dm: sf: Add Atmel DataFlash spi flash driver
authorHaikun Wang <Haikun.Wang@freescale.com>
Fri, 26 Jun 2015 11:30:27 +0000 (19:30 +0800)
committerJagan Teki <jteki@openedev.com>
Mon, 29 Jun 2015 19:10:10 +0000 (00:40 +0530)
Atmel DataFlash chips have commands different from common spi
flash commands.
Atmel DataFlash also have special page-size.
This driver add support for accessing Atmel DataFlash.
It is based on the Driver Model.
Example:
=> sf probe 1:0
SPI DataFlash: Detected AT45DB021B with page size 264 Bytes, erase size 264 Bytes, total 264 KiB, revision d
=> sf erase 0 42000
SF: 270336 bytes @ 0x0 Erased: OK
=> mw.l 82000000 45444342 20000
=> sf write 82000000 0 42000
SF: 270336 bytes @ 0x0 Written: OK
=> sf read 83000000 0 42000
SF: 270336 bytes @ 0x0 Read: OK
=> cmp.b 82000000 83000000 42000
Total of 270336 byte(s) were the same

Signed-off-by: Haikun Wang <haikun.wang@freescale.com>
Tested-by: Haikun Wang <haikun.wang@freescale.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Chakra Divi <cdivi@openedev.com>
Reviewed-by: Jagan Teki <jteki@openedev.com>
drivers/mtd/spi/Makefile
drivers/mtd/spi/sf_dataflash.c [new file with mode: 0644]

index c61b784e178cf2488ee28ce0857fbe8a478827fb..87f20bc3ad46ba8a01fae3ab7c53c515cbc94704 100644 (file)
@@ -15,6 +15,7 @@ endif
 #ifndef CONFIG_DM_SPI
 obj-$(CONFIG_SPI_FLASH) += sf_probe.o
 #endif
+obj-$(CONFIG_SF_DATAFLASH) += sf_dataflash.o
 obj-$(CONFIG_CMD_SF) += sf.o
 obj-$(CONFIG_SPI_FLASH) += sf_ops.o sf_params.o
 obj-$(CONFIG_SPI_FLASH_SANDBOX) += sandbox.o
diff --git a/drivers/mtd/spi/sf_dataflash.c b/drivers/mtd/spi/sf_dataflash.c
new file mode 100644 (file)
index 0000000..d287db8
--- /dev/null
@@ -0,0 +1,711 @@
+/*
+ *
+ * Atmel DataFlash probing
+ *
+ * Copyright (C) 2004-2009, 2015 Freescale Semiconductor, Inc.
+ * Haikun Wang (haikun.wang@freescale.com)
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+*/
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <fdtdec.h>
+#include <spi.h>
+#include <spi_flash.h>
+#include <div64.h>
+#include <linux/err.h>
+#include <linux/math64.h>
+
+#include "sf_internal.h"
+
+/*
+ * DataFlash is a kind of SPI flash.  Most AT45 chips have two buffers in
+ * each chip, which may be used for double buffered I/O; but this driver
+ * doesn't (yet) use these for any kind of i/o overlap or prefetching.
+ *
+ * Sometimes DataFlash is packaged in MMC-format cards, although the
+ * MMC stack can't (yet?) distinguish between MMC and DataFlash
+ * protocols during enumeration.
+ */
+
+/* reads can bypass the buffers */
+#define OP_READ_CONTINUOUS     0xE8
+#define OP_READ_PAGE           0xD2
+
+/* group B requests can run even while status reports "busy" */
+#define OP_READ_STATUS         0xD7    /* group B */
+
+/* move data between host and buffer */
+#define OP_READ_BUFFER1                0xD4    /* group B */
+#define OP_READ_BUFFER2                0xD6    /* group B */
+#define OP_WRITE_BUFFER1       0x84    /* group B */
+#define OP_WRITE_BUFFER2       0x87    /* group B */
+
+/* erasing flash */
+#define OP_ERASE_PAGE          0x81
+#define OP_ERASE_BLOCK         0x50
+
+/* move data between buffer and flash */
+#define OP_TRANSFER_BUF1       0x53
+#define OP_TRANSFER_BUF2       0x55
+#define OP_MREAD_BUFFER1       0xD4
+#define OP_MREAD_BUFFER2       0xD6
+#define OP_MWERASE_BUFFER1     0x83
+#define OP_MWERASE_BUFFER2     0x86
+#define OP_MWRITE_BUFFER1      0x88    /* sector must be pre-erased */
+#define OP_MWRITE_BUFFER2      0x89    /* sector must be pre-erased */
+
+/* write to buffer, then write-erase to flash */
+#define OP_PROGRAM_VIA_BUF1    0x82
+#define OP_PROGRAM_VIA_BUF2    0x85
+
+/* compare buffer to flash */
+#define OP_COMPARE_BUF1                0x60
+#define OP_COMPARE_BUF2                0x61
+
+/* read flash to buffer, then write-erase to flash */
+#define OP_REWRITE_VIA_BUF1    0x58
+#define OP_REWRITE_VIA_BUF2    0x59
+
+/*
+ * newer chips report JEDEC manufacturer and device IDs; chip
+ * serial number and OTP bits; and per-sector writeprotect.
+ */
+#define OP_READ_ID             0x9F
+#define OP_READ_SECURITY       0x77
+#define OP_WRITE_SECURITY_REVC 0x9A
+#define OP_WRITE_SECURITY      0x9B    /* revision D */
+
+
+struct dataflash {
+       uint8_t                 command[16];
+       unsigned short          page_offset;    /* offset in flash address */
+};
+
+/*
+ * Return the status of the DataFlash device.
+ */
+static inline int dataflash_status(struct spi_slave *spi)
+{
+       int ret;
+       u8 status;
+       /*
+        * NOTE:  at45db321c over 25 MHz wants to write
+        * a dummy byte after the opcode...
+        */
+       ret = spi_flash_cmd(spi, OP_READ_STATUS, &status, 1);
+       return ret ? -EIO : status;
+}
+
+/*
+ * Poll the DataFlash device until it is READY.
+ * This usually takes 5-20 msec or so; more for sector erase.
+ * ready: return > 0
+ */
+static int dataflash_waitready(struct spi_slave *spi)
+{
+       int status;
+       int timeout = 2 * CONFIG_SYS_HZ;
+       int timebase;
+
+       timebase = get_timer(0);
+       do {
+               status = dataflash_status(spi);
+               if (status < 0)
+                       status = 0;
+
+               if (status & (1 << 7))  /* RDY/nBSY */
+                       return status;
+
+               mdelay(3);
+       } while (get_timer(timebase) < timeout);
+
+       return -ETIME;
+}
+
+/*
+ * Erase pages of flash.
+ */
+static int spi_dataflash_erase(struct udevice *dev, u32 offset, size_t len)
+{
+       struct dataflash        *dataflash;
+       struct spi_flash        *spi_flash;
+       struct spi_slave        *spi;
+       unsigned                blocksize;
+       uint8_t                 *command;
+       uint32_t                rem;
+       int                     status;
+
+       dataflash = dev_get_priv(dev);
+       spi_flash = dev_get_uclass_priv(dev);
+       spi = spi_flash->spi;
+
+       blocksize = spi_flash->page_size << 3;
+
+       memset(dataflash->command, 0 , sizeof(dataflash->command));
+       command = dataflash->command;
+
+       debug("%s: erase addr=0x%x len 0x%x\n", dev->name, offset, len);
+
+       div_u64_rem(len, spi_flash->page_size, &rem);
+       if (rem)
+               return -EINVAL;
+       div_u64_rem(offset, spi_flash->page_size, &rem);
+       if (rem)
+               return -EINVAL;
+
+       status = spi_claim_bus(spi);
+       if (status) {
+               debug("SPI DATAFLASH: unable to claim SPI bus\n");
+               return status;
+       }
+
+       while (len > 0) {
+               unsigned int    pageaddr;
+               int             do_block;
+               /*
+                * Calculate flash page address; use block erase (for speed) if
+                * we're at a block boundary and need to erase the whole block.
+                */
+               pageaddr = div_u64(offset, spi_flash->page_size);
+               do_block = (pageaddr & 0x7) == 0 && len >= blocksize;
+               pageaddr = pageaddr << dataflash->page_offset;
+
+               command[0] = do_block ? OP_ERASE_BLOCK : OP_ERASE_PAGE;
+               command[1] = (uint8_t)(pageaddr >> 16);
+               command[2] = (uint8_t)(pageaddr >> 8);
+               command[3] = 0;
+
+               debug("%s ERASE %s: (%x) %x %x %x [%d]\n",
+                     dev->name, do_block ? "block" : "page",
+                     command[0], command[1], command[2], command[3],
+                     pageaddr);
+
+               status = spi_flash_cmd_write(spi, command, 4, NULL, 0);
+               if (status < 0) {
+                       debug("%s: erase send command error!\n", dev->name);
+                       return -EIO;
+               }
+
+               status = dataflash_waitready(spi);
+               if (status < 0) {
+                       debug("%s: erase waitready error!\n", dev->name);
+                       return status;
+               }
+
+               if (do_block) {
+                       offset += blocksize;
+                       len -= blocksize;
+               } else {
+                       offset += spi_flash->page_size;
+                       len -= spi_flash->page_size;
+               }
+       }
+
+       spi_release_bus(spi);
+
+       return 0;
+}
+
+/*
+ * Read from the DataFlash device.
+ *   offset : Start offset in flash device
+ *   len    : Amount to read
+ *   buf    : Buffer containing the data
+ */
+static int spi_dataflash_read(struct udevice *dev, u32 offset, size_t len,
+                             void *buf)
+{
+       struct dataflash        *dataflash;
+       struct spi_flash        *spi_flash;
+       struct spi_slave        *spi;
+       unsigned int            addr;
+       uint8_t                 *command;
+       int                     status;
+
+       dataflash = dev_get_priv(dev);
+       spi_flash = dev_get_uclass_priv(dev);
+       spi = spi_flash->spi;
+
+       memset(dataflash->command, 0 , sizeof(dataflash->command));
+       command = dataflash->command;
+
+       debug("%s: erase addr=0x%x len 0x%x\n", dev->name, offset, len);
+       debug("READ: (%x) %x %x %x\n",
+             command[0], command[1], command[2], command[3]);
+
+       /* Calculate flash page/byte address */
+       addr = (((unsigned)offset / spi_flash->page_size)
+              << dataflash->page_offset)
+              + ((unsigned)offset % spi_flash->page_size);
+
+       status = spi_claim_bus(spi);
+       if (status) {
+               debug("SPI DATAFLASH: unable to claim SPI bus\n");
+               return status;
+       }
+
+       /*
+        * Continuous read, max clock = f(car) which may be less than
+        * the peak rate available.  Some chips support commands with
+        * fewer "don't care" bytes.  Both buffers stay unchanged.
+        */
+       command[0] = OP_READ_CONTINUOUS;
+       command[1] = (uint8_t)(addr >> 16);
+       command[2] = (uint8_t)(addr >> 8);
+       command[3] = (uint8_t)(addr >> 0);
+
+       /* plus 4 "don't care" bytes, command len: 4 + 4 "don't care" bytes */
+       status = spi_flash_cmd_read(spi, command, 8, buf, len);
+
+       spi_release_bus(spi);
+
+       return status;
+}
+
+/*
+ * Write to the DataFlash device.
+ *   offset     : Start offset in flash device
+ *   len    : Amount to write
+ *   buf    : Buffer containing the data
+ */
+int spi_dataflash_write(struct udevice *dev, u32 offset, size_t len,
+                       const void *buf)
+{
+       struct dataflash        *dataflash;
+       struct spi_flash        *spi_flash;
+       struct spi_slave        *spi;
+       uint8_t                 *command;
+       unsigned int            pageaddr, addr, to, writelen;
+       size_t                  remaining = len;
+       u_char                  *writebuf = (u_char *)buf;
+       int                     status = -EINVAL;
+
+       dataflash = dev_get_priv(dev);
+       spi_flash = dev_get_uclass_priv(dev);
+       spi = spi_flash->spi;
+
+       memset(dataflash->command, 0 , sizeof(dataflash->command));
+       command = dataflash->command;
+
+       debug("%s: write 0x%x..0x%x\n", dev->name, offset, (offset + len));
+
+       pageaddr = ((unsigned)offset / spi_flash->page_size);
+       to = ((unsigned)offset % spi_flash->page_size);
+       if (to + len > spi_flash->page_size)
+               writelen = spi_flash->page_size - to;
+       else
+               writelen = len;
+
+       status = spi_claim_bus(spi);
+       if (status) {
+               debug("SPI DATAFLASH: unable to claim SPI bus\n");
+               return status;
+       }
+
+       while (remaining > 0) {
+               debug("write @ %d:%d len=%d\n", pageaddr, to, writelen);
+
+               /*
+                * REVISIT:
+                * (a) each page in a sector must be rewritten at least
+                *     once every 10K sibling erase/program operations.
+                * (b) for pages that are already erased, we could
+                *     use WRITE+MWRITE not PROGRAM for ~30% speedup.
+                * (c) WRITE to buffer could be done while waiting for
+                *     a previous MWRITE/MWERASE to complete ...
+                * (d) error handling here seems to be mostly missing.
+                *
+                * Two persistent bits per page, plus a per-sector counter,
+                * could support (a) and (b) ... we might consider using
+                * the second half of sector zero, which is just one block,
+                * to track that state.  (On AT91, that sector should also
+                * support boot-from-DataFlash.)
+                */
+
+               addr = pageaddr << dataflash->page_offset;
+
+               /* (1) Maybe transfer partial page to Buffer1 */
+               if (writelen != spi_flash->page_size) {
+                       command[0] = OP_TRANSFER_BUF1;
+                       command[1] = (addr & 0x00FF0000) >> 16;
+                       command[2] = (addr & 0x0000FF00) >> 8;
+                       command[3] = 0;
+
+                       debug("TRANSFER: (%x) %x %x %x\n",
+                             command[0], command[1], command[2], command[3]);
+
+                       status = spi_flash_cmd_write(spi, command, 4, NULL, 0);
+                       if (status < 0) {
+                               debug("%s: write(<pagesize) command error!\n",
+                                     dev->name);
+                               return -EIO;
+                       }
+
+                       status = dataflash_waitready(spi);
+                       if (status < 0) {
+                               debug("%s: write(<pagesize) waitready error!\n",
+                                     dev->name);
+                               return status;
+                       }
+               }
+
+               /* (2) Program full page via Buffer1 */
+               addr += to;
+               command[0] = OP_PROGRAM_VIA_BUF1;
+               command[1] = (addr & 0x00FF0000) >> 16;
+               command[2] = (addr & 0x0000FF00) >> 8;
+               command[3] = (addr & 0x000000FF);
+
+               debug("PROGRAM: (%x) %x %x %x\n",
+                     command[0], command[1], command[2], command[3]);
+
+               status = spi_flash_cmd_write(spi, command,
+                                            4, writebuf, writelen);
+               if (status < 0) {
+                       debug("%s: write send command error!\n", dev->name);
+                       return -EIO;
+               }
+
+               status = dataflash_waitready(spi);
+               if (status < 0) {
+                       debug("%s: write waitready error!\n", dev->name);
+                       return status;
+               }
+
+#ifdef CONFIG_SPI_DATAFLASH_WRITE_VERIFY
+               /* (3) Compare to Buffer1 */
+               addr = pageaddr << dataflash->page_offset;
+               command[0] = OP_COMPARE_BUF1;
+               command[1] = (addr & 0x00FF0000) >> 16;
+               command[2] = (addr & 0x0000FF00) >> 8;
+               command[3] = 0;
+
+               debug("COMPARE: (%x) %x %x %x\n",
+                     command[0], command[1], command[2], command[3]);
+
+               status = spi_flash_cmd_write(spi, command,
+                                            4, writebuf, writelen);
+               if (status < 0) {
+                       debug("%s: write(compare) send command error!\n",
+                             dev->name);
+                       return -EIO;
+               }
+
+               status = dataflash_waitready(spi);
+
+               /* Check result of the compare operation */
+               if (status & (1 << 6)) {
+                       printf("SPI DataFlash: write compare page %u, err %d\n",
+                              pageaddr, status);
+                       remaining = 0;
+                       status = -EIO;
+                       break;
+               } else {
+                       status = 0;
+               }
+
+#endif /* CONFIG_SPI_DATAFLASH_WRITE_VERIFY */
+               remaining = remaining - writelen;
+               pageaddr++;
+               to = 0;
+               writebuf += writelen;
+
+               if (remaining > spi_flash->page_size)
+                       writelen = spi_flash->page_size;
+               else
+                       writelen = remaining;
+       }
+
+       spi_release_bus(spi);
+
+       return 0;
+}
+
+static int add_dataflash(struct udevice *dev, char *name, int nr_pages,
+                            int pagesize, int pageoffset, char revision)
+{
+       struct spi_flash *spi_flash;
+       struct dataflash *dataflash;
+
+       dataflash = dev_get_priv(dev);
+       spi_flash = dev_get_uclass_priv(dev);
+
+       dataflash->page_offset = pageoffset;
+
+       spi_flash->name = name;
+       spi_flash->page_size = pagesize;
+       spi_flash->size = nr_pages * pagesize;
+       spi_flash->erase_size = pagesize;
+
+#ifndef CONFIG_SPL_BUILD
+       printf("SPI DataFlash: Detected %s with page size ", spi_flash->name);
+       print_size(spi_flash->page_size, ", erase size ");
+       print_size(spi_flash->erase_size, ", total ");
+       print_size(spi_flash->size, "");
+       printf(", revision %c", revision);
+       puts("\n");
+#endif
+
+       return 0;
+}
+
+struct flash_info {
+       char            *name;
+
+       /*
+        * JEDEC id has a high byte of zero plus three data bytes:
+        * the manufacturer id, then a two byte device id.
+        */
+       uint32_t        jedec_id;
+
+       /* The size listed here is what works with OP_ERASE_PAGE. */
+       unsigned        nr_pages;
+       uint16_t        pagesize;
+       uint16_t        pageoffset;
+
+       uint16_t        flags;
+#define SUP_POW2PS     0x0002          /* supports 2^N byte pages */
+#define IS_POW2PS      0x0001          /* uses 2^N byte pages */
+};
+
+static struct flash_info dataflash_data[] = {
+       /*
+        * NOTE:  chips with SUP_POW2PS (rev D and up) need two entries,
+        * one with IS_POW2PS and the other without.  The entry with the
+        * non-2^N byte page size can't name exact chip revisions without
+        * losing backwards compatibility for cmdlinepart.
+        *
+        * Those two entries have different name spelling format in order to
+        * show their difference obviously.
+        * The upper case refer to the chip isn't in normal 2^N bytes page-size
+        * mode.
+        * The lower case refer to the chip is in normal 2^N bytes page-size
+        * mode.
+        *
+        * These newer chips also support 128-byte security registers (with
+        * 64 bytes one-time-programmable) and software write-protection.
+        */
+       { "AT45DB011B",  0x1f2200, 512, 264, 9, SUP_POW2PS},
+       { "at45db011d",  0x1f2200, 512, 256, 8, SUP_POW2PS | IS_POW2PS},
+
+       { "AT45DB021B",  0x1f2300, 1024, 264, 9, SUP_POW2PS},
+       { "at45db021d",  0x1f2300, 1024, 256, 8, SUP_POW2PS | IS_POW2PS},
+
+       { "AT45DB041x",  0x1f2400, 2048, 264, 9, SUP_POW2PS},
+       { "at45db041d",  0x1f2400, 2048, 256, 8, SUP_POW2PS | IS_POW2PS},
+
+       { "AT45DB081B",  0x1f2500, 4096, 264, 9, SUP_POW2PS},
+       { "at45db081d",  0x1f2500, 4096, 256, 8, SUP_POW2PS | IS_POW2PS},
+
+       { "AT45DB161x",  0x1f2600, 4096, 528, 10, SUP_POW2PS},
+       { "at45db161d",  0x1f2600, 4096, 512, 9, SUP_POW2PS | IS_POW2PS},
+
+       { "AT45DB321x",  0x1f2700, 8192, 528, 10, 0},           /* rev C */
+
+       { "AT45DB321x",  0x1f2701, 8192, 528, 10, SUP_POW2PS},
+       { "at45db321d",  0x1f2701, 8192, 512, 9, SUP_POW2PS | IS_POW2PS},
+
+       { "AT45DB642x",  0x1f2800, 8192, 1056, 11, SUP_POW2PS},
+       { "at45db642d",  0x1f2800, 8192, 1024, 10, SUP_POW2PS | IS_POW2PS},
+};
+
+static struct flash_info *jedec_probe(struct spi_slave *spi, u8 *id)
+{
+       int                     tmp;
+       uint32_t                jedec;
+       struct flash_info       *info;
+       int status;
+
+       /*
+        * JEDEC also defines an optional "extended device information"
+        * string for after vendor-specific data, after the three bytes
+        * we use here.  Supporting some chips might require using it.
+        *
+        * If the vendor ID isn't Atmel's (0x1f), assume this call failed.
+        * That's not an error; only rev C and newer chips handle it, and
+        * only Atmel sells these chips.
+        */
+       if (id[0] != 0x1f)
+               return NULL;
+
+       jedec = id[0];
+       jedec = jedec << 8;
+       jedec |= id[1];
+       jedec = jedec << 8;
+       jedec |= id[2];
+
+       for (tmp = 0, info = dataflash_data;
+                       tmp < ARRAY_SIZE(dataflash_data);
+                       tmp++, info++) {
+               if (info->jedec_id == jedec) {
+                       if (info->flags & SUP_POW2PS) {
+                               status = dataflash_status(spi);
+                               if (status < 0) {
+                                       debug("SPI DataFlash: status error %d\n",
+                                             status);
+                                       return NULL;
+                               }
+                               if (status & 0x1) {
+                                       if (info->flags & IS_POW2PS)
+                                               return info;
+                               } else {
+                                       if (!(info->flags & IS_POW2PS))
+                                               return info;
+                               }
+                       } else {
+                               return info;
+                       }
+               }
+       }
+
+       /*
+        * Treat other chips as errors ... we won't know the right page
+        * size (it might be binary) even when we can tell which density
+        * class is involved (legacy chip id scheme).
+        */
+       printf("SPI DataFlash: Unsupported flash IDs: ");
+       printf("manuf %02x, jedec %04x, ext_jedec %04x\n",
+              id[0], jedec, id[3] << 8 | id[4]);
+       return NULL;
+}
+
+/*
+ * Detect and initialize DataFlash device, using JEDEC IDs on newer chips
+ * or else the ID code embedded in the status bits:
+ *
+ *   Device      Density         ID code          #Pages PageSize  Offset
+ *   AT45DB011B  1Mbit   (128K)  xx0011xx (0x0c)    512    264      9
+ *   AT45DB021B  2Mbit   (256K)  xx0101xx (0x14)   1024    264      9
+ *   AT45DB041B  4Mbit   (512K)  xx0111xx (0x1c)   2048    264      9
+ *   AT45DB081B  8Mbit   (1M)    xx1001xx (0x24)   4096    264      9
+ *   AT45DB0161B 16Mbit  (2M)    xx1011xx (0x2c)   4096    528     10
+ *   AT45DB0321B 32Mbit  (4M)    xx1101xx (0x34)   8192    528     10
+ *   AT45DB0642  64Mbit  (8M)    xx111xxx (0x3c)   8192   1056     11
+ *   AT45DB1282  128Mbit (16M)   xx0100xx (0x10)  16384   1056     11
+ */
+static int spi_dataflash_probe(struct udevice *dev)
+{
+       struct spi_slave *spi = dev_get_parentdata(dev);
+       struct spi_flash *spi_flash;
+       struct flash_info *info;
+       u8 idcode[5];
+       int ret, status = 0;
+
+       spi_flash = dev_get_uclass_priv(dev);
+       spi_flash->dev = dev;
+
+       ret = spi_claim_bus(spi);
+       if (ret)
+               return ret;
+
+       ret = spi_flash_cmd(spi, CMD_READ_ID, idcode, sizeof(idcode));
+       if (ret) {
+               printf("SPI DataFlash: Failed to get idcodes\n");
+               goto err_read_cmd;
+       }
+
+       /*
+        * Try to detect dataflash by JEDEC ID.
+        * If it succeeds we know we have either a C or D part.
+        * D will support power of 2 pagesize option.
+        * Both support the security register, though with different
+        * write procedures.
+        */
+       info = jedec_probe(spi, idcode);
+       if (info != NULL)
+               add_dataflash(dev, info->name, info->nr_pages,
+                             info->pagesize, info->pageoffset,
+                             (info->flags & SUP_POW2PS) ? 'd' : 'c');
+       else {
+               /*
+               * Older chips support only legacy commands, identifing
+               * capacity using bits in the status byte.
+               */
+               status = dataflash_status(spi);
+               if (status <= 0 || status == 0xff) {
+                       printf("SPI DataFlash: read status error %d\n", status);
+                       if (status == 0 || status == 0xff)
+                               status = -ENODEV;
+                       goto err_read_cmd;
+               }
+               /*
+               * if there's a device there, assume it's dataflash.
+               * board setup should have set spi->max_speed_max to
+               * match f(car) for continuous reads, mode 0 or 3.
+               */
+               switch (status & 0x3c) {
+               case 0x0c:      /* 0 0 1 1 x x */
+                       status = add_dataflash(dev, "AT45DB011B",
+                                              512, 264, 9, 0);
+                       break;
+               case 0x14:      /* 0 1 0 1 x x */
+                       status = add_dataflash(dev, "AT45DB021B",
+                                              1024, 264, 9, 0);
+                       break;
+               case 0x1c:      /* 0 1 1 1 x x */
+                       status = add_dataflash(dev, "AT45DB041x",
+                                              2048, 264, 9, 0);
+                       break;
+               case 0x24:      /* 1 0 0 1 x x */
+                       status = add_dataflash(dev, "AT45DB081B",
+                                              4096, 264, 9, 0);
+                       break;
+               case 0x2c:      /* 1 0 1 1 x x */
+                       status = add_dataflash(dev, "AT45DB161x",
+                                              4096, 528, 10, 0);
+                       break;
+               case 0x34:      /* 1 1 0 1 x x */
+                       status = add_dataflash(dev, "AT45DB321x",
+                                              8192, 528, 10, 0);
+                       break;
+               case 0x38:      /* 1 1 1 x x x */
+               case 0x3c:
+                       status = add_dataflash(dev, "AT45DB642x",
+                                              8192, 1056, 11, 0);
+                       break;
+               /* obsolete AT45DB1282 not (yet?) supported */
+               default:
+                       dev_info(&spi->dev, "unsupported device (%x)\n",
+                                status & 0x3c);
+                       status = -ENODEV;
+                       goto err_read_cmd;
+               }
+       }
+
+       /* Assign spi data */
+       spi_flash->spi = spi;
+       spi_flash->memory_map = spi->memory_map;
+       spi_flash->dual_flash = spi->option;
+
+       spi_release_bus(spi);
+
+       return 0;
+
+err_read_cmd:
+       spi_release_bus(spi);
+
+       return status;
+}
+
+static const struct dm_spi_flash_ops spi_dataflash_ops = {
+       .read = spi_dataflash_read,
+       .write = spi_dataflash_write,
+       .erase = spi_dataflash_erase,
+};
+
+static const struct udevice_id spi_dataflash_ids[] = {
+       { .compatible = "atmel,at45", },
+       { .compatible = "atmel,dataflash", },
+       { }
+};
+
+U_BOOT_DRIVER(spi_dataflash) = {
+       .name           = "spi_dataflash",
+       .id             = UCLASS_SPI_FLASH,
+       .of_match       = spi_dataflash_ids,
+       .probe          = spi_dataflash_probe,
+       .priv_auto_alloc_size = sizeof(struct dataflash),
+       .ops            = &spi_dataflash_ops,
+};