sf: Add dual memories support - DUAL_STACKED
authorJagannadha Sutradharudu Teki <jaganna@xilinx.com>
Sun, 12 Jan 2014 16:10:11 +0000 (21:40 +0530)
committerJagannadha Sutradharudu Teki <jaganna@xilinx.com>
Sun, 12 Jan 2014 16:10:11 +0000 (21:40 +0530)
This patch added support for accessing dual memories in
stacked connection with single chipselect line from controller.

For more info - see doc/SPI/README.dual-flash

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
doc/SPI/README.dual-flash [new file with mode: 0644]
drivers/mtd/spi/sf.c
drivers/mtd/spi/sf_ops.c
drivers/mtd/spi/sf_probe.c
include/spi.h
include/spi_flash.h

diff --git a/doc/SPI/README.dual-flash b/doc/SPI/README.dual-flash
new file mode 100644 (file)
index 0000000..ba0aa26
--- /dev/null
@@ -0,0 +1,65 @@
+SPI/QSPI Dual flash connection modes:
+=====================================
+
+This describes how SPI/QSPI flash memories are connected to a given
+controller in a single chip select line.
+
+Current spi_flash framework supports, single flash memory connected
+to a given controller with single chip select line, but there are some
+hw logics(ex: xilinx zynq qspi) that describes two/dual memories are
+connected with a single chip select line from a controller.
+
+"dual_flash" from include/spi.h describes these types of connection mode
+
+Possible connections:
+--------------------
+SF_SINGLE_FLASH:
+       - single spi flash memory connected with single chip select line.
+
+  +------------+             CS         +---------------+
+  |            |----------------------->|               |
+  | Controller |         I0[3:0]        | Flash memory  |
+  | SPI/QSPI   |<======================>| (SPI/QSPI)    |
+  |            |           CLK          |               |
+  |            |----------------------->|               |
+  +------------+                        +---------------+
+
+SF_DUAL_STACKED_FLASH:
+       - dual spi/qspi flash memories are connected with a single chipselect
+         line and these two memories are operating stacked fasion with shared buses.
+       - xilinx zynq qspi controller has implemented this feature [1]
+
+  +------------+        CS             +---------------+
+  |            |---------------------->|               |
+  |            |              I0[3:0]  | Upper Flash   |
+  |            |            +=========>| memory        |
+  |            |            |     CLK  | (SPI/QSPI)    |
+  |            |            |    +---->|               |
+  | Controller |        CS  |    |     +---------------+
+  | SPI/QSPI   |------------|----|---->|               |
+  |            |    I0[3:0] |    |     | Lower Flash   |
+  |            |<===========+====|====>| memory        |
+  |            |          CLK    |     | (SPI/QSPI)    |
+  |            |-----------------+---->|               |
+  +------------+                       +---------------+
+
+       - two memory flash devices should has same hw part attributes (like size,
+         vendor..etc)
+       - Configurations:
+               on LQSPI_CFG register, Enable TWO_MEM[BIT:30] on LQSPI_CFG
+               Enable U_PAGE[BIT:28] if U_PAGE flag set - upper memory
+               Disable U_PAGE[BIT:28] if U_PAGE flag unset - lower memory
+       - Operation:
+               accessing memories serially like one after another.
+               by default, if U_PAGE is unset lower memory should accessible,
+               once user wants to access upper memory need to set U_PAGE.
+
+Note: Technically there is only one CS line from the controller, but
+zynq qspi controller has an internal hw logic to enable additional CS
+when controller is configured for dual memories.
+
+[1] http://www.xilinx.com/support/documentation/user_guides/ug585-Zynq-7000-TRM.pdf
+
+--
+Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
+05-01-2014.
index d5e175ca0000f571ed3cfa290cbd12653cd10f76..c780a81c599076056cb10c1edb2cd582c29576fc 100644 (file)
@@ -18,6 +18,9 @@ static int spi_flash_read_write(struct spi_slave *spi,
        unsigned long flags = SPI_XFER_BEGIN;
        int ret;
 
+       if (spi->flags & SPI_XFER_U_PAGE)
+               flags |= SPI_XFER_U_PAGE;
+
        if (data_len == 0)
                flags |= SPI_XFER_END;
 
index 7ae958211e88e3f02e714ae4b215a4621204a53d..e877858a918543501b8d6d7628fe303c532a5913 100644 (file)
@@ -131,10 +131,28 @@ static int spi_flash_bank(struct spi_flash *flash, u32 offset)
 }
 #endif
 
+static void spi_flash_dual_flash(struct spi_flash *flash, u32 *addr)
+{
+       switch (flash->dual_flash) {
+       case SF_DUAL_STACKED_FLASH:
+               if (*addr >= (flash->size >> 1)) {
+                       *addr -= flash->size >> 1;
+                       flash->spi->flags |= SPI_XFER_U_PAGE;
+               } else {
+                       flash->spi->flags &= ~SPI_XFER_U_PAGE;
+               }
+               break;
+       default:
+               debug("SF: Unsupported dual_flash=%d\n", flash->dual_flash);
+               break;
+       }
+}
+
 int spi_flash_cmd_wait_ready(struct spi_flash *flash, unsigned long timeout)
 {
        struct spi_slave *spi = flash->spi;
        unsigned long timebase;
+       unsigned long flags = SPI_XFER_BEGIN;
        int ret;
        u8 status;
        u8 check_status = 0x0;
@@ -146,7 +164,10 @@ int spi_flash_cmd_wait_ready(struct spi_flash *flash, unsigned long timeout)
                check_status = poll_bit;
        }
 
-       ret = spi_xfer(spi, 8, &cmd, NULL, SPI_XFER_BEGIN);
+       if (spi->flags & SPI_XFER_U_PAGE)
+               flags |= SPI_XFER_U_PAGE;
+
+       ret = spi_xfer(spi, 8, &cmd, NULL, flags);
        if (ret) {
                debug("SF: fail to read %s status register\n",
                      cmd == CMD_READ_STATUS ? "read" : "flag");
@@ -219,7 +240,7 @@ int spi_flash_write_common(struct spi_flash *flash, const u8 *cmd,
 
 int spi_flash_cmd_erase_ops(struct spi_flash *flash, u32 offset, size_t len)
 {
-       u32 erase_size;
+       u32 erase_size, erase_addr;
        u8 cmd[SPI_FLASH_CMD_LEN];
        int ret = -1;
 
@@ -231,15 +252,20 @@ int spi_flash_cmd_erase_ops(struct spi_flash *flash, u32 offset, size_t len)
 
        cmd[0] = flash->erase_cmd;
        while (len) {
+               erase_addr = offset;
+
+               if (flash->dual_flash > SF_SINGLE_FLASH)
+                       spi_flash_dual_flash(flash, &erase_addr);
+
 #ifdef CONFIG_SPI_FLASH_BAR
-               ret = spi_flash_bank(flash, offset);
+               ret = spi_flash_bank(flash, erase_addr);
                if (ret < 0)
                        return ret;
 #endif
-               spi_flash_addr(offset, cmd);
+               spi_flash_addr(erase_addr, cmd);
 
                debug("SF: erase %2x %2x %2x %2x (%x)\n", cmd[0], cmd[1],
-                     cmd[2], cmd[3], offset);
+                     cmd[2], cmd[3], erase_addr);
 
                ret = spi_flash_write_common(flash, cmd, sizeof(cmd), NULL, 0);
                if (ret < 0) {
@@ -258,6 +284,7 @@ int spi_flash_cmd_write_ops(struct spi_flash *flash, u32 offset,
                size_t len, const void *buf)
 {
        unsigned long byte_addr, page_size;
+       u32 write_addr;
        size_t chunk_len, actual;
        u8 cmd[SPI_FLASH_CMD_LEN];
        int ret = -1;
@@ -266,8 +293,13 @@ int spi_flash_cmd_write_ops(struct spi_flash *flash, u32 offset,
 
        cmd[0] = flash->write_cmd;
        for (actual = 0; actual < len; actual += chunk_len) {
+               write_addr = offset;
+
+               if (flash->dual_flash > SF_SINGLE_FLASH)
+                       spi_flash_dual_flash(flash, &write_addr);
+
 #ifdef CONFIG_SPI_FLASH_BAR
-               ret = spi_flash_bank(flash, offset);
+               ret = spi_flash_bank(flash, write_addr);
                if (ret < 0)
                        return ret;
 #endif
@@ -277,7 +309,7 @@ int spi_flash_cmd_write_ops(struct spi_flash *flash, u32 offset,
                if (flash->spi->max_write_size)
                        chunk_len = min(chunk_len, flash->spi->max_write_size);
 
-               spi_flash_addr(offset, cmd);
+               spi_flash_addr(write_addr, cmd);
 
                debug("SF: 0x%p => cmd = { 0x%02x 0x%02x%02x%02x } chunk_len = %zu\n",
                      buf + actual, cmd[0], cmd[1], cmd[2], cmd[3], chunk_len);
@@ -322,7 +354,7 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
                size_t len, void *data)
 {
        u8 *cmd, cmdsz;
-       u32 remain_len, read_len;
+       u32 remain_len, read_len, read_addr;
        int bank_sel = 0;
        int ret = -1;
 
@@ -346,8 +378,13 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
 
        cmd[0] = flash->read_cmd;
        while (len) {
+               read_addr = offset;
+
+               if (flash->dual_flash > SF_SINGLE_FLASH)
+                       spi_flash_dual_flash(flash, &read_addr);
+
 #ifdef CONFIG_SPI_FLASH_BAR
-               bank_sel = spi_flash_bank(flash, offset);
+               bank_sel = spi_flash_bank(flash, read_addr);
                if (bank_sel < 0)
                        return ret;
 #endif
@@ -357,7 +394,7 @@ int spi_flash_cmd_read_ops(struct spi_flash *flash, u32 offset,
                else
                        read_len = remain_len;
 
-               spi_flash_addr(offset, cmd);
+               spi_flash_addr(read_addr, cmd);
 
                ret = spi_flash_read_common(flash, cmd, cmdsz, data, read_len);
                if (ret < 0) {
index ac42b60c82a33d22de83844e95277706727a86a8..b9e14c5a2bb1ac45a2ef3e9b0d4147cbff2a8302 100644 (file)
@@ -134,6 +134,7 @@ static struct spi_flash *spi_flash_validate_params(struct spi_slave *spi,
        flash->spi = spi;
        flash->name = params->name;
        flash->memory_map = spi->memory_map;
+       flash->dual_flash = flash->spi->option;
 
        /* Assign spi_flash ops */
        flash->write = spi_flash_cmd_write_ops;
@@ -148,6 +149,8 @@ static struct spi_flash *spi_flash_validate_params(struct spi_slave *spi,
        flash->page_size = (ext_jedec == 0x4d00) ? 512 : 256;
        flash->sector_size = params->sector_size;
        flash->size = flash->sector_size * params->nr_sectors;
+       if (flash->dual_flash & SF_DUAL_STACKED_FLASH)
+               flash->size <<= 1;
 
        /* Compute erase sector and command */
        if (params->flags & SECT_4K) {
@@ -324,7 +327,10 @@ static struct spi_flash *spi_flash_probe_slave(struct spi_slave *spi)
        puts("\n");
 #endif
 #ifndef CONFIG_SPI_FLASH_BAR
-       if (flash->size > SPI_FLASH_16MB_BOUN) {
+       if (((flash->dual_flash == SF_SINGLE_FLASH) &&
+            (flash->size > SPI_FLASH_16MB_BOUN)) ||
+            ((flash->dual_flash > SF_SINGLE_FLASH) &&
+            (flash->size > SPI_FLASH_16MB_BOUN << 1))) {
                puts("SF: Warning - Only lower 16MiB accessible,");
                puts(" Full access #define CONFIG_SPI_FLASH_BAR\n");
        }
index c8a9d87b5f9b0a2b9a9bcd126ffc48490830a725..d214d82923997ea86d5cc3975d0b7c5b8e6d2701 100644 (file)
@@ -30,6 +30,7 @@
 #define SPI_XFER_MMAP          0x08    /* Memory Mapped start */
 #define SPI_XFER_MMAP_END      0x10    /* Memory Mapped End */
 #define SPI_XFER_ONCE          (SPI_XFER_BEGIN | SPI_XFER_END)
+#define SPI_XFER_U_PAGE                (1 << 5)
 
 /* SPI TX operation modes */
 #define SPI_OPM_TX_QPP         1 << 0
@@ -44,6 +45,9 @@
                                SPI_OPM_RX_DIO | SPI_OPM_RX_QOF | \
                                SPI_OPM_RX_QIOF
 
+/* SPI bus connection options */
+#define SPI_CONN_DUAL_SHARED   1 << 0
+
 /* Header byte that marks the start of the message */
 #define SPI_PREAMBLE_END_BYTE  0xec
 
@@ -62,6 +66,8 @@
  * @max_write_size:    If non-zero, the maximum number of bytes which can
  *                     be written at once, excluding command bytes.
  * @memory_map:                Address of read-only SPI flash access.
+ * @option:            Varies SPI bus options - separate bus.
+ * @flags:             Indication of SPI flags.
  */
 struct spi_slave {
        unsigned int bus;
@@ -71,6 +77,8 @@ struct spi_slave {
        unsigned int wordlen;
        unsigned int max_write_size;
        void *memory_map;
+       u8 option;
+       u8 flags;
 };
 
 /**
index 213d6592be90605b08b68d88157e048f7707d418..36f1f033c0c20db78a38c0fe6443ef566190340e 100644 (file)
@@ -36,6 +36,12 @@ enum spi_read_cmds {
 #define RD_EXTN                ARRAY_SLOW | DUAL_OUTPUT_FAST | DUAL_IO_FAST
 #define RD_FULL                RD_EXTN | QUAD_OUTPUT_FAST | QUAD_IO_FAST
 
+/* Dual SPI flash memories */
+enum spi_dual_flash {
+       SF_SINGLE_FLASH = 0,
+       SF_DUAL_STACKED_FLASH = 1 << 0,
+};
+
 /**
  * struct spi_flash_params - SPI/QSPI flash device params structure
  *
@@ -64,6 +70,7 @@ extern const struct spi_flash_params spi_flash_params_table[];
  *
  * @spi:               SPI slave
  * @name:              Name of SPI flash
+ * @dual_flash:                Indicates dual flash memories - dual stacked
  * @size:              Total flash size
  * @page_size:         Write (page) size
  * @sector_size:       Sector size
@@ -88,6 +95,7 @@ extern const struct spi_flash_params spi_flash_params_table[];
 struct spi_flash {
        struct spi_slave *spi;
        const char *name;
+       u8 dual_flash;
 
        u32 size;
        u32 page_size;