SPI: Split writes using spi_crop_chunk()

SPI controllers in Intel and AMD bridges have a slightly different
restriction on how long transactions they can handle.

Change-Id: I3d149d4b7e7e9633482a153d5e380a86c553d871
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/6163
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>

3 files changed, 19 insertions, 1 deletions

diff --git a/src/southbridge/amd/agesa/hudson/spi.c b/src/southbridge/amd/agesa/hudson/spi.c
index 720b26f83e..f050a63f91 100644
--- a/src/southbridge/amd/agesa/hudson/spi.c
+++ b/src/southbridge/amd/agesa/hudson/spi.c
@@ -42,6 +42,7 @@ static int bus_claimed = 0;
 #define SPI_REG_CNTRL11		0xd
  #define CNTRL11_FIFOPTR_MASK	0x07
 
+#define AMD_SB_SPI_TX_LEN	64
 
 static u32 spibar;
 
@@ -86,6 +87,11 @@ void spi_init(void)
 	spibar = pci_read_config32(dev, 0xA0) & ~0x1F;
 }
 
+unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
+{
+	return min(AMD_SB_SPI_TX_LEN - cmd_len, buf_len);
+}
+
 int spi_xfer(struct spi_slave *slave, const void *dout,
 		unsigned int bytesout, void *din, unsigned int bytesin)
 {
diff --git a/src/southbridge/amd/cimx/sb800/spi.c b/src/southbridge/amd/cimx/sb800/spi.c
index a46349e933..e5b2407082 100644
--- a/src/southbridge/amd/cimx/sb800/spi.c
+++ b/src/southbridge/amd/cimx/sb800/spi.c
@@ -32,6 +32,8 @@
 static int bus_claimed = 0;
 #endif
 
+#define AMD_SB_SPI_TX_LEN	8
+
 static u32 spibar;
 
 static void reset_internal_fifo_pointer(void)
@@ -56,6 +58,11 @@ void spi_init()
 	spibar = pci_read_config32(dev, 0xA0) & ~0x1F;
 }
 
+unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
+{
+	return min(AMD_SB_SPI_TX_LEN - cmd_len, buf_len);
+}
+
 int spi_xfer(struct spi_slave *slave, const void *dout,
 		unsigned int bytesout, void *din, unsigned int bytesin)
 {
diff --git a/src/southbridge/intel/common/spi.c b/src/southbridge/intel/common/spi.c
index 76fd22691f..8e7192b49f 100644
--- a/src/southbridge/intel/common/spi.c
+++ b/src/southbridge/intel/common/spi.c
@@ -550,6 +550,11 @@ static int spi_is_multichip (void)
 	return !!((cntlr.flmap0 >> 8) & 3);
 }
 
+unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
+{
+	return min(cntlr.databytes, buf_len);
+}
+
 int spi_xfer(struct spi_slave *slave, const void *dout,
 		unsigned int bytesout, void *din, unsigned int bytesin)
 {
@@ -639,7 +644,7 @@ int spi_xfer(struct spi_slave *slave, const void *dout,
 	 */
 	if (trans.bytesout > cntlr.databytes) {
 		printk(BIOS_DEBUG, "ICH SPI: Too much to write. Does your SPI chip driver use"
-		     " CONTROLLER_PAGE_LIMIT?\n");
+		     " spi_crop_chunk()?\n");
 		return -1;
 	}