SPI Flash subsystem
This adds a new SPI flash subsystem.
Currently, only AT45 DataFlash in non-power-of-two mode is supported,
but some preliminary support for other flash types is in place as
well.
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
diff --git a/drivers/mtd/spi/atmel.c b/drivers/mtd/spi/atmel.c
new file mode 100644
index 0000000..fb7a4a9
--- /dev/null
+++ b/drivers/mtd/spi/atmel.c
@@ -0,0 +1,362 @@
+/*
+ * Atmel SPI DataFlash support
+ *
+ * Copyright (C) 2008 Atmel Corporation
+ */
+#define DEBUG
+#include <common.h>
+#include <malloc.h>
+#include <spi_flash.h>
+
+#include "spi_flash_internal.h"
+
+/* AT45-specific commands */
+#define CMD_AT45_READ_STATUS 0xd7
+#define CMD_AT45_ERASE_PAGE 0x81
+#define CMD_AT45_LOAD_PROG_BUF1 0x82
+#define CMD_AT45_LOAD_BUF1 0x84
+#define CMD_AT45_LOAD_PROG_BUF2 0x85
+#define CMD_AT45_LOAD_BUF2 0x87
+#define CMD_AT45_PROG_BUF1 0x88
+#define CMD_AT45_PROG_BUF2 0x89
+
+/* AT45 status register bits */
+#define AT45_STATUS_P2_PAGE_SIZE (1 << 0)
+#define AT45_STATUS_READY (1 << 7)
+
+/* DataFlash family IDs, as obtained from the second idcode byte */
+#define DF_FAMILY_AT26F 0
+#define DF_FAMILY_AT45 1
+#define DF_FAMILY_AT26DF 2 /* AT25DF and AT26DF */
+
+struct atmel_spi_flash_params {
+ u8 idcode1;
+ /* Log2 of page size in power-of-two mode */
+ u8 l2_page_size;
+ u8 pages_per_block;
+ u8 blocks_per_sector;
+ u8 nr_sectors;
+ const char *name;
+};
+
+struct atmel_spi_flash {
+ const struct atmel_spi_flash_params *params;
+ struct spi_flash flash;
+};
+
+static inline struct atmel_spi_flash *
+to_atmel_spi_flash(struct spi_flash *flash)
+{
+ return container_of(flash, struct atmel_spi_flash, flash);
+}
+
+static const struct atmel_spi_flash_params atmel_spi_flash_table[] = {
+ {
+ .idcode1 = 0x28,
+ .l2_page_size = 10,
+ .pages_per_block = 8,
+ .blocks_per_sector = 32,
+ .nr_sectors = 32,
+ .name = "AT45DB642D",
+ },
+};
+
+static int at45_wait_ready(struct spi_flash *flash, unsigned long timeout)
+{
+ struct spi_slave *spi = flash->spi;
+ unsigned long timebase;
+ int ret;
+ u8 cmd = CMD_AT45_READ_STATUS;
+ u8 status;
+
+ timebase = get_timer(0);
+
+ ret = spi_xfer(spi, 8, &cmd, NULL, SPI_XFER_BEGIN);
+ if (ret)
+ return -1;
+
+ do {
+ ret = spi_xfer(spi, 8, NULL, &status, 0);
+ if (ret)
+ return -1;
+
+ if (status & AT45_STATUS_READY)
+ break;
+ } while (get_timer(timebase) < timeout);
+
+ /* Deactivate CS */
+ spi_xfer(spi, 0, NULL, NULL, SPI_XFER_END);
+
+ if (status & AT45_STATUS_READY)
+ return 0;
+
+ /* Timed out */
+ return -1;
+}
+
+/*
+ * Assemble the address part of a command for AT45 devices in
+ * non-power-of-two page size mode.
+ */
+static void at45_build_address(struct atmel_spi_flash *asf, u8 *cmd, u32 offset)
+{
+ unsigned long page_addr;
+ unsigned long byte_addr;
+ unsigned long page_size;
+ unsigned int page_shift;
+
+ /*
+ * The "extra" space per page is the power-of-two page size
+ * divided by 32.
+ */
+ page_shift = asf->params->l2_page_size;
+ page_size = (1 << page_shift) + (1 << (page_shift - 5));
+ page_shift++;
+ page_addr = offset / page_size;
+ byte_addr = offset % page_size;
+
+ cmd[0] = page_addr >> (16 - page_shift);
+ cmd[1] = page_addr << (page_shift - 8) | (byte_addr >> 8);
+ cmd[2] = byte_addr;
+}
+
+static int dataflash_read_fast_p2(struct spi_flash *flash,
+ u32 offset, size_t len, void *buf)
+{
+ u8 cmd[5];
+
+ cmd[0] = CMD_READ_ARRAY_FAST;
+ cmd[1] = offset >> 16;
+ cmd[2] = offset >> 8;
+ cmd[3] = offset;
+ cmd[4] = 0x00;
+
+ return spi_flash_read_common(flash, cmd, sizeof(cmd), buf, len);
+}
+
+static int dataflash_read_fast_at45(struct spi_flash *flash,
+ u32 offset, size_t len, void *buf)
+{
+ struct atmel_spi_flash *asf = to_atmel_spi_flash(flash);
+ u8 cmd[5];
+
+ cmd[0] = CMD_READ_ARRAY_FAST;
+ at45_build_address(asf, cmd + 1, offset);
+ cmd[4] = 0x00;
+
+ return spi_flash_read_common(flash, cmd, sizeof(cmd), buf, len);
+}
+
+static int dataflash_write_at45(struct spi_flash *flash,
+ u32 offset, size_t len, const void *buf)
+{
+ struct atmel_spi_flash *asf = to_atmel_spi_flash(flash);
+ unsigned long page_addr;
+ unsigned long byte_addr;
+ unsigned long page_size;
+ unsigned int page_shift;
+ size_t chunk_len;
+ size_t actual;
+ int ret;
+ u8 cmd[4];
+
+ page_shift = asf->params->l2_page_size;
+ page_size = (1 << page_shift) + (1 << (page_shift - 5));
+ page_shift++;
+ page_addr = offset / page_size;
+ byte_addr = offset % page_size;
+
+ ret = spi_claim_bus(flash->spi);
+ if (ret) {
+ debug("SF: Unable to claim SPI bus\n");
+ return ret;
+ }
+
+ for (actual = 0; actual < len; actual += chunk_len) {
+ chunk_len = min(len - actual, page_size - byte_addr);
+
+ /* Use the same address bits for both commands */
+ cmd[0] = CMD_AT45_LOAD_BUF1;
+ cmd[1] = page_addr >> (16 - page_shift);
+ cmd[2] = page_addr << (page_shift - 8) | (byte_addr >> 8);
+ cmd[3] = byte_addr;
+
+ ret = spi_flash_cmd_write(flash->spi, cmd, 4,
+ buf + actual, chunk_len);
+ if (ret < 0) {
+ debug("SF: Loading AT45 buffer failed\n");
+ goto out;
+ }
+
+ cmd[0] = CMD_AT45_PROG_BUF1;
+ ret = spi_flash_cmd_write(flash->spi, cmd, 4, NULL, 0);
+ if (ret < 0) {
+ debug("SF: AT45 page programming failed\n");
+ goto out;
+ }
+
+ ret = at45_wait_ready(flash, SPI_FLASH_PROG_TIMEOUT);
+ if (ret < 0) {
+ debug("SF: AT45 page programming timed out\n");
+ goto out;
+ }
+
+ page_addr++;
+ byte_addr = 0;
+ }
+
+ debug("SF: AT45: Successfully programmed %u bytes @ 0x%x\n",
+ len, offset);
+ ret = 0;
+
+out:
+ spi_release_bus(flash->spi);
+ return ret;
+}
+
+int dataflash_erase_at45(struct spi_flash *flash, u32 offset, size_t len)
+{
+ struct atmel_spi_flash *asf = to_atmel_spi_flash(flash);
+ unsigned long page_addr;
+ unsigned long page_size;
+ unsigned int page_shift;
+ size_t actual;
+ int ret;
+ u8 cmd[4];
+
+ /*
+ * TODO: This function currently uses page erase only. We can
+ * probably speed things up by using block and/or sector erase
+ * when possible.
+ */
+
+ page_shift = asf->params->l2_page_size;
+ page_size = (1 << page_shift) + (1 << (page_shift - 5));
+ page_shift++;
+ page_addr = offset / page_size;
+
+ if (offset % page_size || len % page_size) {
+ debug("SF: Erase offset/length not multiple of page size\n");
+ return -1;
+ }
+
+ cmd[0] = CMD_AT45_ERASE_PAGE;
+ cmd[3] = 0x00;
+
+ ret = spi_claim_bus(flash->spi);
+ if (ret) {
+ debug("SF: Unable to claim SPI bus\n");
+ return ret;
+ }
+
+ for (actual = 0; actual < len; actual += page_size) {
+ cmd[1] = page_addr >> (16 - page_shift);
+ cmd[2] = page_addr << (page_shift - 8);
+
+ ret = spi_flash_cmd_write(flash->spi, cmd, 4, NULL, 0);
+ if (ret < 0) {
+ debug("SF: AT45 page erase failed\n");
+ goto out;
+ }
+
+ ret = at45_wait_ready(flash, SPI_FLASH_PAGE_ERASE_TIMEOUT);
+ if (ret < 0) {
+ debug("SF: AT45 page erase timed out\n");
+ goto out;
+ }
+
+ page_addr++;
+ }
+
+ debug("SF: AT45: Successfully erased %u bytes @ 0x%x\n",
+ len, offset);
+ ret = 0;
+
+out:
+ spi_release_bus(flash->spi);
+ return ret;
+}
+
+struct spi_flash *spi_flash_probe_atmel(struct spi_slave *spi, u8 *idcode)
+{
+ const struct atmel_spi_flash_params *params;
+ unsigned long page_size;
+ unsigned int family;
+ struct atmel_spi_flash *asf;
+ unsigned int i;
+ int ret;
+ u8 status;
+
+ for (i = 0; i < ARRAY_SIZE(atmel_spi_flash_table); i++) {
+ params = &atmel_spi_flash_table[i];
+ if (params->idcode1 == idcode[1])
+ break;
+ }
+
+ if (i == ARRAY_SIZE(atmel_spi_flash_table)) {
+ debug("SF: Unsupported DataFlash ID %02x\n",
+ idcode[1]);
+ return NULL;
+ }
+
+ asf = malloc(sizeof(struct atmel_spi_flash));
+ if (!asf) {
+ debug("SF: Failed to allocate memory\n");
+ return NULL;
+ }
+
+ asf->params = params;
+ asf->flash.spi = spi;
+ asf->flash.name = params->name;
+
+ /* Assuming power-of-two page size initially. */
+ page_size = 1 << params->l2_page_size;
+
+ family = idcode[1] >> 5;
+
+ switch (family) {
+ case DF_FAMILY_AT45:
+ /*
+ * AT45 chips have configurable page size. The status
+ * register indicates which configuration is active.
+ */
+ ret = spi_flash_cmd(spi, CMD_AT45_READ_STATUS, &status, 1);
+ if (ret)
+ goto err;
+
+ debug("SF: AT45 status register: %02x\n", status);
+
+ if (!(status & AT45_STATUS_P2_PAGE_SIZE)) {
+ asf->flash.read = dataflash_read_fast_at45;
+ asf->flash.write = dataflash_write_at45;
+ asf->flash.erase = dataflash_erase_at45;
+ page_size += 1 << (params->l2_page_size - 5);
+ } else {
+ asf->flash.read = dataflash_read_fast_p2;
+ }
+
+ break;
+
+ case DF_FAMILY_AT26F:
+ case DF_FAMILY_AT26DF:
+ asf->flash.read = dataflash_read_fast_p2;
+ break;
+
+ default:
+ debug("SF: Unsupported DataFlash family %u\n", family);
+ goto err;
+ }
+
+ asf->flash.size = page_size * params->pages_per_block
+ * params->blocks_per_sector
+ * params->nr_sectors;
+
+ debug("SF: Detected %s with page size %u, total %u bytes\n",
+ params->name, page_size, asf->flash.size);
+
+ return &asf->flash;
+
+err:
+ free(asf);
+ return NULL;
+}