mmc: mmci: add stm32 sdmmc variant

This patch adds a stm32 sdmmc variant, rev 1.1.
Introduces a new Manufacturer id "0x53, ascii 'S' to define
new stm32 sdmmc family with clean range of amba
revision/configurations bits (corresponding to sdmmc_ver
register with major/minor fields).
Add 2 variants properties:
-dma_lli, to enable link list support.
-stm32_idmabsize_mask, defines the range of SDMMC_IDMABSIZER register
 which specify the number bytes per buffer.

DT properties for sdmmc:
-Indicate signal directions (only one property
 for d0dir, d123dir, cmd_dir)
-Select command and data phase relation.
-Select "clock in" from an external driver.

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 282 insertions, 0 deletions

diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
new file mode 100644
index 000000000000..cfbfc6f1048f
--- /dev/null
+++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
@@ -0,0 +1,282 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) STMicroelectronics 2018 - All Rights Reserved
+ * Author: Ludovic.barre@st.com for STMicroelectronics.
+ */
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/mmc/host.h>
+#include <linux/mmc/card.h>
+#include <linux/reset.h>
+#include <linux/scatterlist.h>
+#include "mmci.h"
+
+#define SDMMC_LLI_BUF_LEN	PAGE_SIZE
+#define SDMMC_IDMA_BURST	BIT(MMCI_STM32_IDMABNDT_SHIFT)
+
+struct sdmmc_lli_desc {
+	u32 idmalar;
+	u32 idmabase;
+	u32 idmasize;
+};
+
+struct sdmmc_priv {
+	dma_addr_t sg_dma;
+	void *sg_cpu;
+};
+
+int sdmmc_idma_validate_data(struct mmci_host *host,
+			     struct mmc_data *data)
+{
+	struct scatterlist *sg;
+	int i;
+
+	/*
+	 * idma has constraints on idmabase & idmasize for each element
+	 * excepted the last element which has no constraint on idmasize
+	 */
+	for_each_sg(data->sg, sg, data->sg_len - 1, i) {
+		if (!IS_ALIGNED(sg_dma_address(data->sg), sizeof(u32)) ||
+		    !IS_ALIGNED(sg_dma_len(data->sg), SDMMC_IDMA_BURST)) {
+			dev_err(mmc_dev(host->mmc),
+				"unaligned scatterlist: ofst:%x length:%d\n",
+				data->sg->offset, data->sg->length);
+			return -EINVAL;
+		}
+	}
+
+	if (!IS_ALIGNED(sg_dma_address(data->sg), sizeof(u32))) {
+		dev_err(mmc_dev(host->mmc),
+			"unaligned last scatterlist: ofst:%x length:%d\n",
+			data->sg->offset, data->sg->length);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int _sdmmc_idma_prep_data(struct mmci_host *host,
+				 struct mmc_data *data)
+{
+	int n_elem;
+
+	n_elem = dma_map_sg(mmc_dev(host->mmc),
+			    data->sg,
+			    data->sg_len,
+			    mmc_get_dma_dir(data));
+
+	if (!n_elem) {
+		dev_err(mmc_dev(host->mmc), "dma_map_sg failed\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int sdmmc_idma_prep_data(struct mmci_host *host,
+				struct mmc_data *data, bool next)
+{
+	/* Check if job is already prepared. */
+	if (!next && data->host_cookie == host->next_cookie)
+		return 0;
+
+	return _sdmmc_idma_prep_data(host, data);
+}
+
+static void sdmmc_idma_unprep_data(struct mmci_host *host,
+				   struct mmc_data *data, int err)
+{
+	dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
+		     mmc_get_dma_dir(data));
+}
+
+static int sdmmc_idma_setup(struct mmci_host *host)
+{
+	struct sdmmc_priv *idma;
+
+	idma = devm_kzalloc(mmc_dev(host->mmc), sizeof(*idma), GFP_KERNEL);
+	if (!idma)
+		return -ENOMEM;
+
+	host->dma_priv = idma;
+
+	if (host->variant->dma_lli) {
+		idma->sg_cpu = dmam_alloc_coherent(mmc_dev(host->mmc),
+						   SDMMC_LLI_BUF_LEN,
+						   &idma->sg_dma, GFP_KERNEL);
+		if (!idma->sg_cpu) {
+			dev_err(mmc_dev(host->mmc),
+				"Failed to alloc IDMA descriptor\n");
+			return -ENOMEM;
+		}
+		host->mmc->max_segs = SDMMC_LLI_BUF_LEN /
+			sizeof(struct sdmmc_lli_desc);
+		host->mmc->max_seg_size = host->variant->stm32_idmabsize_mask;
+	} else {
+		host->mmc->max_segs = 1;
+		host->mmc->max_seg_size = host->mmc->max_req_size;
+	}
+
+	return 0;
+}
+
+static int sdmmc_idma_start(struct mmci_host *host, unsigned int *datactrl)
+
+{
+	struct sdmmc_priv *idma = host->dma_priv;
+	struct sdmmc_lli_desc *desc = (struct sdmmc_lli_desc *)idma->sg_cpu;
+	struct mmc_data *data = host->data;
+	struct scatterlist *sg;
+	int i;
+
+	if (!host->variant->dma_lli || data->sg_len == 1) {
+		writel_relaxed(sg_dma_address(data->sg),
+			       host->base + MMCI_STM32_IDMABASE0R);
+		writel_relaxed(MMCI_STM32_IDMAEN,
+			       host->base + MMCI_STM32_IDMACTRLR);
+		return 0;
+	}
+
+	for_each_sg(data->sg, sg, data->sg_len, i) {
+		desc[i].idmalar = (i + 1) * sizeof(struct sdmmc_lli_desc);
+		desc[i].idmalar |= MMCI_STM32_ULA | MMCI_STM32_ULS
+			| MMCI_STM32_ABR;
+		desc[i].idmabase = sg_dma_address(sg);
+		desc[i].idmasize = sg_dma_len(sg);
+	}
+
+	/* notice the end of link list */
+	desc[data->sg_len - 1].idmalar &= ~MMCI_STM32_ULA;
+
+	dma_wmb();
+	writel_relaxed(idma->sg_dma, host->base + MMCI_STM32_IDMABAR);
+	writel_relaxed(desc[0].idmalar, host->base + MMCI_STM32_IDMALAR);
+	writel_relaxed(desc[0].idmabase, host->base + MMCI_STM32_IDMABASE0R);
+	writel_relaxed(desc[0].idmasize, host->base + MMCI_STM32_IDMABSIZER);
+	writel_relaxed(MMCI_STM32_IDMAEN | MMCI_STM32_IDMALLIEN,
+		       host->base + MMCI_STM32_IDMACTRLR);
+
+	return 0;
+}
+
+static void sdmmc_idma_finalize(struct mmci_host *host, struct mmc_data *data)
+{
+	writel_relaxed(0, host->base + MMCI_STM32_IDMACTRLR);
+}
+
+static void mmci_sdmmc_set_clkreg(struct mmci_host *host, unsigned int desired)
+{
+	unsigned int clk = 0, ddr = 0;
+
+	if (host->mmc->ios.timing == MMC_TIMING_MMC_DDR52 ||
+	    host->mmc->ios.timing == MMC_TIMING_UHS_DDR50)
+		ddr = MCI_STM32_CLK_DDR;
+
+	/*
+	 * cclk = mclk / (2 * clkdiv)
+	 * clkdiv 0 => bypass
+	 * in ddr mode bypass is not possible
+	 */
+	if (desired) {
+		if (desired >= host->mclk && !ddr) {
+			host->cclk = host->mclk;
+		} else {
+			clk = DIV_ROUND_UP(host->mclk, 2 * desired);
+			if (clk > MCI_STM32_CLK_CLKDIV_MSK)
+				clk = MCI_STM32_CLK_CLKDIV_MSK;
+			host->cclk = host->mclk / (2 * clk);
+		}
+	} else {
+		/*
+		 * while power-on phase the clock can't be define to 0,
+		 * Only power-off and power-cyc deactivate the clock.
+		 * if desired clock is 0, set max divider
+		 */
+		clk = MCI_STM32_CLK_CLKDIV_MSK;
+		host->cclk = host->mclk / (2 * clk);
+	}
+
+	/* Set actual clock for debug */
+	if (host->mmc->ios.power_mode == MMC_POWER_ON)
+		host->mmc->actual_clock = host->cclk;
+	else
+		host->mmc->actual_clock = 0;
+
+	if (host->mmc->ios.bus_width == MMC_BUS_WIDTH_4)
+		clk |= MCI_STM32_CLK_WIDEBUS_4;
+	if (host->mmc->ios.bus_width == MMC_BUS_WIDTH_8)
+		clk |= MCI_STM32_CLK_WIDEBUS_8;
+
+	clk |= MCI_STM32_CLK_HWFCEN;
+	clk |= host->clk_reg_add;
+	clk |= ddr;
+
+	/*
+	 * SDMMC_FBCK is selected when an external Delay Block is needed
+	 * with SDR104.
+	 */
+	if (host->mmc->ios.timing >= MMC_TIMING_UHS_SDR50) {
+		clk |= MCI_STM32_CLK_BUSSPEED;
+		if (host->mmc->ios.timing == MMC_TIMING_UHS_SDR104) {
+			clk &= ~MCI_STM32_CLK_SEL_MSK;
+			clk |= MCI_STM32_CLK_SELFBCK;
+		}
+	}
+
+	mmci_write_clkreg(host, clk);
+}
+
+static void mmci_sdmmc_set_pwrreg(struct mmci_host *host, unsigned int pwr)
+{
+	struct mmc_ios ios = host->mmc->ios;
+
+	pwr = host->pwr_reg_add;
+
+	if (ios.power_mode == MMC_POWER_OFF) {
+		/* Only a reset could power-off sdmmc */
+		reset_control_assert(host->rst);
+		udelay(2);
+		reset_control_deassert(host->rst);
+
+		/*
+		 * Set the SDMMC in Power-cycle state.
+		 * This will make that the SDMMC_D[7:0], SDMMC_CMD and SDMMC_CK
+		 * are driven low, to prevent the Card from being supplied
+		 * through the signal lines.
+		 */
+		mmci_write_pwrreg(host, MCI_STM32_PWR_CYC | pwr);
+	} else if (ios.power_mode == MMC_POWER_ON) {
+		/*
+		 * After power-off (reset): the irq mask defined in probe
+		 * functionis lost
+		 * ault irq mask (probe) must be activated
+		 */
+		writel(MCI_IRQENABLE | host->variant->start_err,
+		       host->base + MMCIMASK0);
+
+		/*
+		 * After a power-cycle state, we must set the SDMMC in
+		 * Power-off. The SDMMC_D[7:0], SDMMC_CMD and SDMMC_CK are
+		 * driven high. Then we can set the SDMMC to Power-on state
+		 */
+		mmci_write_pwrreg(host, MCI_PWR_OFF | pwr);
+		mdelay(1);
+		mmci_write_pwrreg(host, MCI_PWR_ON | pwr);
+	}
+}
+
+static struct mmci_host_ops sdmmc_variant_ops = {
+	.validate_data = sdmmc_idma_validate_data,
+	.prep_data = sdmmc_idma_prep_data,
+	.unprep_data = sdmmc_idma_unprep_data,
+	.dma_setup = sdmmc_idma_setup,
+	.dma_start = sdmmc_idma_start,
+	.dma_finalize = sdmmc_idma_finalize,
+	.set_clkreg = mmci_sdmmc_set_clkreg,
+	.set_pwrreg = mmci_sdmmc_set_pwrreg,
+};
+
+void sdmmc_variant_init(struct mmci_host *host)
+{
+	host->ops = &sdmmc_variant_ops;
+}