mmc: add generic mmc spi driver

This patch supports mmc/sd card with spi interface. It is based on
the generic mmc framework. It works with SDHC and supports multi
blocks read/write.

The crc checksum on data packet is enabled with the def,

There is a subcomamnd "mmc_spi" to setup spi bus and cs at run time.
Signed-off-by: NThomas Chou <thomas@wytron.com.tw>
Signed-off-by: NAndy Fleming <afleming@freescale.com>

common/Makefile

@@ -118,6 +118,7 @@ COBJS-$(CONFIG_CMD_MII) += miiphyutil.o
 COBJS-$(CONFIG_CMD_MII) += cmd_mii.o
 COBJS-$(CONFIG_CMD_MISC) += cmd_misc.o
 COBJS-$(CONFIG_CMD_MMC) += cmd_mmc.o
+COBJS-$(CONFIG_CMD_MMC_SPI) += cmd_mmc_spi.o
 COBJS-$(CONFIG_MP) += cmd_mp.o
 COBJS-$(CONFIG_CMD_MTDPARTS) += cmd_mtdparts.o
 COBJS-$(CONFIG_CMD_NAND) += cmd_nand.o

common/cmd_mmc_spi.c

+/*
+ * Command for mmc_spi setup.
+ *
+ * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <common.h>
+#include <mmc.h>
+#include <spi.h>
+
+#ifndef CONFIG_MMC_SPI_BUS
+# define CONFIG_MMC_SPI_BUS 0
+#endif
+#ifndef CONFIG_MMC_SPI_CS
+# define CONFIG_MMC_SPI_CS 1
+#endif
+/* in SPI mode, MMC speed limit is 20MHz, while SD speed limit is 25MHz */
+#ifndef CONFIG_MMC_SPI_SPEED
+# define CONFIG_MMC_SPI_SPEED 25000000
+#endif
+/* MMC and SD specs only seem to care that sampling is on the
+ * rising edge ... meaning SPI modes 0 or 3.  So either SPI mode
+ * should be legit.  We'll use mode 0 since the steady state is 0,
+ * which is appropriate for hotplugging, unless the platform data
+ * specify mode 3 (if hardware is not compatible to mode 0).
+ */
+#ifndef CONFIG_MMC_SPI_MODE
+# define CONFIG_MMC_SPI_MODE SPI_MODE_0
+#endif
+
+static int do_mmc_spi(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	uint bus = CONFIG_MMC_SPI_BUS;
+	uint cs = CONFIG_MMC_SPI_CS;
+	uint speed = CONFIG_MMC_SPI_SPEED;
+	uint mode = CONFIG_MMC_SPI_MODE;
+	char *endp;
+	struct mmc *mmc;
+
+	if (argc < 2)
+		goto usage;
+
+	cs = simple_strtoul(argv[1], &endp, 0);
+	if (*argv[1] == 0 || (*endp != 0 && *endp != ':'))
+		goto usage;
+	if (*endp == ':') {
+		if (endp[1] == 0)
+			goto usage;
+		bus = cs;
+		cs = simple_strtoul(endp + 1, &endp, 0);
+		if (*endp != 0)
+			goto usage;
+	}
+	if (argc >= 3) {
+		speed = simple_strtoul(argv[2], &endp, 0);
+		if (*argv[2] == 0 || *endp != 0)
+			goto usage;
+	}
+	if (argc >= 4) {
+		mode = simple_strtoul(argv[3], &endp, 16);
+		if (*argv[3] == 0 || *endp != 0)
+			goto usage;
+	}
+	if (!spi_cs_is_valid(bus, cs)) {
+		printf("Invalid SPI bus %u cs %u\n", bus, cs);
+		return 1;
+	}
+
+	mmc = mmc_spi_init(bus, cs, speed, mode);
+	if (!mmc) {
+		printf("Failed to create MMC Device\n");
+		return 1;
+	}
+	printf("%s: %d at %u:%u hz %u mode %u\n", mmc->name, mmc->block_dev.dev,
+	       bus, cs, speed, mode);
+	return 0;
+
+usage:
+	cmd_usage(cmdtp);
+	return 1;
+}
+
+U_BOOT_CMD(
+	mmc_spi,	4,	0,	do_mmc_spi,
+	"mmc_spi setup",
+	"[bus:]cs [hz] [mode]	- setup mmc_spi device"
+);

drivers/mmc/Makefile

@@ -31,6 +31,7 @@ COBJS-$(CONFIG_DAVINCI_MMC) += davinci_mmc.o
 COBJS-$(CONFIG_FSL_ESDHC) += fsl_esdhc.o
 COBJS-$(CONFIG_GENERIC_MMC) += mmc.o
 COBJS-$(CONFIG_GENERIC_ATMEL_MCI) += gen_atmel_mci.o
+COBJS-$(CONFIG_MMC_SPI) += mmc_spi.o
 COBJS-$(CONFIG_MXC_MMC) += mxcmmc.o
 COBJS-$(CONFIG_OMAP3_MMC) += omap3_mmc.o
 COBJS-$(CONFIG_OMAP_HSMMC) += omap_hsmmc.o

drivers/mmc/mmc.c

@@ -117,7 +117,10 @@ mmc_write_blocks(struct mmc *mmc, ulong start, lbaint_t blkcnt, const void*src)
 		return 0;
 	}
 
-	if (blkcnt > 1) {
+	/* SPI multiblock writes terminate using a special
+	 * token, not a STOP_TRANSMISSION request.
+	 */
+	if (!mmc_host_is_spi(mmc) && blkcnt > 1) {
 		cmd.cmdidx = MMC_CMD_STOP_TRANSMISSION;
 		cmd.cmdarg = 0;
 		cmd.resp_type = MMC_RSP_R1b;
@@ -279,7 +282,8 @@ sd_send_op_cond(struct mmc *mmc)
 		 * how to manage low voltages SD card is not yet
 		 * specified.
 		 */
-		cmd.cmdarg = mmc->voltages & 0xff8000;
+		cmd.cmdarg = mmc_host_is_spi(mmc) ? 0 :
+			(mmc->voltages & 0xff8000);
 
 		if (mmc->version == SD_VERSION_2)
 			cmd.cmdarg |= OCR_HCS;
@@ -298,6 +302,18 @@ sd_send_op_cond(struct mmc *mmc)
 	if (mmc->version != SD_VERSION_2)
 		mmc->version = SD_VERSION_1_0;
 
+	if (mmc_host_is_spi(mmc)) { /* read OCR for spi */
+		cmd.cmdidx = MMC_CMD_SPI_READ_OCR;
+		cmd.resp_type = MMC_RSP_R3;
+		cmd.cmdarg = 0;
+		cmd.flags = 0;
+
+		err = mmc_send_cmd(mmc, &cmd, NULL);
+
+		if (err)
+			return err;
+	}
+
 	mmc->ocr = cmd.response[0];
 
 	mmc->high_capacity = ((mmc->ocr & OCR_HCS) == OCR_HCS);
@@ -318,7 +334,8 @@ int mmc_send_op_cond(struct mmc *mmc)
 	do {
 		cmd.cmdidx = MMC_CMD_SEND_OP_COND;
 		cmd.resp_type = MMC_RSP_R3;
-		cmd.cmdarg = OCR_HCS | mmc->voltages;
+		cmd.cmdarg = OCR_HCS | (mmc_host_is_spi(mmc) ? 0 :
+					mmc->voltages);
 		cmd.flags = 0;
 
 		err = mmc_send_cmd(mmc, &cmd, NULL);
@@ -332,6 +349,18 @@ int mmc_send_op_cond(struct mmc *mmc)
 	if (timeout <= 0)
 		return UNUSABLE_ERR;
 
+	if (mmc_host_is_spi(mmc)) { /* read OCR for spi */
+		cmd.cmdidx = MMC_CMD_SPI_READ_OCR;
+		cmd.resp_type = MMC_RSP_R3;
+		cmd.cmdarg = 0;
+		cmd.flags = 0;
+
+		err = mmc_send_cmd(mmc, &cmd, NULL);
+
+		if (err)
+			return err;
+	}
+
 	mmc->version = MMC_VERSION_UNKNOWN;
 	mmc->ocr = cmd.response[0];
 
@@ -387,6 +416,9 @@ int mmc_change_freq(struct mmc *mmc)
 
 	mmc->card_caps = 0;
 
+	if (mmc_host_is_spi(mmc))
+		return 0;
+
 	/* Only version 4 supports high-speed */
 	if (mmc->version < MMC_VERSION_4)
 		return 0;
@@ -460,6 +492,9 @@ int sd_change_freq(struct mmc *mmc)
 
 	mmc->card_caps = 0;
 
+	if (mmc_host_is_spi(mmc))
+		return 0;
+
 	/* Read the SCR to find out if this card supports higher speeds */
 	cmd.cmdidx = MMC_CMD_APP_CMD;
 	cmd.resp_type = MMC_RSP_R1;
@@ -610,8 +645,22 @@ int mmc_startup(struct mmc *mmc)
 	struct mmc_cmd cmd;
 	char ext_csd[512];
 
+#ifdef CONFIG_MMC_SPI_CRC_ON
+	if (mmc_host_is_spi(mmc)) { /* enable CRC check for spi */
+		cmd.cmdidx = MMC_CMD_SPI_CRC_ON_OFF;
+		cmd.resp_type = MMC_RSP_R1;
+		cmd.cmdarg = 1;
+		cmd.flags = 0;
+		err = mmc_send_cmd(mmc, &cmd, NULL);
+
+		if (err)
+			return err;
+	}
+#endif
+
 	/* Put the Card in Identify Mode */
-	cmd.cmdidx = MMC_CMD_ALL_SEND_CID;
+	cmd.cmdidx = mmc_host_is_spi(mmc) ? MMC_CMD_SEND_CID :
+		MMC_CMD_ALL_SEND_CID; /* cmd not supported in spi */
 	cmd.resp_type = MMC_RSP_R2;
 	cmd.cmdarg = 0;
 	cmd.flags = 0;
@@ -628,6 +677,7 @@ int mmc_startup(struct mmc *mmc)
 	 * For SD cards, get the Relatvie Address.
 	 * This also puts the cards into Standby State
 	 */
+	if (!mmc_host_is_spi(mmc)) { /* cmd not supported in spi */
 		cmd.cmdidx = SD_CMD_SEND_RELATIVE_ADDR;
 		cmd.cmdarg = mmc->rca << 16;
 		cmd.resp_type = MMC_RSP_R6;
@@ -640,6 +690,7 @@ int mmc_startup(struct mmc *mmc)
 
 		if (IS_SD(mmc))
 			mmc->rca = (cmd.response[0] >> 16) & 0xffff;
+	}
 
 	/* Get the Card-Specific Data */
 	cmd.cmdidx = MMC_CMD_SEND_CSD;
@@ -715,6 +766,7 @@ int mmc_startup(struct mmc *mmc)
 		mmc->write_bl_len = 512;
 
 	/* Select the card, and put it into Transfer Mode */
+	if (!mmc_host_is_spi(mmc)) { /* cmd not supported in spi */
 		cmd.cmdidx = MMC_CMD_SELECT_CARD;
 		cmd.resp_type = MMC_RSP_R1b;
 		cmd.cmdarg = mmc->rca << 16;
@@ -723,6 +775,7 @@ int mmc_startup(struct mmc *mmc)
 
 		if (err)
 			return err;
+	}
 
 	if (!IS_SD(mmc) && (mmc->version >= MMC_VERSION_4)) {
 		/* check  ext_csd version and capacity */

drivers/mmc/mmc_spi.c

+/*
+ * generic mmc spi driver
+ *
+ * Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
+ * Licensed under the GPL-2 or later.
+ */
+#include <common.h>
+#include <malloc.h>
+#include <part.h>
+#include <mmc.h>
+#include <spi.h>
+#include <crc.h>
+#include <linux/crc7.h>
+#include <linux/byteorder/swab.h>
+
+/* MMC/SD in SPI mode reports R1 status always */
+#define R1_SPI_IDLE		(1 << 0)
+#define R1_SPI_ERASE_RESET	(1 << 1)
+#define R1_SPI_ILLEGAL_COMMAND	(1 << 2)
+#define R1_SPI_COM_CRC		(1 << 3)
+#define R1_SPI_ERASE_SEQ	(1 << 4)
+#define R1_SPI_ADDRESS		(1 << 5)
+#define R1_SPI_PARAMETER	(1 << 6)
+/* R1 bit 7 is always zero, reuse this bit for error */
+#define R1_SPI_ERROR		(1 << 7)
+
+/* Response tokens used to ack each block written: */
+#define SPI_MMC_RESPONSE_CODE(x)	((x) & 0x1f)
+#define SPI_RESPONSE_ACCEPTED		((2 << 1)|1)
+#define SPI_RESPONSE_CRC_ERR		((5 << 1)|1)
+#define SPI_RESPONSE_WRITE_ERR		((6 << 1)|1)
+
+/* Read and write blocks start with these tokens and end with crc;
+ * on error, read tokens act like a subset of R2_SPI_* values.
+ */
+#define SPI_TOKEN_SINGLE	0xfe	/* single block r/w, multiblock read */
+#define SPI_TOKEN_MULTI_WRITE	0xfc	/* multiblock write */
+#define SPI_TOKEN_STOP_TRAN	0xfd	/* terminate multiblock write */
+
+/* MMC SPI commands start with a start bit "0" and a transmit bit "1" */
+#define MMC_SPI_CMD(x) (0x40 | (x & 0x3f))
+
+/* bus capability */
+#define MMC_SPI_VOLTAGE (MMC_VDD_32_33 | MMC_VDD_33_34)
+#define MMC_SPI_MIN_CLOCK 400000 /* 400KHz to meet MMC spec */
+
+/* timeout value */
+#define CTOUT 8
+#define RTOUT 3000000 /* 1 sec */
+#define WTOUT 3000000 /* 1 sec */
+
+static uint mmc_spi_sendcmd(struct mmc *mmc, ushort cmdidx, u32 cmdarg)
+{
+	struct spi_slave *spi = mmc->priv;
+	u8 cmdo[7];
+	u8 r1;
+	int i;
+	cmdo[0] = 0xff;
+	cmdo[1] = MMC_SPI_CMD(cmdidx);
+	cmdo[2] = cmdarg >> 24;
+	cmdo[3] = cmdarg >> 16;
+	cmdo[4] = cmdarg >> 8;
+	cmdo[5] = cmdarg;
+	cmdo[6] = (crc7(0, &cmdo[1], 5) << 1) | 0x01;
+	spi_xfer(spi, sizeof(cmdo) * 8, cmdo, NULL, 0);
+	for (i = 0; i < CTOUT; i++) {
+		spi_xfer(spi, 1 * 8, NULL, &r1, 0);
+		if (i && (r1 & 0x80) == 0) /* r1 response */
+			break;
+	}
+	debug("%s:cmd%d resp%d %x\n", __func__, cmdidx, i, r1);
+	return r1;
+}
+
+static uint mmc_spi_readdata(struct mmc *mmc, void *xbuf,
+				u32 bcnt, u32 bsize)
+{
+	struct spi_slave *spi = mmc->priv;
+	u8 *buf = xbuf;
+	u8 r1;
+	u16 crc;
+	int i;
+	while (bcnt--) {
+		for (i = 0; i < RTOUT; i++) {
+			spi_xfer(spi, 1 * 8, NULL, &r1, 0);
+			if (r1 != 0xff) /* data token */
+				break;
+		}
+		debug("%s:tok%d %x\n", __func__, i, r1);
+		if (r1 == SPI_TOKEN_SINGLE) {
+			spi_xfer(spi, bsize * 8, NULL, buf, 0);
+			spi_xfer(spi, 2 * 8, NULL, &crc, 0);
+#ifdef CONFIG_MMC_SPI_CRC_ON
+			if (swab16(cyg_crc16(buf, bsize)) != crc) {
+				debug("%s: CRC error\n", mmc->name);
+				r1 = R1_SPI_COM_CRC;
+				break;
+			}
+#endif
+			r1 = 0;
+		} else {
+			r1 = R1_SPI_ERROR;
+			break;
+		}
+		buf += bsize;
+	}
+	return r1;
+}
+
+static uint mmc_spi_writedata(struct mmc *mmc, const void *xbuf,
+			      u32 bcnt, u32 bsize, int multi)
+{
+	struct spi_slave *spi = mmc->priv;
+	const u8 *buf = xbuf;
+	u8 r1;
+	u16 crc;
+	u8 tok[2];
+	int i;
+	tok[0] = 0xff;
+	tok[1] = multi ? SPI_TOKEN_MULTI_WRITE : SPI_TOKEN_SINGLE;
+	while (bcnt--) {
+#ifdef CONFIG_MMC_SPI_CRC_ON
+		crc = swab16(cyg_crc16((u8 *)buf, bsize));
+#endif
+		spi_xfer(spi, 2 * 8, tok, NULL, 0);
+		spi_xfer(spi, bsize * 8, buf, NULL, 0);
+		spi_xfer(spi, 2 * 8, &crc, NULL, 0);
+		for (i = 0; i < CTOUT; i++) {
+			spi_xfer(spi, 1 * 8, NULL, &r1, 0);
+			if ((r1 & 0x10) == 0) /* response token */
+				break;
+		}
+		debug("%s:tok%d %x\n", __func__, i, r1);
+		if (SPI_MMC_RESPONSE_CODE(r1) == SPI_RESPONSE_ACCEPTED) {
+			for (i = 0; i < WTOUT; i++) { /* wait busy */
+				spi_xfer(spi, 1 * 8, NULL, &r1, 0);
+				if (i && r1 == 0xff) {
+					r1 = 0;
+					break;
+				}
+			}
+			if (i == WTOUT) {
+				debug("%s:wtout %x\n", __func__, r1);
+				r1 = R1_SPI_ERROR;
+				break;
+			}
+		} else {
+			debug("%s: err %x\n", __func__, r1);
+			r1 = R1_SPI_COM_CRC;
+			break;
+		}
+		buf += bsize;
+	}
+	if (multi && bcnt == -1) { /* stop multi write */
+		tok[1] = SPI_TOKEN_STOP_TRAN;
+		spi_xfer(spi, 2 * 8, tok, NULL, 0);
+		for (i = 0; i < WTOUT; i++) { /* wait busy */
+			spi_xfer(spi, 1 * 8, NULL, &r1, 0);
+			if (i && r1 == 0xff) {
+				r1 = 0;
+				break;
+			}
+		}
+		if (i == WTOUT) {
+			debug("%s:wstop %x\n", __func__, r1);
+			r1 = R1_SPI_ERROR;
+		}
+	}
+	return r1;
+}
+
+static int mmc_spi_request(struct mmc *mmc, struct mmc_cmd *cmd,
+		struct mmc_data *data)
+{
+	struct spi_slave *spi = mmc->priv;
+	u8 r1;
+	int i;
+	int ret = 0;
+	debug("%s:cmd%d %x %x %x\n", __func__,
+	      cmd->cmdidx, cmd->resp_type, cmd->cmdarg, cmd->flags);
+	spi_claim_bus(spi);
+	spi_cs_activate(spi);
+	r1 = mmc_spi_sendcmd(mmc, cmd->cmdidx, cmd->cmdarg);
+	if (r1 == 0xff) { /* no response */
+		ret = NO_CARD_ERR;
+		goto done;
+	} else if (r1 & R1_SPI_COM_CRC) {
+		ret = COMM_ERR;
+		goto done;
+	} else if (r1 & ~R1_SPI_IDLE) { /* other errors */
+		ret = TIMEOUT;
+		goto done;
+	} else if (cmd->resp_type == MMC_RSP_R2) {
+		r1 = mmc_spi_readdata(mmc, cmd->response, 1, 16);
+		for (i = 0; i < 4; i++)
+			cmd->response[i] = swab32(cmd->response[i]);
+		debug("r128 %x %x %x %x\n", cmd->response[0], cmd->response[1],
+		      cmd->response[2], cmd->response[3]);
+	} else if (!data) {
+		switch (cmd->cmdidx) {
+		case SD_CMD_APP_SEND_OP_COND:
+		case MMC_CMD_SEND_OP_COND:
+			cmd->response[0] = (r1 & R1_SPI_IDLE) ? 0 : OCR_BUSY;
+			break;
+		case SD_CMD_SEND_IF_COND:
+		case MMC_CMD_SPI_READ_OCR:
+			spi_xfer(spi, 4 * 8, NULL, cmd->response, 0);
+			cmd->response[0] = swab32(cmd->response[0]);
+			debug("r32 %x\n", cmd->response[0]);
+			break;
+		}
+	} else {
+		debug("%s:data %x %x %x\n", __func__,
+		      data->flags, data->blocks, data->blocksize);
+		if (data->flags == MMC_DATA_READ)
+			r1 = mmc_spi_readdata(mmc, data->dest,
+				data->blocks, data->blocksize);
+		else if  (data->flags == MMC_DATA_WRITE)
+			r1 = mmc_spi_writedata(mmc, data->src,
+				data->blocks, data->blocksize,
+				(cmd->cmdidx == MMC_CMD_WRITE_MULTIPLE_BLOCK));
+		if (r1 & R1_SPI_COM_CRC)
+			ret = COMM_ERR;
+		else if (r1) /* other errors */
+			ret = TIMEOUT;
+	}
+done:
+	spi_cs_deactivate(spi);
+	spi_release_bus(spi);
+	return ret;
+}
+
+static void mmc_spi_set_ios(struct mmc *mmc)
+{
+	struct spi_slave *spi = mmc->priv;
+	debug("%s: clock %u\n", __func__, mmc->clock);
+	if (mmc->clock)
+		spi_set_speed(spi, mmc->clock);
+}
+
+static int mmc_spi_init_p(struct mmc *mmc)
+{
+	struct spi_slave *spi = mmc->priv;
+	mmc->clock = 0;
+	spi_set_speed(spi, MMC_SPI_MIN_CLOCK);
+	spi_claim_bus(spi);
+	/* cs deactivated for 100+ clock */
+	spi_xfer(spi, 18 * 8, NULL, NULL, 0);
+	spi_release_bus(spi);
+	return 0;
+}
+
+struct mmc *mmc_spi_init(uint bus, uint cs, uint speed, uint mode)
+{
+	struct mmc *mmc;
+
+	mmc = malloc(sizeof(*mmc));
+	if (!mmc)
+		return NULL;
+	memset(mmc, 0, sizeof(*mmc));
+	mmc->priv = spi_setup_slave(bus, cs, speed, mode);
+	if (!mmc->priv) {
+		free(mmc);
+		return NULL;
+	}
+	sprintf(mmc->name, "MMC_SPI");
+	mmc->send_cmd = mmc_spi_request;
+	mmc->set_ios = mmc_spi_set_ios;
+	mmc->init = mmc_spi_init_p;
+	mmc->host_caps = MMC_MODE_SPI;
+
+	mmc->voltages = MMC_SPI_VOLTAGE;
+	mmc->f_max = speed;
+	mmc->f_min = MMC_SPI_MIN_CLOCK;
+	mmc->block_dev.part_type = PART_TYPE_DOS;
+
+	mmc_register(mmc);
+
+	return mmc;
+}

include/mmc.h

@@ -44,6 +44,7 @@
 #define MMC_MODE_HS_52MHz	0x010
 #define MMC_MODE_4BIT		0x100
 #define MMC_MODE_8BIT		0x200
+#define MMC_MODE_SPI		0x400
 
 #define SD_DATA_4BIT	0x00040000
 
@@ -75,6 +76,8 @@
 #define MMC_CMD_WRITE_SINGLE_BLOCK	24
 #define MMC_CMD_WRITE_MULTIPLE_BLOCK	25
 #define MMC_CMD_APP_CMD			55
+#define MMC_CMD_SPI_READ_OCR		58
+#define MMC_CMD_SPI_CRC_ON_OFF		59
 
 #define SD_CMD_SEND_RELATIVE_ADDR	3
 #define SD_CMD_SWITCH_FUNC		6
@@ -291,6 +294,8 @@ int board_mmc_getcd(u8 *cd, struct mmc *mmc);
 
 #ifdef CONFIG_GENERIC_MMC
 int atmel_mci_init(void *regs);
+#define mmc_host_is_spi(mmc)	((mmc)->host_caps & MMC_MODE_SPI)
+struct mmc *mmc_spi_init(uint bus, uint cs, uint speed, uint mode);
 #else
 int mmc_legacy_init(int verbose);
 #endif