sf: ramtron: new spi fram driver

Supports most types that support Read-Id and the FM25H20.

Signed-off-by: Reinhard Meyer <u-boot@emk-elektronik.de>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

1 files changed, 319 insertions, 0 deletions

diff --git a/drivers/mtd/spi/ramtron.c b/drivers/mtd/spi/ramtron.c
new file mode 100644
index 0000000..171390d
--- /dev/null
+++ b/drivers/mtd/spi/ramtron.c
@@ -0,0 +1,319 @@
+/*
+ * (C) Copyright 2010
+ * Reinhard Meyer, EMK Elektronik, reinhard.meyer@emk-elektronik.de
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * Note: RAMTRON SPI FRAMs are ferroelectric, nonvolatile RAMs
+ * with an interface identical to SPI flash devices.
+ * However since they behave like RAM there are no delays or
+ * busy polls required. They can sustain read or write at the
+ * allowed SPI bus speed, which can be 40 MHz for some devices.
+ *
+ * Unfortunately some RAMTRON devices do not have a means of
+ * identifying them. They will leave the SO line undriven when
+ * the READ-ID command is issued. It is therefore mandatory
+ * that the MISO line has a proper pull-up, so that READ-ID
+ * will return a row of 0xff. This 0xff pseudo-id will cause
+ * probes by all vendor specific functions that are designed
+ * to handle it. If the MISO line is not pulled up, READ-ID
+ * could return any random noise, even mimicking another
+ * device.
+ *
+ * We use CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC
+ * to define which device will be assumed after a simple status
+ * register verify. This method is prone to false positive
+ * detection and should therefore be the last to be tried.
+ * Enter it in the last position in the table in spi_flash.c!
+ *
+ * The define CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC both activates
+ * compilation of the special handler and defines the device
+ * to assume.
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <spi_flash.h>
+#include "spi_flash_internal.h"
+
+/* RAMTRON commands common to all devices */
+#define CMD_RAMTRON_WREN	0x06	/* Write Enable */
+#define CMD_RAMTRON_WRDI	0x04	/* Write Disable */
+#define CMD_RAMTRON_RDSR	0x05	/* Read Status Register */
+#define CMD_RAMTRON_WRSR	0x01	/* Write Status Register */
+#define CMD_RAMTRON_READ	0x03	/* Read Data Bytes */
+#define CMD_RAMTRON_WRITE	0x02	/* Write Data Bytes */
+/* not all have those: */
+#define CMD_RAMTRON_FSTRD	0x0b	/* Fast Read (for compatibility - not used here) */
+#define CMD_RAMTRON_SLEEP	0xb9	/* Enter Sleep Mode */
+#define CMD_RAMTRON_RDID	0x9f	/* Read ID */
+#define CMD_RAMTRON_SNR		0xc3	/* Read Serial Number */
+
+/*
+ * Properties of supported FRAMs
+ * Note: speed is currently not used because we have no method to deliver that
+ * value to the upper layers
+ */
+struct ramtron_spi_fram_params {
+	u32	size;		/* size in bytes */
+	u8	addr_len;	/* number of address bytes */
+	u8	merge_cmd;	/* some address bits are in the command byte */
+	u8	id1;		/* device ID 1 (family, density) */
+	u8	id2;		/* device ID 2 (sub, rev, rsvd) */
+	u32	speed;		/* max. SPI clock in Hz */
+	const char *name;	/* name for display and/or matching */
+};
+
+struct ramtron_spi_fram {
+	struct spi_flash flash;
+	const struct ramtron_spi_fram_params *params;
+};
+
+static inline struct ramtron_spi_fram *to_ramtron_spi_fram(struct spi_flash
+							     *flash)
+{
+	return container_of(flash, struct ramtron_spi_fram, flash);
+}
+
+/*
+ * table describing supported FRAM chips:
+ * chips without RDID command must have the values 0xff for id1 and id2
+ */
+static const struct ramtron_spi_fram_params ramtron_spi_fram_table[] = {
+	{
+		.size = 32*1024,
+		.addr_len = 2,
+		.merge_cmd = 0,
+		.id1 = 0x22,
+		.id2 = 0x00,
+		.speed = 40000000,
+		.name = "FM25V02",
+	},
+	{
+		.size = 32*1024,
+		.addr_len = 2,
+		.merge_cmd = 0,
+		.id1 = 0x22,
+		.id2 = 0x01,
+		.speed = 40000000,
+		.name = "FM25VN02",
+	},
+	{
+		.size = 64*1024,
+		.addr_len = 2,
+		.merge_cmd = 0,
+		.id1 = 0x23,
+		.id2 = 0x00,
+		.speed = 40000000,
+		.name = "FM25V05",
+	},
+	{
+		.size = 64*1024,
+		.addr_len = 2,
+		.merge_cmd = 0,
+		.id1 = 0x23,
+		.id2 = 0x01,
+		.speed = 40000000,
+		.name = "FM25VN05",
+	},
+	{
+		.size = 128*1024,
+		.addr_len = 3,
+		.merge_cmd = 0,
+		.id1 = 0x24,
+		.id2 = 0x00,
+		.speed = 40000000,
+		.name = "FM25V10",
+	},
+	{
+		.size = 128*1024,
+		.addr_len = 3,
+		.merge_cmd = 0,
+		.id1 = 0x24,
+		.id2 = 0x01,
+		.speed = 40000000,
+		.name = "FM25VN10",
+	},
+#ifdef CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC
+	{
+		.size = 256*1024,
+		.addr_len = 3,
+		.merge_cmd = 0,
+		.id1 = 0xff,
+		.id2 = 0xff,
+		.speed = 40000000,
+		.name = "FM25H20",
+	},
+#endif
+};
+
+static int ramtron_common(struct spi_flash *flash,
+		u32 offset, size_t len, void *buf, u8 command)
+{
+	struct ramtron_spi_fram *sn = to_ramtron_spi_fram(flash);
+	u8 cmd[4];
+	int cmd_len;
+	int ret;
+
+	if (sn->params->addr_len == 3 && sn->params->merge_cmd == 0) {
+		cmd[0] = command;
+		cmd[1] = offset >> 16;
+		cmd[2] = offset >> 8;
+		cmd[3] = offset;
+		cmd_len = 4;
+	} else if (sn->params->addr_len == 2 && sn->params->merge_cmd == 0) {
+		cmd[0] = command;
+		cmd[1] = offset >> 8;
+		cmd[2] = offset;
+		cmd_len = 3;
+	} else {
+		printf("SF: unsupported addr_len or merge_cmd\n");
+		return -1;
+	}
+
+	/* claim the bus */
+	ret = spi_claim_bus(flash->spi);
+	if (ret) {
+		debug("SF: Unable to claim SPI bus\n");
+		return ret;
+	}
+
+	if (command == CMD_RAMTRON_WRITE) {
+		/* send WREN */
+		ret = spi_flash_cmd(flash->spi, CMD_RAMTRON_WREN, NULL, 0);
+		if (ret < 0) {
+			debug("SF: Enabling Write failed\n");
+			goto releasebus;
+		}
+	}
+
+	/* do the transaction */
+	if (command == CMD_RAMTRON_WRITE)
+		ret = spi_flash_cmd_write(flash->spi, cmd, cmd_len, buf, len);
+	else
+		ret = spi_flash_cmd_read(flash->spi, cmd, cmd_len, buf, len);
+	if (ret < 0)
+		debug("SF: Transaction failed\n");
+
+releasebus:
+	/* release the bus */
+	spi_release_bus(flash->spi);
+	return ret;
+}
+
+static int ramtron_read(struct spi_flash *flash,
+		u32 offset, size_t len, void *buf)
+{
+	return ramtron_common(flash, offset, len, buf,
+		CMD_RAMTRON_READ);
+}
+
+static int ramtron_write(struct spi_flash *flash,
+		u32 offset, size_t len, const void *buf)
+{
+	return ramtron_common(flash, offset, len, (void *)buf,
+		CMD_RAMTRON_WRITE);
+}
+
+int ramtron_erase(struct spi_flash *flash, u32 offset, size_t len)
+{
+	debug("SF: Erase of RAMTRON FRAMs is pointless\n");
+	return -1;
+}
+
+/*
+ * nore: we are called here with idcode pointing to the first non-0x7f byte
+ * already!
+ */
+struct spi_flash *spi_fram_probe_ramtron(struct spi_slave *spi, u8 *idcode)
+{
+	const struct ramtron_spi_fram_params *params;
+	struct ramtron_spi_fram *sn;
+	unsigned int i;
+#ifdef CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC
+	int ret;
+	u8 sr;
+#endif
+
+	/* NOTE: the bus has been claimed before this function is called! */
+	switch (idcode[0]) {
+	case 0xc2:
+		/* JEDEC conformant RAMTRON id */
+		for (i = 0; i < ARRAY_SIZE(ramtron_spi_fram_table); i++) {
+			params = &ramtron_spi_fram_table[i];
+			if (idcode[1] == params->id1 && idcode[2] == params->id2)
+				goto found;
+		}
+		break;
+#ifdef CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC
+	case 0xff:
+		/*
+		 * probably open MISO line, pulled up.
+		 * We COULD have a non JEDEC conformant FRAM here,
+		 * read the status register to verify
+		 */
+		ret = spi_flash_cmd(spi, CMD_RAMTRON_RDSR, &sr, 1);
+		if (ret)
+			return NULL;
+
+		/* Bits 5,4,0 are fixed 0 for all devices */
+		if ((sr & 0x31) != 0x00)
+			return NULL;
+		/* now find the device */
+		for (i = 0; i < ARRAY_SIZE(ramtron_spi_fram_table); i++) {
+			params = &ramtron_spi_fram_table[i];
+			if (!strcmp(params->name, CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC))
+				goto found;
+		}
+		debug("SF: Unsupported non-JEDEC RAMTRON device "
+			CONFIG_SPI_FRAM_RAMTRON_NON_JEDEC "\n");
+		break;
+#endif
+	default:
+		break;
+	}
+
+	/* arriving here means no method has found a device we can handle */
+	debug("SF/ramtron: unsupported device id0=%02x id1=%02x id2=%02x\n",
+		idcode[0], idcode[1], idcode[2]);
+	return NULL;
+
+found:
+	sn = malloc(sizeof(*sn));
+	if (!sn) {
+		debug("SF: Failed to allocate memory\n");
+		return NULL;
+	}
+
+	sn->params = params;
+	sn->flash.spi = spi;
+	sn->flash.name = params->name;
+
+	sn->flash.write = ramtron_write;
+	sn->flash.read = ramtron_read;
+	sn->flash.erase = ramtron_erase;
+	sn->flash.size = params->size;
+
+	printf("SF: Detected %s with size ", params->name);
+	print_size(sn->flash.size, "\n");
+
+	return &sn->flash;
+}