[PATCH v4 3/3] mmc: host: add Coldfire esdhc support

[Angelo Dureghello <angelo.dureghello@timesys.com>]

This driver has been developed as a separate module starting
from the similar sdhci-esdhc-imx.c.

Reasons for a separate sdchi-esdhc-mcf driver:

- m68K architecture does not support devicetrees, so modifying
sdhci-of-esdhc.c that is devicetree-related adding platform data
seems not appropriate,
- clock-related part, has to be implemented specifically for
mcf5441x family (see esdhc_mcf_pltfm_set_clock()),
- this is a big endian cpu accessing a big endian controller,
but about sdma, this controller does not support hw swap, which
needs to be handled with specific code,
- some other minor differences but mainly to avoid risks on
tweaking inside largely used imx driver. Adding just a small
size ColdFire-specific driver, with benefits in a further less
risky maintenance.

Signed-off-by: Angelo Dureghello <angelo.dureghello@timesys.com>
---
Changes for v3:
- fix write support
Changes for v4:
none
---
 drivers/mmc/host/Kconfig           |  13 +
 drivers/mmc/host/Makefile          |   1 +
 drivers/mmc/host/sdhci-esdhc-mcf.c | 503 +++++++++++++++++++++++++++++
 3 files changed, 517 insertions(+)
 create mode 100644 drivers/mmc/host/sdhci-esdhc-mcf.c

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 462b5352fea7..da793fc95203 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -235,6 +235,19 @@ config MMC_SDHCI_CNS3XXX
 
 	  If unsure, say N.
 
+config MMC_SDHCI_ESDHC_MCF
+	tristate "SDHCI support for the Freescale eSDHC ColdFire controller"
+	depends on M5441x
+	depends on MMC_SDHCI_PLTFM
+	select MMC_SDHCI_IO_ACCESSORS
+	help
+	  This selects the Freescale eSDHC controller support for
+	  ColdFire mcf5441x devices.
+
+	  If you have a controller with this interface, say Y or M here.
+
+	  If unsure, say N.
+
 config MMC_SDHCI_ESDHC_IMX
 	tristate "SDHCI support for the Freescale eSDHC/uSDHC i.MX controller"
 	depends on ARCH_MXC
diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index b929ef941208..af2cdaadc4d3 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -82,6 +82,7 @@ obj-$(CONFIG_MMC_REALTEK_USB)	+= rtsx_usb_sdmmc.o
 obj-$(CONFIG_MMC_SDHCI_PLTFM)		+= sdhci-pltfm.o
 obj-$(CONFIG_MMC_SDHCI_CADENCE)		+= sdhci-cadence.o
 obj-$(CONFIG_MMC_SDHCI_CNS3XXX)		+= sdhci-cns3xxx.o
+obj-$(CONFIG_MMC_SDHCI_ESDHC_MCF)       += sdhci-esdhc-mcf.o
 obj-$(CONFIG_MMC_SDHCI_ESDHC_IMX)	+= sdhci-esdhc-imx.o
 obj-$(CONFIG_MMC_SDHCI_DOVE)		+= sdhci-dove.o
 obj-$(CONFIG_MMC_SDHCI_TEGRA)		+= sdhci-tegra.o
diff --git a/drivers/mmc/host/sdhci-esdhc-mcf.c b/drivers/mmc/host/sdhci-esdhc-mcf.c
new file mode 100644
index 000000000000..658b687c7a51
--- /dev/null
+++ b/drivers/mmc/host/sdhci-esdhc-mcf.c
@@ -0,0 +1,503 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Freescale eSDHC ColdFire family controller driver, platform bus.
+ *
+ * Copyright (c) 2020 Timesys Corporation
+ *   Author: Angelo Dureghello <angelo.dureghello@timesys.it>
+ */
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/platform_data/mmc-esdhc-mcf.h>
+#include <linux/mmc/mmc.h>
+#include "sdhci-pltfm.h"
+#include "sdhci-esdhc.h"
+
+#define	ESDHC_PROCTL_D3CD		0x08
+#define ESDHC_SYS_CTRL_DTOCV_MASK	0x0f
+#define ESDHC_DEFAULT_HOST_CONTROL	0x28
+
+/*
+ * Freescale eSDHC has DMA ERR flag at bit 28, not as std spec says, bit 25.
+ */
+#define ESDHC_INT_VENDOR_SPEC_DMA_ERR	(1 << 28)
+
+struct pltfm_mcf_data {
+	struct clk *clk_ipg;
+	struct clk *clk_ahb;
+	struct clk *clk_per;
+	int aside;
+	int current_bus_width;
+};
+
+static inline void esdhc_mcf_buffer_swap32(u32 *buf, int len)
+{
+	int i;
+	u32 temp;
+
+	len = (len + 3) >> 2;
+
+	for (i = 0; i < len;  i++) {
+		temp = swab32(*buf);
+		*buf++ = temp;
+	}
+}
+
+static inline void esdhc_clrset_be(struct sdhci_host *host,
+				   u32 mask, u32 val, int reg)
+{
+	void __iomem *base = host->ioaddr + (reg & ~3);
+	u8 shift = (reg & 3) << 3;
+
+	mask <<= shift;
+	val <<= shift;
+
+	if (reg == SDHCI_HOST_CONTROL)
+		val |= ESDHC_PROCTL_D3CD;
+
+	writel((readl(base) & ~mask) | val, base);
+}
+
+/*
+ * Note: mcf is big-endian, single bytes need to be accessed at big endian
+ * offsets.
+ */
+static void esdhc_mcf_writeb_be(struct sdhci_host *host, u8 val, int reg)
+{
+	void __iomem *base = host->ioaddr + (reg & ~3);
+	u8 shift = (reg & 3) << 3;
+	u32 mask = ~(0xff << shift);
+
+	if (reg == SDHCI_HOST_CONTROL) {
+		u32 host_ctrl = ESDHC_DEFAULT_HOST_CONTROL;
+		u8 dma_bits = (val & SDHCI_CTRL_DMA_MASK) >> 3;
+		u8 tmp = readb(host->ioaddr + SDHCI_HOST_CONTROL + 1);
+
+		tmp &= ~0x03;
+		tmp |= dma_bits;
+
+		/*
+		 * Recomposition needed, restore always endianness and
+		 * keep D3CD and AI, just setting bus width.
+		 */
+		host_ctrl |= val;
+		host_ctrl |= (dma_bits << 8);
+		writel(host_ctrl, host->ioaddr + SDHCI_HOST_CONTROL);
+
+		return;
+	}
+
+	writel((readl(base) & mask) | (val << shift), base);
+}
+
+static void esdhc_mcf_writew_be(struct sdhci_host *host, u16 val, int reg)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct pltfm_mcf_data *mcf_data = sdhci_pltfm_priv(pltfm_host);
+	void __iomem *base = host->ioaddr + (reg & ~3);
+	u8 shift = (reg & 3) << 3;
+	u32 mask = ~(0xffff << shift);
+
+	switch (reg) {
+	case SDHCI_TRANSFER_MODE:
+		mcf_data->aside = val;
+		return;
+	case SDHCI_COMMAND:
+		if (host->cmd->opcode == MMC_STOP_TRANSMISSION)
+			val |= SDHCI_CMD_ABORTCMD;
+
+		/*
+		 * As for the fsl driver,
+		 * we have to set the mode in a single write here.
+		 */
+		writel(val << 16 | mcf_data->aside,
+			       host->ioaddr + SDHCI_TRANSFER_MODE);
+		return;
+	}
+
+	writel((readl(base) & mask) | (val << shift), base);
+}
+
+static void esdhc_mcf_writel_be(struct sdhci_host *host, u32 val, int reg)
+{
+	writel(val, host->ioaddr + reg);
+}
+
+static u8 esdhc_mcf_readb_be(struct sdhci_host *host, int reg)
+{
+	if (reg == SDHCI_HOST_CONTROL) {
+		u8 __iomem *base = host->ioaddr + (reg & ~3);
+		u16 val = readw(base + 2);
+		u8 dma_bits = (val >> 5) & SDHCI_CTRL_DMA_MASK;
+		u8 host_ctrl = val & 0xff;
+
+		host_ctrl &= ~SDHCI_CTRL_DMA_MASK;
+		host_ctrl |= dma_bits;
+
+		return host_ctrl;
+	}
+
+	return readb(host->ioaddr + (reg ^ 0x3));
+}
+
+static u16 esdhc_mcf_readw_be(struct sdhci_host *host, int reg)
+{
+	/*
+	 * For SDHCI_HOST_VERSION, sdhci specs defines 0xFE,
+	 * a wrong offset for us, we are at 0xFC.
+	 */
+	if (reg == SDHCI_HOST_VERSION)
+		reg -= 2;
+
+	return readw(host->ioaddr + (reg ^ 0x2));
+}
+
+static u32 esdhc_mcf_readl_be(struct sdhci_host *host, int reg)
+{
+	u32 val;
+
+	val = readl(host->ioaddr + reg);
+
+	/*
+	 * RM (25.3.9) sd pin clock must never exceed 25Mhz.
+	 * So forcing legacy mode at 25Mhz.
+	 */
+	if (unlikely(reg == SDHCI_CAPABILITIES))
+		val &= ~SDHCI_CAN_DO_HISPD;
+
+	if (unlikely(reg == SDHCI_INT_STATUS)) {
+		if (val & ESDHC_INT_VENDOR_SPEC_DMA_ERR) {
+			val &= ~ESDHC_INT_VENDOR_SPEC_DMA_ERR;
+			val |= SDHCI_INT_ADMA_ERROR;
+		}
+	}
+
+	return val;
+}
+
+static unsigned int esdhc_mcf_get_max_timeout_count(struct sdhci_host *host)
+{
+	return 1 << 27;
+}
+
+static void esdhc_mcf_set_timeout(struct sdhci_host *host,
+				  struct mmc_command *cmd)
+{
+	/* Use maximum timeout counter */
+	esdhc_clrset_be(host, ESDHC_SYS_CTRL_DTOCV_MASK, 0xE,
+				SDHCI_TIMEOUT_CONTROL);
+}
+
+static void esdhc_mcf_reset(struct sdhci_host *host, u8 mask)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct pltfm_mcf_data *mcf_data = sdhci_pltfm_priv(pltfm_host);
+
+	sdhci_reset(host, mask);
+
+	esdhc_clrset_be(host, ESDHC_CTRL_BUSWIDTH_MASK,
+			mcf_data->current_bus_width, SDHCI_HOST_CONTROL);
+
+	sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
+	sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
+}
+
+static unsigned int esdhc_mcf_pltfm_get_max_clock(struct sdhci_host *host)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+
+	return pltfm_host->clock;
+}
+
+static unsigned int esdhc_mcf_pltfm_get_min_clock(struct sdhci_host *host)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+
+	return pltfm_host->clock / 256 / 16;
+}
+
+static void esdhc_mcf_pltfm_set_clock(struct sdhci_host *host,
+					 unsigned int clock)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	unsigned long *pll_dr = (unsigned long *)MCF_PLL_DR;
+	u32 fvco, fsys, fesdhc, temp;
+	const int sdclkfs[] = {2, 4, 8, 16, 32, 64, 128, 256};
+	int delta, old_delta = clock;
+	int i, q, ri, rq;
+
+	if (clock == 0) {
+		host->mmc->actual_clock = 0;
+		return;
+	}
+
+	/*
+	 * ColdFire eSDHC clock.s
+	 *
+	 * pll -+-> / outdiv1 --> fsys
+	 *      +-> / outdiv3 --> eSDHC clock ---> / SDCCLKFS / DVS
+	 *
+	 * mcf5441x datasheet says:
+	 * (8.1.2) eSDHC should be 40 MHz max
+	 * (25.3.9) eSDHC input is, as example, 96 Mhz ...
+	 * (25.3.9) sd pin clock must never exceed 25Mhz
+	 *
+	 * fvco = fsys * outdvi1 + 1
+	 * fshdc = fvco / outdiv3 + 1
+	 */
+	temp = readl(pll_dr);
+	fsys = pltfm_host->clock;
+	fvco = fsys * ((temp & 0x1f) + 1);
+	fesdhc = fvco / (((temp >> 10) & 0x1f) + 1);
+
+	for (i = 0; i < 8; ++i) {
+		int result = fesdhc / sdclkfs[i];
+
+		for (q = 1; q < 17; ++q) {
+			int finale = result / q;
+
+			delta = abs(clock - finale);
+
+			if (delta < old_delta) {
+				old_delta = delta;
+				ri = i;
+				rq = q;
+			}
+		}
+	}
+
+	/*
+	 * Apply divisors and re-enable all the clocks
+	 */
+	temp = ((sdclkfs[ri] >> 1) << 8) | ((rq - 1) << 4) |
+		(ESDHC_CLOCK_IPGEN | ESDHC_CLOCK_HCKEN | ESDHC_CLOCK_PEREN);
+	esdhc_clrset_be(host, 0x0000fff7, temp, SDHCI_CLOCK_CONTROL);
+
+	host->mmc->actual_clock = clock;
+
+	mdelay(1);
+}
+
+static void esdhc_mcf_pltfm_set_bus_width(struct sdhci_host *host, int width)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct pltfm_mcf_data *mcf_data = sdhci_pltfm_priv(pltfm_host);
+
+	switch (width) {
+	case MMC_BUS_WIDTH_4:
+		mcf_data->current_bus_width = ESDHC_CTRL_4BITBUS;
+		break;
+	default:
+		mcf_data->current_bus_width = 0;
+		break;
+	}
+
+	esdhc_clrset_be(host, ESDHC_CTRL_BUSWIDTH_MASK,
+			mcf_data->current_bus_width, SDHCI_HOST_CONTROL);
+}
+
+static void esdhc_mcf_request_done(struct sdhci_host *host,
+				   struct mmc_request *mrq)
+{
+	struct scatterlist *sg;
+	u32 *buffer;
+	int i;
+
+	if (!mrq->data || !mrq->data->bytes_xfered)
+		goto exit_done;
+
+	if (mmc_get_dma_dir(mrq->data) != DMA_FROM_DEVICE)
+		goto exit_done;
+
+	/*
+	 * On mcf5441x there is no hw sdma option/flag to select the dma
+	 * transfer endiannes. A swap after the transfer is needed.
+	 */
+	for_each_sg(mrq->data->sg, sg, mrq->data->sg_len, i) {
+		buffer = (u32 *)sg_virt(sg);
+		esdhc_mcf_buffer_swap32(buffer, sg->length);
+	}
+
+exit_done:
+	mmc_request_done(host->mmc, mrq);
+}
+
+static void esdhc_mcf_pre_dma_transfer(struct sdhci_host *host,
+	struct mmc_data *data)
+{
+	esdhc_mcf_buffer_swap32((u32 *)host->bounce_buffer,
+				data->blksz * data->blocks);
+}
+
+static struct sdhci_ops sdhci_esdhc_ops = {
+	.reset = esdhc_mcf_reset,
+	.set_clock = esdhc_mcf_pltfm_set_clock,
+	.get_max_clock = esdhc_mcf_pltfm_get_max_clock,
+	.get_min_clock = esdhc_mcf_pltfm_get_min_clock,
+	.set_bus_width = esdhc_mcf_pltfm_set_bus_width,
+	.get_max_timeout_count = esdhc_mcf_get_max_timeout_count,
+	.set_timeout = esdhc_mcf_set_timeout,
+	.write_b = esdhc_mcf_writeb_be,
+	.write_w = esdhc_mcf_writew_be,
+	.write_l = esdhc_mcf_writel_be,
+	.read_b = esdhc_mcf_readb_be,
+	.read_w = esdhc_mcf_readw_be,
+	.read_l = esdhc_mcf_readl_be,
+	.pre_dma_transfer = esdhc_mcf_pre_dma_transfer,
+	.request_done = esdhc_mcf_request_done,
+};
+
+static const struct sdhci_pltfm_data sdhci_esdhc_mcf_pdata = {
+	.ops = &sdhci_esdhc_ops,
+	.quirks = ESDHC_DEFAULT_QUIRKS | SDHCI_QUIRK_FORCE_DMA,
+		 /*
+		  * Mandatory quirk,
+		  * controller does not support cmd23,
+		  * without, on > 8G cards cmd23 is used, and
+		  * driver times out.
+		  */
+		  SDHCI_QUIRK2_HOST_NO_CMD23,
+};
+
+static int esdhc_mcf_plat_init(struct sdhci_host *host,
+				     struct pltfm_mcf_data *mcf_data)
+{
+	struct mcf_esdhc_platform_data *plat_data;
+
+	if (!host->mmc->parent->platform_data) {
+		dev_err(mmc_dev(host->mmc), "no platform data!\n");
+		return -EINVAL;
+	}
+
+	plat_data = ((struct mcf_esdhc_platform_data *)
+			host->mmc->parent->platform_data);
+
+	/* Card_detect */
+	switch (plat_data->cd_type) {
+	default:
+	case ESDHC_CD_CONTROLLER:
+		/* We have a working card_detect back */
+		host->quirks &= ~SDHCI_QUIRK_BROKEN_CARD_DETECTION;
+		break;
+	case ESDHC_CD_PERMANENT:
+		host->mmc->caps |= MMC_CAP_NONREMOVABLE;
+		break;
+	case ESDHC_CD_NONE:
+		break;
+	}
+
+	switch (plat_data->max_bus_width) {
+	case 4:
+		host->mmc->caps |= MMC_CAP_4_BIT_DATA;
+		break;
+	case 1:
+	default:
+		host->quirks |= SDHCI_QUIRK_FORCE_1_BIT_DATA;
+		break;
+	}
+
+	return 0;
+}
+
+static int sdhci_esdhc_mcf_probe(struct platform_device *pdev)
+{
+	struct sdhci_host *host;
+	struct sdhci_pltfm_host *pltfm_host;
+	struct pltfm_mcf_data *mcf_data;
+	int err;
+
+	host = sdhci_pltfm_init(pdev, &sdhci_esdhc_mcf_pdata,
+				sizeof(*mcf_data));
+
+	if (IS_ERR(host))
+		return PTR_ERR(host);
+
+	pltfm_host = sdhci_priv(host);
+	mcf_data = sdhci_pltfm_priv(pltfm_host);
+
+	host->sdma_boundary = 0;
+
+	host->flags |= SDHCI_AUTO_CMD12;
+
+	mcf_data->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
+	if (IS_ERR(mcf_data->clk_ipg)) {
+		err = PTR_ERR(mcf_data->clk_ipg);
+		goto err_exit;
+	}
+
+	mcf_data->clk_ahb = devm_clk_get(&pdev->dev, "ahb");
+	if (IS_ERR(mcf_data->clk_ahb)) {
+		err = PTR_ERR(mcf_data->clk_ahb);
+		goto err_exit;
+	}
+
+	mcf_data->clk_per = devm_clk_get(&pdev->dev, "per");
+	if (IS_ERR(mcf_data->clk_per)) {
+		err = PTR_ERR(mcf_data->clk_per);
+		goto err_exit;
+	}
+
+	pltfm_host->clk = mcf_data->clk_per;
+	pltfm_host->clock = clk_get_rate(pltfm_host->clk);
+	err = clk_prepare_enable(mcf_data->clk_per);
+	if (err)
+		goto err_exit;
+
+	err = clk_prepare_enable(mcf_data->clk_ipg);
+	if (err) {
+		clk_disable_unprepare(mcf_data->clk_per);
+		goto err_exit;
+	}
+	err = clk_prepare_enable(mcf_data->clk_ahb);
+	if (err) {
+		clk_disable_unprepare(mcf_data->clk_per);
+		clk_disable_unprepare(mcf_data->clk_ipg);
+		goto err_exit;
+	}
+
+	err = esdhc_mcf_plat_init(host, mcf_data);
+	if (err)
+		goto err_exit;
+
+	err = sdhci_add_host(host);
+	if (err)
+		goto err_exit;
+
+	return 0;
+
+err_exit:
+	sdhci_pltfm_free(pdev);
+
+	return err;
+}
+
+static int sdhci_esdhc_mcf_remove(struct platform_device *pdev)
+{
+	struct sdhci_host *host = platform_get_drvdata(pdev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct pltfm_mcf_data *mcf_data = sdhci_pltfm_priv(pltfm_host);
+
+	sdhci_remove_host(host, 0);
+
+	clk_disable_unprepare(mcf_data->clk_ipg);
+	clk_disable_unprepare(mcf_data->clk_ahb);
+	clk_disable_unprepare(mcf_data->clk_per);
+
+	sdhci_pltfm_free(pdev);
+
+	return 0;
+}
+
+static struct platform_driver sdhci_esdhc_mcf_driver = {
+	.driver	= {
+		.name = "sdhci-esdhc-mcf",
+	},
+	.probe = sdhci_esdhc_mcf_probe,
+	.remove = sdhci_esdhc_mcf_remove,
+};
+
+module_platform_driver(sdhci_esdhc_mcf_driver);
+
+MODULE_DESCRIPTION("SDHCI driver for Freescale ColdFire eSDHC");
+MODULE_AUTHOR("Angelo Dureghello <angelo.dureghello@timesys.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.26.2