[U-Boot] [RFC] [PATCH 1/4] Support for 'single frame' spi flash commands

[Can Aydin]

  Add a single-hit transaction to the spi flash framework.
  Useful for when the hardware makes it impossible to maintain CS
  state between disparate command and data calls by requiring a
  'frame length' (thus pre-determining how many clock cycles the
  CS will stay asserted).
  Such is the case with the Freescale eSPI controller.

Signed-off-by: Can Aydin<can.aydin at locatacorp.com>

---
  drivers/mtd/spi/spi_flash.c          |   38 +++++++++++++++++++++++++++++++--
  drivers/mtd/spi/spi_flash_internal.h |    9 ++++++++
  2 files changed, 44 insertions(+), 3 deletions(-)
  mode change 100644 =>  100755 drivers/mtd/spi/spi_flash.c
  mode change 100644 =>  100755 drivers/mtd/spi/spi_flash_internal.h

diff --git a/drivers/mtd/spi/spi_flash.c b/drivers/mtd/spi/spi_flash.c
old mode 100644
new mode 100755
index ea875dc..7646fc5
--- a/drivers/mtd/spi/spi_flash.c
+++ b/drivers/mtd/spi/spi_flash.c
@@ -70,12 +70,12 @@ int spi_flash_cmd_write(struct spi_slave *spi, const u8 *cmd, size_t cmd_len,

  	ret = spi_xfer(spi, cmd_len * 8, cmd, NULL, flags);
  	if (ret) {
-		debug("SF: Failed to send read command (%zu bytes): %d\n",
+		debug("SF: Failed to send write command (%zu bytes): %d\n",
  				cmd_len, ret);
  	} else if (data_len != 0) {
  		ret = spi_xfer(spi, data_len * 8, data, NULL, SPI_XFER_END);
  		if (ret)
-			debug("SF: Failed to read %zu bytes of data: %d\n",
+			debug("SF: Failed to write %zu bytes of data: %d\n",
  					data_len, ret);
  	}

@@ -96,6 +96,37 @@ int spi_flash_read_common(struct spi_flash *flash, const u8 *cmd,
  	return ret;
  }

+int spi_flash_cmd_rw_frame(struct spi_slave *spi, const u8 *cmd,
+		size_t cmd_len, void *data, size_t data_len)
+{
+	unsigned char *buffer;
+	int ret;
+
+	buffer = (unsigned char *)malloc(cmd_len + data_len);
+	if (!buffer) {
+		debug("SF: Failed to malloc memory.\n");
+		return 1;
+	}
+	if ( cmd_len&&  cmd )
+		memcpy(buffer, cmd, cmd_len);
+	if ( data_len&&  data )
+		memcpy(buffer+cmd_len, data, data_len);
+	ret = spi_xfer(spi, (cmd_len + data_len)*8, buffer, buffer,
+					SPI_XFER_BEGIN|SPI_XFER_END);
+	if (!ret) {
+		if ( cmd&&  cmd_len )
+			memcpy(cmd, buffer,cmd_len);
+		if ( data&&  data_len)
+			memcpy(data, buffer + cmd_len,data_len);
+	} else {
+		debug("SF: Transaction failed (command length: %zu bytes),"
+			" (data length: %zu bytes) : %d\n",
+		      cmd_len, data_len, ret);
+	}
+	free(buffer);
+	return ret;
+}
+
  struct spi_flash *spi_flash_probe(unsigned int bus, unsigned int cs,
  		unsigned int max_hz, unsigned int spi_mode)
  {
@@ -117,7 +148,8 @@ struct spi_flash *spi_flash_probe(unsigned int bus, unsigned int cs,
  	}

  	/* Read the ID codes */
-	ret = spi_flash_cmd(spi, CMD_READ_ID,&idcode, sizeof(idcode));
+	idcode[0] = CMD_READ_ID;
+	ret = spi_flash_cmd_rw_frame(spi,&(idcode[0]), 1, idcode, sizeof(idcode));
  	if (ret)
  		goto err_read_id;

diff --git a/drivers/mtd/spi/spi_flash_internal.h b/drivers/mtd/spi/spi_flash_internal.h
old mode 100644
new mode 100755
index 08546fb..0455dcc
--- a/drivers/mtd/spi/spi_flash_internal.h
+++ b/drivers/mtd/spi/spi_flash_internal.h
@@ -43,6 +43,15 @@ int spi_flash_cmd_write(struct spi_slave *spi, const u8 *cmd, size_t cmd_len,
  int spi_flash_read_common(struct spi_flash *flash, const u8 *cmd,
  		size_t cmd_len, void *data, size_t data_len);

+/*
+ * Similar to spi_flash_read_common() but command and data are combined and
+ * transferred in a single,pre-buffered frame. Useful for when the
+ * hardware makes it impossible to deterministically maintain CS state between
+ * disparate command and data calls.
+ */
+int spi_flash_cmd_rw_frame(struct spi_slave *spi, const u8 *cmd,
+		size_t cmd_len, void *data, size_t data_len);
+
  /* Manufacturer-specific probe functions */
  struct spi_flash *spi_flash_probe_spansion(struct spi_slave *spi, u8 *idcode);
  struct spi_flash *spi_flash_probe_atmel(struct spi_slave *spi, u8 *idcode);
-- 
1.7.0.4