprd_set_clock(struct sdhci_host *host, unsigned int clock)
+{
+	bool en = false;
+
+	if (clock == 0) {
+		sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
+	} else if (clock != host->clock) {
+		sdhci_sprd_sd_clk_off(host);
+		_sdhci_sprd_set_clock(host, clock);
+
+		if (clock <= 400000)
+			en = true;
+		sdhci_sprd_set_dll_invert(host, SDHCI_SPRD_BIT_CMD_DLY_INV |
+					  SDHCI_SPRD_BIT_POSRD_DLY_INV, en);
+	} else {
+		_sdhci_sprd_set_clock(host, clock);
+	}
+}
+
+static unsigned int sdhci_sprd_get_max_clock(struct sdhci_host *host)
+{
+	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);
+
+	return clk_round_rate(sprd_host->clk_sdio, ULONG_MAX);
+}
+
+static unsigned int sdhci_sprd_get_min_clock(struct sdhci_host *host)
+{
+	return 400000;
+}
+
+static void sdhci_sprd_set_uhs_signaling(struct sdhci_host *host,
+					 unsigned int timing)
+{
+	u16 ctrl_2;
+
+	if (timing == host->timing)
+		return;
+
+	ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+	/* Select Bus Speed Mode for host */
+	ctrl_2 &= ~SDHCI_CTRL_UHS_MASK;
+	switch (timing) {
+	case MMC_TIMING_UHS_SDR12:
+		ctrl_2 |= SDHCI_CTRL_UHS_SDR12;
+		break;
+	case MMC_TIMING_MMC_HS:
+	case MMC_TIMING_SD_HS:
+	case MMC_TIMING_UHS_SDR25:
+		ctrl_2 |= SDHCI_CTRL_UHS_SDR25;
+		break;
+	case MMC_TIMING_UHS_SDR50:
+		ctrl_2 |= SDHCI_CTRL_UHS_SDR50;
+		break;
+	case MMC_TIMING_UHS_SDR104:
+		ctrl_2 |= SDHCI_CTRL_UHS_SDR104;
+		break;
+	case MMC_TIMING_UHS_DDR50:
+	case MMC_TIMING_MMC_DDR52:
+		ctrl_2 |= SDHCI_CTRL_UHS_DDR50;
+		break;
+	case MMC_TIMING_MMC_HS200:
+		ctrl_2 |= SDHCI_SPRD_CTRL_HS200;
+		break;
+	case MMC_TIMING_MMC_HS400:
+		ctrl_2 |= SDHCI_SPRD_CTRL_HS400;
+		break;
+	default:
+		break;
+	}
+
+	sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
+}
+
+static void sdhci_sprd_hw_reset(struct sdhci_host *host)
+{
+	int val;
+
+	/*
+	 * Note: don't use sdhci_writeb() API here since it is redirected to
+	 * sdhci_sprd_writeb() in which we have a workaround for
+	 * SDHCI_SOFTWARE_RESET which would make bit SDHCI_HW_RESET_CARD can
+	 * not be cleared.
+	 */
+	val = readb_relaxed(host->ioaddr + SDHCI_SOFTWARE_RESET);
+	val &= ~SDHCI_HW_RESET_CARD;
+	writeb_relaxed(val, host->ioaddr + SDHCI_SOFTWARE_RESET);
+	/* wait for 10 us */
+	usleep_range(10, 20);
+
+	val |= SDHCI_HW_RESET_CARD;
+	writeb_relaxed(val, host->ioaddr + SDHCI_SOFTWARE_RESET);
+	usleep_range(300, 500);
+}
+
+static struct sdhci_ops sdhci_sprd_ops = {
+	.read_l = sdhci_sprd_readl,
+	.write_l = sdhci_sprd_writel,
+	.write_b = sdhci_sprd_writeb,
+	.set_clock = sdhci_sprd_set_clock,
+	.get_max_clock = sdhci_sprd_get_max_clock,
+	.get_min_clock = sdhci_sprd_get_min_clock,
+	.set_bus_width = sdhci_set_bus_width,
+	.reset = sdhci_reset,
+	.set_uhs_signaling = sdhci_sprd_set_uhs_signaling,
+	.hw_reset = sdhci_sprd_hw_reset,
+};
+
+static const struct sdhci_pltfm_data sdhci_sprd_pdata = {
+	.quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK,
+	.quirks2 = SDHCI_QUIRK2_BROKEN_HS200,
+	.ops = &sdhci_sprd_ops,
+};
+
+static int sdhci_sprd_probe(struct platform_device *pdev)
+{
+	struct sdhci_host *host;
+	struct sdhci_sprd_host *sprd_host;
+	struct clk *clk;
+	int ret = 0;
+
+	host = sdhci_pltfm_init(pdev, &sdhci_sprd_pdata, sizeof(*sprd_host));
+	if (IS_ERR(host))
+		return PTR_ERR(host);
+
+	host->dma_mask = DMA_BIT_MASK(64);
+	pdev->dev.dma_mask = &host->dma_mask;
+
+	host->mmc->caps = MMC_CAP_SD_HIGHSPEED | MMC_CAP_MMC_HIGHSPEED |
+		MMC_CAP_ERASE | MMC_CAP_CMD23;
+	ret = mmc_of_parse(host->mmc);
+	if (ret)
+		goto pltfm_free;
+
+	sprd_host = TO_SPRD_HOST(host);
+
+	clk = devm_clk_get(&pdev->dev, "sdio");
+	if (IS_ERR(clk)) {
+		ret = PTR_ERR(clk);
+		goto pltfm_free;
+	}
+	sprd_host->clk_sdio = clk;
+	sprd_host->base_rate = clk_get_rate(sprd_host->clk_sdio);
+	if (!sprd_host->base_rate)
+		sprd_host->base_rate = SDHCI_SPRD_CLK_DEF_RATE;
+
+	clk = devm_clk_get(&pdev->dev, "enable");
+	if (IS_ERR(clk)) {
+		ret = PTR_ERR(clk);
+		goto pltfm_free;
+	}
+	sprd_host->clk_enable = clk;
+
+	ret = clk_prepare_enable(sprd_host->clk_sdio);
+	if (ret)
+		goto pltfm_free;
+
+	clk_prepare_enable(sprd_host->clk_enable);
+	if (ret)
+		goto clk_disable;
+
+	sdhci_sprd_init_config(host);
+	host->version = sdhci_readw(host, SDHCI_HOST_VERSION);
+	sprd_host->version = ((host->version & SDHCI_VENDOR_VER_MASK) >>
+			       SDHCI_VENDOR_VER_SHIFT);
+
+	pm_runtime_get_noresume(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_suspend_ignore_children(&pdev->dev, 1);
+
+	sdhci_enable_v4_mode(host);
+	ret = sdhci_add_host(host);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to add mmc host: %d\n", ret);
+		goto pm_runtime_disable;
+	}
+
+	pm_runtime_mark_last_busy(&pdev->dev);
+	pm_runtime_put_autosuspend(&pdev->dev);
+
+	return 0;
+
+pm_runtime_disable:
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+
+	clk_disable_unprepare(sprd_host->clk_enable);
+
+clk_disable:
+	clk_disable_unprepare(sprd_host->clk_sdio);
+
+pltfm_free:
+	sdhci_pltfm_free(pdev);
+	return ret;
+}
+
+static int sdhci_sprd_remove(struct platform_device *pdev)
+{
+	struct sdhci_host *host = platform_get_drvdata(pdev);
+	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);
+	struct mmc_host *mmc = host->mmc;
+
+	mmc_remove_host(mmc);
+	clk_disable_unprepare(sprd_host->clk_sdio);
+	clk_disable_unprepare(sprd_host->clk_enable);
+
+	mmc_free_host(mmc);
+
+	return 0;
+}
+
+static const struct of_device_id sdhci_sprd_of_match[] = {
+	{ .compatible = "sprd,sdhci-r11", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, sdhci_sprd_of_match);
+
+#ifdef CONFIG_PM
+static int sdhci_sprd_runtime_suspend(struct device *dev)
+{
+	struct sdhci_host *host = dev_get_drvdata(dev);
+	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);
+
+	sdhci_runtime_suspend_host(host);
+
+	clk_disable_unprepare(sprd_host->clk_sdio);
+	clk_disable_unprepare(sprd_host->clk_enable);
+
+	return 0;
+}
+
+static int sdhci_sprd_runtime_resume(struct device *dev)
+{
+	struct sdhci_host *host = dev_get_drvdata(dev);
+	struct sdhci_sprd_host *sprd_host = TO_SPRD_HOST(host);
+	int ret;
+
+	ret = clk_prepare_enable(sprd_host->clk_enable);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(sprd_host->clk_sdio);
+	if (ret) {
+		clk_disable_unprepare(sprd_host->clk_enable);
+		return ret;
+	}
+
+	sdhci_runtime_resume_host(host);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops sdhci_sprd_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+	SET_RUNTIME_PM_OPS(sdhci_sprd_runtime_suspend,
+			   sdhci_sprd_runtime_resume, NULL)
+};
+
+static struct platform_driver sdhci_sprd_driver = {
+	.probe = sdhci_sprd_probe,
+	.remove = sdhci_sprd_remove,
+	.driver = {
+		.name = "sdhci_sprd_r11",
+		.of_match_table = of_match_ptr(sdhci_sprd_of_match),
+		.pm = &sdhci_sprd_pm_ops,
+	},
+};
+module_platform_driver(sdhci_sprd_driver);
+
+MODULE_DESCRIPTION("Spreadtrum sdio host controller r11 driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:sdhci-sprd-r11");
-- 
2.7.4