mmc: loongson2: Add Loongson-2K2000 SD/SDIO/eMMC controller driver

This patch describes the two MMC controllers of the Loongson-2K2000 SoC,
one providing an eMMC interface and the other exporting an SD/SDIO
interface.

Compared to the Loongson-2K1000's MMC controllers, their internals are
similar, except that we use an internally exclusive DMA engine instead of
an externally shared APBDMA engine.

Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Link: https://lore.kernel.org/r/1df46b976abd36003bd553ad8a039e5c97369df0.1750765495.git.zhoubinbin@loongson.cn
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Author: AaronDot

drivers/mmc/host/loongson2-mmc.c

@@ -44,6 +44,18 @@
 #define LOONGSON2_MMC_REG_DATA		0x40 /* Data Register */
 #define LOONGSON2_MMC_REG_IEN		0x64 /* Interrupt Enable Register */
 
+/* EMMC DLL Mode Registers */
+#define LOONGSON2_MMC_REG_DLLVAL	0xf0 /* DLL Master Lock-value Register */
+#define LOONGSON2_MMC_REG_DLLCTL	0xf4 /* DLL Control Register */
+#define LOONGSON2_MMC_REG_DELAY		0xf8 /* DLL Delayed Parameter Register */
+#define LOONGSON2_MMC_REG_SEL		0xfc /* Bus Mode Selection Register */
+
+/* Exclusive DMA R/W Registers */
+#define LOONGSON2_MMC_REG_WDMA_LO	0x400
+#define LOONGSON2_MMC_REG_WDMA_HI	0x404
+#define LOONGSON2_MMC_REG_RDMA_LO	0x800
+#define LOONGSON2_MMC_REG_RDMA_HI	0x804
+
 /* Bitfields of control register */
 #define LOONGSON2_MMC_CTL_ENCLK		BIT(0)
 #define LOONGSON2_MMC_CTL_EXTCLK	BIT(1)
@@ -109,6 +121,9 @@
 #define LOONGSON2_MMC_DSTS_RESUME	BIT(15)
 #define LOONGSON2_MMC_DSTS_SUSPEND	BIT(16)
 
+/* Bitfields of FIFO Status Register */
+#define LOONGSON2_MMC_FSTS_TXFULL	BIT(11)
+
 /* Bitfields of interrupt register */
 #define LOONGSON2_MMC_INT_DFIN		BIT(0)
 #define LOONGSON2_MMC_INT_DTIMEOUT	BIT(1)
@@ -136,6 +151,44 @@
 #define LOONGSON2_MMC_IEN_ALL		GENMASK(9, 0)
 #define LOONGSON2_MMC_INT_CLEAR		GENMASK(9, 0)
 
+/* Bitfields of DLL master lock-value register */
+#define LOONGSON2_MMC_DLLVAL_DONE	BIT(8)
+
+/* Bitfields of DLL control register */
+#define LOONGSON2_MMC_DLLCTL_TIME	GENMASK(7, 0)
+#define LOONGSON2_MMC_DLLCTL_INCRE	GENMASK(15, 8)
+#define LOONGSON2_MMC_DLLCTL_START	GENMASK(23, 16)
+#define LOONGSON2_MMC_DLLCTL_CLK_MODE	BIT(24)
+#define LOONGSON2_MMC_DLLCTL_START_BIT	BIT(25)
+#define LOONGSON2_MMC_DLLCTL_TIME_BPASS	GENMASK(29, 26)
+
+#define LOONGSON2_MMC_DELAY_PAD		GENMASK(7, 0)
+#define LOONGSON2_MMC_DELAY_RD		GENMASK(15, 8)
+
+#define LOONGSON2_MMC_SEL_DATA		BIT(0)	/* 0: SDR, 1: DDR */
+#define LOONGSON2_MMC_SEL_BUS		BIT(0)	/* 0: EMMC, 1: SDIO */
+
+/* Internal dma controller registers */
+
+/* Bitfields of Global Configuration Register */
+#define LOONGSON2_MMC_DMA_64BIT_EN	BIT(0) /* 1: 64 bit support */
+#define LOONGSON2_MMC_DMA_UNCOHERENT_EN	BIT(1) /* 0: cache, 1: uncache */
+#define LOONGSON2_MMC_DMA_ASK_VALID	BIT(2)
+#define LOONGSON2_MMC_DMA_START		BIT(3) /* DMA start operation */
+#define LOONGSON2_MMC_DMA_STOP		BIT(4) /* DMA stop operation */
+#define LOONGSON2_MMC_DMA_CONFIG_MASK	GENMASK_ULL(4, 0) /* DMA controller config bits mask */
+
+/* Bitfields of ndesc_addr field of HW descriptor */
+#define LOONGSON2_MMC_DMA_DESC_EN	BIT(0) /*1: The next descriptor is valid */
+#define LOONGSON2_MMC_DMA_DESC_ADDR_LOW	GENMASK(31, 1)
+
+/* Bitfields of cmd field of HW descriptor */
+#define LOONGSON2_MMC_DMA_INT		BIT(1)	/* Enable DMA interrupts */
+#define LOONGSON2_MMC_DMA_DATA_DIR	BIT(12) /* 1: write to device, 0: read from device */
+
+#define LOONGSON2_MMC_DLLVAL_TIMEOUT_US		4000
+#define LOONGSON2_MMC_TXFULL_TIMEOUT_US		500
+
 /* Loongson-2K1000 SDIO2 DMA routing register */
 #define LS2K1000_SDIO_DMA_MASK		GENMASK(17, 15)
 #define LS2K1000_DMA0_CONF		0x0
@@ -159,13 +212,29 @@ enum loongson2_mmc_state {
 	STATE_XFERFINISH_RSPFIN,
 };
 
+struct loongson2_dma_desc {
+	u32 ndesc_addr;
+	u32 mem_addr;
+	u32 apb_addr;
+	u32 len;
+	u32 step_len;
+	u32 step_times;
+	u32 cmd;
+	u32 stats;
+	u32 high_ndesc_addr;
+	u32 high_mem_addr;
+	u32 reserved[2];
+} __packed;
+
 struct loongson2_mmc_host {
 	struct device *dev;
 	struct mmc_request *mrq;
 	struct regmap *regmap;
 	struct resource *res;
 	struct clk *clk;
 	u32 current_clk;
+	void *sg_cpu;
+	dma_addr_t sg_dma;
 	int dma_complete;
 	struct dma_chan *chan;
 	int cmd_is_stop;
@@ -178,6 +247,7 @@ struct loongson2_mmc_host {
 struct loongson2_mmc_pdata {
 	const struct regmap_config *regmap_config;
 	void (*reorder_cmd_data)(struct loongson2_mmc_host *host, struct mmc_command *cmd);
+	void (*fix_data_timeout)(struct loongson2_mmc_host *host, struct mmc_command *cmd);
 	int (*setting_dma)(struct loongson2_mmc_host *host, struct platform_device *pdev);
 	int (*prepare_dma)(struct loongson2_mmc_host *host, struct mmc_data *data);
 	void (*release_dma)(struct loongson2_mmc_host *host, struct device *dev);
@@ -268,6 +338,9 @@ static void loongson2_mmc_send_request(struct mmc_host *mmc)
 		return;
 	}
 
+	if (host->pdata->fix_data_timeout)
+		host->pdata->fix_data_timeout(host, cmd);
+
 	loongson2_mmc_send_command(host, cmd);
 
 	/* Fix deselect card */
@@ -410,6 +483,37 @@ static irqreturn_t loongson2_mmc_irq(int irq, void *devid)
 	return IRQ_WAKE_THREAD;
 }
 
+static void loongson2_mmc_dll_mode_init(struct loongson2_mmc_host *host)
+{
+	u32 val, pad_delay, delay, ret;
+
+	regmap_update_bits(host->regmap, LOONGSON2_MMC_REG_SEL,
+			   LOONGSON2_MMC_SEL_DATA, LOONGSON2_MMC_SEL_DATA);
+
+	val = FIELD_PREP(LOONGSON2_MMC_DLLCTL_TIME, 0xc8)
+	    | FIELD_PREP(LOONGSON2_MMC_DLLCTL_INCRE, 0x1)
+	    | FIELD_PREP(LOONGSON2_MMC_DLLCTL_START, 0x1)
+	    | FIELD_PREP(LOONGSON2_MMC_DLLCTL_CLK_MODE, 0x1)
+	    | FIELD_PREP(LOONGSON2_MMC_DLLCTL_START_BIT, 0x1)
+	    | FIELD_PREP(LOONGSON2_MMC_DLLCTL_TIME_BPASS, 0xf);
+
+	regmap_write(host->regmap, LOONGSON2_MMC_REG_DLLCTL, val);
+
+	ret = regmap_read_poll_timeout(host->regmap, LOONGSON2_MMC_REG_DLLVAL, val,
+				       (val & LOONGSON2_MMC_DLLVAL_DONE), 0,
+				       LOONGSON2_MMC_DLLVAL_TIMEOUT_US);
+	if (ret < 0)
+		return;
+
+	regmap_read(host->regmap, LOONGSON2_MMC_REG_DLLVAL, &val);
+	pad_delay = FIELD_GET(GENMASK(7, 1), val);
+
+	delay = FIELD_PREP(LOONGSON2_MMC_DELAY_PAD, pad_delay)
+	      | FIELD_PREP(LOONGSON2_MMC_DELAY_RD, pad_delay + 1);
+
+	regmap_write(host->regmap, LOONGSON2_MMC_REG_DELAY, delay);
+}
+
 static void loongson2_mmc_set_clk(struct loongson2_mmc_host *host, struct mmc_ios *ios)
 {
 	u32 pre;
@@ -422,6 +526,10 @@ static void loongson2_mmc_set_clk(struct loongson2_mmc_host *host, struct mmc_io
 
 	regmap_update_bits(host->regmap, LOONGSON2_MMC_REG_CTL,
 			   LOONGSON2_MMC_CTL_ENCLK, LOONGSON2_MMC_CTL_ENCLK);
+
+	/* EMMC DLL mode setting */
+	if (ios->timing == MMC_TIMING_UHS_DDR50 || ios->timing == MMC_TIMING_MMC_DDR52)
+		loongson2_mmc_dll_mode_init(host);
 }
 
 static void loongson2_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
@@ -634,6 +742,128 @@ static struct loongson2_mmc_pdata ls2k1000_mmc_pdata = {
 	.release_dma		= loongson2_mmc_release_external_dma,
 };
 
+static const struct regmap_config ls2k2000_mmc_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = LOONGSON2_MMC_REG_RDMA_HI,
+};
+
+static void ls2k2000_mmc_reorder_cmd_data(struct loongson2_mmc_host *host,
+					  struct mmc_command *cmd)
+{
+	struct scatterlist *sg;
+	u32 *data;
+	int i, j;
+
+	if (cmd->opcode != SD_SWITCH || mmc_cmd_type(cmd) != MMC_CMD_ADTC)
+		return;
+
+	for_each_sg(cmd->data->sg, sg, cmd->data->sg_len, i) {
+		data = sg_virt(&sg[i]);
+		for (j = 0; j < (sg_dma_len(&sg[i]) / 4); j++)
+			data[j] = bitrev8x4(data[j]);
+	}
+}
+
+/*
+ * This is a controller hardware defect. Single/multiple block write commands
+ * must be sent after the TX FULL flag is set, otherwise a data timeout interrupt
+ * will occur.
+ */
+static void ls2k2000_mmc_fix_data_timeout(struct loongson2_mmc_host *host,
+					  struct mmc_command *cmd)
+{
+	int val;
+
+	if (cmd->opcode != MMC_WRITE_BLOCK && cmd->opcode != MMC_WRITE_MULTIPLE_BLOCK)
+		return;
+
+	regmap_read_poll_timeout(host->regmap, LOONGSON2_MMC_REG_FSTS, val,
+				 (val & LOONGSON2_MMC_FSTS_TXFULL), 0,
+				 LOONGSON2_MMC_TXFULL_TIMEOUT_US);
+}
+
+static int loongson2_mmc_prepare_internal_dma(struct loongson2_mmc_host *host,
+					      struct mmc_data *data)
+{
+	struct loongson2_dma_desc *pdes = (struct loongson2_dma_desc *)host->sg_cpu;
+	struct mmc_host *mmc = mmc_from_priv(host);
+	dma_addr_t next_desc = host->sg_dma;
+	struct scatterlist *sg;
+	int reg_lo, reg_hi;
+	u64 dma_order;
+	int i, ret;
+
+	ret = dma_map_sg(mmc_dev(mmc), data->sg, data->sg_len,
+			 mmc_get_dma_dir(data));
+	if (!ret)
+		return -ENOMEM;
+
+	for_each_sg(data->sg, sg, data->sg_len, i) {
+		pdes[i].len = sg_dma_len(&sg[i]) / 4;
+		pdes[i].step_len = 0;
+		pdes[i].step_times = 1;
+		pdes[i].mem_addr = lower_32_bits(sg_dma_address(&sg[i]));
+		pdes[i].high_mem_addr = upper_32_bits(sg_dma_address(&sg[i]));
+		pdes[i].apb_addr = host->res->start + LOONGSON2_MMC_REG_DATA;
+		pdes[i].cmd = LOONGSON2_MMC_DMA_INT;
+
+		if (data->flags & MMC_DATA_READ) {
+			reg_lo = LOONGSON2_MMC_REG_RDMA_LO;
+			reg_hi = LOONGSON2_MMC_REG_RDMA_HI;
+		} else {
+			pdes[i].cmd |= LOONGSON2_MMC_DMA_DATA_DIR;
+			reg_lo = LOONGSON2_MMC_REG_WDMA_LO;
+			reg_hi = LOONGSON2_MMC_REG_WDMA_HI;
+		}
+
+		next_desc += sizeof(struct loongson2_dma_desc);
+		pdes[i].ndesc_addr = lower_32_bits(next_desc) |
+				     LOONGSON2_MMC_DMA_DESC_EN;
+		pdes[i].high_ndesc_addr = upper_32_bits(next_desc);
+	}
+
+	/* Setting the last descriptor enable bit */
+	pdes[i - 1].ndesc_addr &= ~LOONGSON2_MMC_DMA_DESC_EN;
+
+	dma_order = (host->sg_dma & ~LOONGSON2_MMC_DMA_CONFIG_MASK) |
+		    LOONGSON2_MMC_DMA_64BIT_EN |
+		    LOONGSON2_MMC_DMA_START;
+
+	regmap_write(host->regmap, reg_hi, upper_32_bits(dma_order));
+	regmap_write(host->regmap, reg_lo, lower_32_bits(dma_order));
+
+	return 0;
+}
+
+static int loongson2_mmc_set_internal_dma(struct loongson2_mmc_host *host,
+					  struct platform_device *pdev)
+{
+	host->sg_cpu = dma_alloc_coherent(&pdev->dev, PAGE_SIZE,
+					  &host->sg_dma, GFP_KERNEL);
+	if (!host->sg_cpu)
+		return -ENOMEM;
+
+	memset(host->sg_cpu, 0, PAGE_SIZE);
+	return 0;
+}
+
+static void loongson2_mmc_release_internal_dma(struct loongson2_mmc_host *host,
+					       struct device *dev)
+{
+	dma_free_coherent(dev, PAGE_SIZE, host->sg_cpu, host->sg_dma);
+}
+
+static struct loongson2_mmc_pdata ls2k2000_mmc_pdata = {
+	.regmap_config		= &ls2k2000_mmc_regmap_config,
+	.reorder_cmd_data	= ls2k2000_mmc_reorder_cmd_data,
+	.fix_data_timeout	= ls2k2000_mmc_fix_data_timeout,
+	.setting_dma		= loongson2_mmc_set_internal_dma,
+	.prepare_dma		= loongson2_mmc_prepare_internal_dma,
+	.release_dma		= loongson2_mmc_release_internal_dma,
+};
+
 static int loongson2_mmc_resource_request(struct platform_device *pdev,
 					  struct loongson2_mmc_host *host)
 {
@@ -756,6 +986,7 @@ static void loongson2_mmc_remove(struct platform_device *pdev)
 static const struct of_device_id loongson2_mmc_of_ids[] = {
 	{ .compatible = "loongson,ls2k0500-mmc", .data = &ls2k0500_mmc_pdata },
 	{ .compatible = "loongson,ls2k1000-mmc", .data = &ls2k1000_mmc_pdata },
+	{ .compatible = "loongson,ls2k2000-mmc", .data = &ls2k2000_mmc_pdata },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, loongson2_mmc_of_ids);