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: Thomas Chou <thomas@wytron.com.tw>
Signed-off-by: Andy Fleming <afleming@freescale.com>

1 files changed, 88 insertions, 0 deletions

diff --git a/common/cmd_mmc_spi.c b/common/cmd_mmc_spi.c
new file mode 100644
index 000000000..63fe31337
--- /dev/null
+++ b/common/cmd_mmc_spi.c
@@ -0,0 +1,88 @@
+/*
+ * 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"
+);