spi: Change spi_xfer to work in units of bytes instead of bits.

Whenever spi_xfer is called and whenver it's implemented, the natural unit for
the amount of data being transfered is bytes. The API expected things to be
expressed in bits, however, which led to a lot of multiplying and dividing by
eight, and checkes to make sure things were multiples of eight. All of that
can now be removed.

BUG=None
TEST=Built and booted on link, falco, peach_pit and nyan and looked for SPI
errors in the firmware log. Built for rambi.
BRANCH=None

Change-Id: I02365bdb6960a35def7be7a0cd1aa0a2cc09392f
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: https://chromium-review.googlesource.com/192049
Reviewed-by: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
[km: cherry-pick from chromium]
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/6175
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

9 files changed, 37 insertions, 74 deletions

diff --git a/src/cpu/samsung/exynos5420/spi.c b/src/cpu/samsung/exynos5420/spi.c
index 5c546cc14c..46b9ced4b3 100644
--- a/src/cpu/samsung/exynos5420/spi.c
+++ b/src/cpu/samsung/exynos5420/spi.c
@@ -258,15 +258,13 @@ int spi_claim_bus(struct spi_slave *slave)
 	return 0;
 }
 
-int spi_xfer(struct spi_slave *slave, const void *dout, unsigned int bitsout,
-	     void *din, unsigned int bitsin)
+int spi_xfer(struct spi_slave *slave, const void *dout, unsigned int out_bytes,
+	     void *din, unsigned int in_bytes)
 {
-	unsigned int out_bytes = bitsout / 8, in_bytes = bitsin / 8;
 	uint8_t *out_ptr = (uint8_t *)dout, *in_ptr = (uint8_t *)din;
 	int offset, todo, len;
 	int ret = 0;
 
-	ASSERT(bitsout % 8 == 0 && bitsin % 8 == 0);
 	len = MAX(out_bytes, in_bytes);
 
 	/*
diff --git a/src/drivers/spi/spi_flash.c b/src/drivers/spi/spi_flash.c
index 9b676ae61f..f3a5906a00 100644
--- a/src/drivers/spi/spi_flash.c
+++ b/src/drivers/spi/spi_flash.c
@@ -28,7 +28,7 @@ static void spi_flash_addr(u32 addr, u8 *cmd)
 
 int spi_flash_cmd(struct spi_slave *spi, u8 cmd, void *response, size_t len)
 {
-	int ret = spi_xfer(spi, &cmd, 8, response, len * 8);
+	int ret = spi_xfer(spi, &cmd, sizeof(cmd), response, len);
 	if (ret)
 		printk(BIOS_WARNING, "SF: Failed to send command %02x: %d\n", cmd, ret);
 
@@ -38,7 +38,7 @@ int spi_flash_cmd(struct spi_slave *spi, u8 cmd, void *response, size_t len)
 int spi_flash_cmd_read(struct spi_slave *spi, const u8 *cmd,
 		size_t cmd_len, void *data, size_t data_len)
 {
-	int ret = spi_xfer(spi, cmd, cmd_len * 8, data, data_len * 8);
+	int ret = spi_xfer(spi, cmd, cmd_len, data, data_len);
 	if (ret) {
 		printk(BIOS_WARNING, "SF: Failed to send read command (%zu bytes): %d\n",
 				data_len, ret);
@@ -55,7 +55,7 @@ int spi_flash_cmd_write(struct spi_slave *spi, const u8 *cmd, size_t cmd_len,
 	memcpy(buff, cmd, cmd_len);
 	memcpy(buff + cmd_len, data, data_len);
 
-	ret = spi_xfer(spi, buff, (cmd_len + data_len) * 8, NULL, 0);
+	ret = spi_xfer(spi, buff, cmd_len + data_len, NULL, 0);
 	if (ret) {
 		printk(BIOS_WARNING, "SF: Failed to send write command (%zu bytes): %d\n",
 				data_len, ret);
diff --git a/src/ec/google/chromeec/ec_spi.c b/src/ec/google/chromeec/ec_spi.c
index 012a4cace5..d6b7b0c4ea 100644
--- a/src/ec/google/chromeec/ec_spi.c
+++ b/src/ec/google/chromeec/ec_spi.c
@@ -31,8 +31,8 @@ static int crosec_spi_io(uint8_t *write_bytes, size_t write_size,
 	int rv;
 
 	spi_claim_bus(slave);
-	rv = spi_xfer(slave, write_bytes, write_size * 8, read_bytes,
-		      read_size * 8);
+	rv = spi_xfer(slave, write_bytes, write_size, read_bytes,
+		      read_size);
 	spi_release_bus(slave);
 
 	if (rv != 0) {
diff --git a/src/include/spi-generic.h b/src/include/spi-generic.h
index b7a14f9342..6c62de6d1d 100644
--- a/src/include/spi-generic.h
+++ b/src/include/spi-generic.h
@@ -120,27 +120,17 @@ void spi_release_bus(struct spi_slave *slave);
 /*-----------------------------------------------------------------------
  * SPI transfer
  *
- * This writes "bitlen" bits out the SPI MOSI port and simultaneously clocks
- * "bitlen" bits in the SPI MISO port.  That's just the way SPI works.
- *
- * The source of the outgoing bits is the "dout" parameter and the
- * destination of the input bits is the "din" parameter.  Note that "dout"
- * and "din" can point to the same memory location, in which case the
- * input data overwrites the output data (since both are buffered by
- * temporary variables, this is OK).
- *
  * spi_xfer() interface:
  *   slave:	The SPI slave which will be sending/receiving the data.
- *   dout:	Pointer to a string of bits to send out.  The bits are
- *		held in a byte array and are sent MSB first.
- *   bitsout:	How many bits to write.
- *   din:	Pointer to a string of bits that will be filled in.
- *   bitsin:	How many bits to read.
+ *   dout:	Pointer to a string of bytes to send out.
+ *   bytesout:	How many bytes to write.
+ *   din:	Pointer to a string of bytes that will be filled in.
+ *   bytesin:	How many bytes to read.
  *
  *   Returns: 0 on success, not 0 on failure
  */
-int  spi_xfer(struct spi_slave *slave, const void *dout, unsigned int bitsout,
-		void *din, unsigned int bitsin);
+int  spi_xfer(struct spi_slave *slave, const void *dout, unsigned int bytesout,
+		void *din, unsigned int bytesin);
 
 /*-----------------------------------------------------------------------
  * Determine if a SPI chipselect is valid.
@@ -196,7 +186,7 @@ static inline int spi_w8r8(struct spi_slave *slave, unsigned char byte)
 	dout[0] = byte;
 	dout[1] = 0;
 
-	ret = spi_xfer(slave, dout, 16, din, 16);
+	ret = spi_xfer(slave, dout, 2, din, 2);
 	return ret < 0 ? ret : din[1];
 }
 
diff --git a/src/soc/intel/baytrail/spi.c b/src/soc/intel/baytrail/spi.c
index d75caca7af..b649f53411 100644
--- a/src/soc/intel/baytrail/spi.c
+++ b/src/soc/intel/baytrail/spi.c
@@ -500,7 +500,7 @@ static int ich_status_poll(u16 bitmask, int wait_til_set)
 }
 
 int spi_xfer(struct spi_slave *slave, const void *dout,
-		unsigned int bitsout, void *din, unsigned int bitsin)
+		unsigned int bytesout, void *din, unsigned int bytesin)
 {
 	uint16_t control;
 	int16_t opcode_index;
@@ -508,26 +508,21 @@ int spi_xfer(struct spi_slave *slave, const void *dout,
 	int status;
 
 	spi_transaction trans = {
-		dout, bitsout / 8,
-		din, bitsin / 8,
+		dout, bytesout,
+		din, bytesin,
 		0xff, 0xff, 0
 	};
 
 	/* There has to always at least be an opcode. */
-	if (!bitsout || !dout) {
+	if (!bytesout || !dout) {
 		printk(BIOS_DEBUG, "ICH SPI: No opcode for transfer\n");
 		return -1;
 	}
 	/* Make sure if we read something we have a place to put it. */
-	if (bitsin != 0 && !din) {
+	if (bytesin != 0 && !din) {
 		printk(BIOS_DEBUG, "ICH SPI: Read but no target buffer\n");
 		return -1;
 	}
-	/* Right now we don't support writing partial bytes. */
-	if (bitsout % 8 || bitsin % 8) {
-		printk(BIOS_DEBUG, "ICH SPI: Accessing partial bytes not supported\n");
-		return -1;
-	}
 
 	if (ich_status_poll(SPIS_SCIP, 0) == -1)
 		return -1;
diff --git a/src/soc/intel/fsp_baytrail/spi.c b/src/soc/intel/fsp_baytrail/spi.c
index 5e8da95d3e..50f11231da 100644
--- a/src/soc/intel/fsp_baytrail/spi.c
+++ b/src/soc/intel/fsp_baytrail/spi.c
@@ -498,7 +498,7 @@ static int ich_status_poll(u16 bitmask, int wait_til_set)
 }
 
 int spi_xfer(struct spi_slave *slave, const void *dout,
-		unsigned int bitsout, void *din, unsigned int bitsin)
+		unsigned int bytesout, void *din, unsigned int bytesin)
 {
 	uint16_t control;
 	int16_t opcode_index;
@@ -506,26 +506,21 @@ int spi_xfer(struct spi_slave *slave, const void *dout,
 	int status;
 
 	spi_transaction trans = {
-		dout, bitsout / 8,
-		din, bitsin / 8,
+		dout, bytesout,
+		din, bytesin,
 		0xff, 0xff, 0
 	};
 
 	/* There has to always at least be an opcode. */
-	if (!bitsout || !dout) {
+	if (!bytesout || !dout) {
 		printk(BIOS_DEBUG, "ICH SPI: No opcode for transfer\n");
 		return -1;
 	}
 	/* Make sure if we read something we have a place to put it. */
-	if (bitsin != 0 && !din) {
+	if (bytesin != 0 && !din) {
 		printk(BIOS_DEBUG, "ICH SPI: Read but no target buffer\n");
 		return -1;
 	}
-	/* Right now we don't support writing partial bytes. */
-	if (bitsout % 8 || bitsin % 8) {
-		printk(BIOS_DEBUG, "ICH SPI: Accessing partial bytes not supported\n");
-		return -1;
-	}
 
 	if (ich_status_poll(SPIS_SCIP, 0) == -1)
 		return -1;
diff --git a/src/southbridge/amd/agesa/hudson/spi.c b/src/southbridge/amd/agesa/hudson/spi.c
index c19d1a0ff8..720b26f83e 100644
--- a/src/southbridge/amd/agesa/hudson/spi.c
+++ b/src/southbridge/amd/agesa/hudson/spi.c
@@ -87,21 +87,14 @@ void spi_init(void)
 }
 
 int spi_xfer(struct spi_slave *slave, const void *dout,
-		unsigned int bitsout, void *din, unsigned int bitsin)
+		unsigned int bytesout, void *din, unsigned int bytesin)
 {
 	/* First byte is cmd which can not being sent through FIFO. */
-	uint8_t cmd = *(uint8_t *)dout++;
-	uint8_t readoffby1;
-#if !CONFIG_SOUTHBRIDGE_AMD_AGESA_YANGTZE
-	uint8_t readwrite;
-#endif
-	uint8_t bytesout, bytesin;
-	uint8_t count;
-
-	bitsout -= 8;
-	bytesout = bitsout / 8;
-	bytesin  = bitsin / 8;
+	u8 cmd = *(u8 *)dout++;
+	u8 readoffby1;
+	u8 count;
 
+	bytesout--;
 	readoffby1 = bytesout ? 0 : 1;
 
 #if CONFIG_SOUTHBRIDGE_AMD_AGESA_YANGTZE
@@ -110,7 +103,7 @@ int spi_xfer(struct spi_slave *slave, const void *dout,
 	spi_write(0x1E, 6);
 	spi_write(0x1F, bytesin);  /* SpiExtRegIndx [6] - RxByteCount */
 #else
-	readwrite = (bytesin + readoffby1) << 4 | bytesout;
+	u8 readwrite = (bytesin + readoffby1) << 4 | bytesout;
 	spi_write(SPI_REG_CNTRL01, readwrite);
 #endif
 	spi_write(SPI_REG_OPCODE, cmd);
diff --git a/src/southbridge/amd/cimx/sb800/spi.c b/src/southbridge/amd/cimx/sb800/spi.c
index d059f5eb00..a46349e933 100644
--- a/src/southbridge/amd/cimx/sb800/spi.c
+++ b/src/southbridge/amd/cimx/sb800/spi.c
@@ -57,18 +57,15 @@ void spi_init()
 }
 
 int spi_xfer(struct spi_slave *slave, const void *dout,
-		unsigned int bitsout, void *din, unsigned int bitsin)
+		unsigned int bytesout, void *din, unsigned int bytesin)
 {
 	/* First byte is cmd which can not being sent through FIFO. */
 	u8 cmd = *(u8 *)dout++;
 	u8 readoffby1;
 	u8 readwrite;
-	u8 bytesout, bytesin;
 	u8 count;
 
-	bitsout -= 8;
-	bytesout = bitsout / 8;
-	bytesin  = bitsin / 8;
+	bytesout--;
 
 	readoffby1 = bytesout ? 0 : 1;
 
diff --git a/src/southbridge/intel/common/spi.c b/src/southbridge/intel/common/spi.c
index 14d2f54d28..76fd22691f 100644
--- a/src/southbridge/intel/common/spi.c
+++ b/src/southbridge/intel/common/spi.c
@@ -551,7 +551,7 @@ static int spi_is_multichip (void)
 }
 
 int spi_xfer(struct spi_slave *slave, const void *dout,
-		unsigned int bitsout, void *din, unsigned int bitsin)
+		unsigned int bytesout, void *din, unsigned int bytesin)
 {
 	uint16_t control;
 	int16_t opcode_index;
@@ -559,26 +559,21 @@ int spi_xfer(struct spi_slave *slave, const void *dout,
 	int status;
 
 	spi_transaction trans = {
-		dout, bitsout / 8,
-		din, bitsin / 8,
+		dout, bytesout,
+		din, bytesin,
 		0xff, 0xff, 0
 	};
 
 	/* There has to always at least be an opcode. */
-	if (!bitsout || !dout) {
+	if (!bytesout || !dout) {
 		printk(BIOS_DEBUG, "ICH SPI: No opcode for transfer\n");
 		return -1;
 	}
 	/* Make sure if we read something we have a place to put it. */
-	if (bitsin != 0 && !din) {
+	if (bytesin != 0 && !din) {
 		printk(BIOS_DEBUG, "ICH SPI: Read but no target buffer\n");
 		return -1;
 	}
-	/* Right now we don't support writing partial bytes. */
-	if (bitsout % 8 || bitsin % 8) {
-		printk(BIOS_DEBUG, "ICH SPI: Accessing partial bytes not supported\n");
-		return -1;
-	}
 
 	if (ich_status_poll(SPIS_SCIP, 0) == -1)
 		return -1;