drivers/spi: Re-factor spi_crop_chunk

spi_crop_chunk is a property of the SPI controller since it depends
upon the maximum transfer size that is supported by the
controller. Also, it is possible to implement this within spi-generic
layer by obtaining following parameters from the controller:

1. max_xfer_size: Maximum transfer size supported by the controller
(Size of 0 indicates invalid size, and unlimited transfer size is
indicated by UINT32_MAX.)

2. deduct_cmd_len: Whether cmd_len needs to be deducted from the
max_xfer_size to determine max data size that can be
transferred. (This is used by the amd boards.)

Change-Id: I81c199413f879c664682088e93bfa3f91c6a46e5
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/19386
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Tested-by: coreboot org <coreboot.org@gmail.com>

src/drivers/spi/adesto.c

@@ -97,7 +97,7 @@ static int adesto_write(const struct spi_flash *flash, u32 offset, size_t len,
 	for (actual = 0; actual < len; actual += chunk_len) {
 		byte_addr = offset % page_size;
 		chunk_len = min(len - actual, page_size - byte_addr);
-		chunk_len = spi_crop_chunk(sizeof(cmd), chunk_len);
+		chunk_len = spi_crop_chunk(&flash->spi, sizeof(cmd), chunk_len);
 
 		cmd[0] = CMD_AT25DF_PP;
 		cmd[1] = (offset >> 16) & 0xff;

src/drivers/spi/amic.c

@@ -79,7 +79,7 @@ static int amic_write(const struct spi_flash *flash, u32 offset, size_t len,
 
 	for (actual = 0; actual < len; actual += chunk_len) {
 		chunk_len = min(len - actual, page_size - byte_addr);
-		chunk_len = spi_crop_chunk(sizeof(cmd), chunk_len);
+		chunk_len = spi_crop_chunk(&flash->spi, sizeof(cmd), chunk_len);
 
 		cmd[0] = CMD_A25_PP;
 		cmd[1] = (offset >> 16) & 0xff;

src/drivers/spi/atmel.c

@@ -125,7 +125,7 @@ static int atmel_write(const struct spi_flash *flash, u32 offset, size_t len,
 	for (actual = 0; actual < len; actual += chunk_len) {
 		byte_addr = offset % page_size;
 		chunk_len = min(len - actual, page_size - byte_addr);
-		chunk_len = spi_crop_chunk(sizeof(cmd), chunk_len);
+		chunk_len = spi_crop_chunk(&flash->spi, sizeof(cmd), chunk_len);
 
 		cmd[0] = CMD_AT25_PP;
 		cmd[1] = (offset >> 16) & 0xff;

src/drivers/spi/eon.c

@@ -95,7 +95,7 @@ static int eon_write(const struct spi_flash *flash,
 	for (actual = 0; actual < len; actual += chunk_len) {
 		byte_addr = offset % page_size;
 		chunk_len = min(len - actual, page_size - byte_addr);
-		chunk_len = spi_crop_chunk(sizeof(cmd), chunk_len);
+		chunk_len = spi_crop_chunk(&flash->spi, sizeof(cmd), chunk_len);
 
 		ret = spi_flash_cmd(&flash->spi, CMD_EN25_WREN, NULL, 0);
 		if (ret < 0) {

src/drivers/spi/gigadevice.c

@@ -136,7 +136,7 @@ static int gigadevice_write(const struct spi_flash *flash, u32 offset,
 	for (actual = 0; actual < len; actual += chunk_len) {
 		byte_addr = offset % page_size;
 		chunk_len = min(len - actual, page_size - byte_addr);
-		chunk_len = spi_crop_chunk(sizeof(cmd), chunk_len);
+		chunk_len = spi_crop_chunk(&flash->spi, sizeof(cmd), chunk_len);
 
 		ret = spi_flash_cmd(&flash->spi, CMD_GD25_WREN, NULL, 0);
 		if (ret < 0) {

src/drivers/spi/macronix.c

@@ -164,7 +164,7 @@ static int macronix_write(const struct spi_flash *flash, u32 offset, size_t len,
 	for (actual = 0; actual < len; actual += chunk_len) {
 		byte_addr = offset % page_size;
 		chunk_len = min(len - actual, page_size - byte_addr);
-		chunk_len = spi_crop_chunk(sizeof(cmd), chunk_len);
+		chunk_len = spi_crop_chunk(&flash->spi, sizeof(cmd), chunk_len);
 
 		cmd[0] = CMD_MX25XX_PP;
 		cmd[1] = (offset >> 16) & 0xff;

src/drivers/spi/spansion.c

@@ -217,7 +217,7 @@ static int spansion_write(const struct spi_flash *flash, u32 offset, size_t len,
 	for (actual = 0; actual < len; actual += chunk_len) {
 		byte_addr = offset % page_size;
 		chunk_len = min(len - actual, page_size - byte_addr);
-		chunk_len = spi_crop_chunk(sizeof(cmd), chunk_len);
+		chunk_len = spi_crop_chunk(&flash->spi, sizeof(cmd), chunk_len);
 
 		cmd[0] = CMD_S25FLXX_PP;
 		cmd[1] = (offset >> 16) & 0xff;

src/drivers/spi/spi-generic.c

@@ -88,6 +88,25 @@ int spi_xfer(const struct spi_slave *slave, const void *dout, size_t bytesout,
 	return -1;
 }
 
+unsigned int spi_crop_chunk(const struct spi_slave *slave, unsigned int cmd_len,
+			unsigned int buf_len)
+{
+	const struct spi_ctrlr *ctrlr = slave->ctrlr;
+	unsigned int ctrlr_max;
+
+	if (!ctrlr)
+		return 0;
+
+	ctrlr_max = ctrlr->max_xfer_size;
+
+	assert (ctrlr_max != 0);
+
+	if (ctrlr->deduct_cmd_len && (ctrlr_max > cmd_len))
+		ctrlr_max -= cmd_len;
+
+	return min(ctrlr_max, buf_len);
+}
+
 void __attribute__((weak)) spi_init(void)
 {
 	/* Default weak implementation - do nothing. */

src/drivers/spi/spiconsole.c

@@ -46,7 +46,7 @@ void spiconsole_tx_byte(unsigned char c) {
 	};
 
 	/* Verify the spi buffer is big enough to send even a single byte */
-	if (spi_crop_chunk(0,MAX_MSG_LENGTH) <
+	if (spi_crop_chunk(&slave, 0, MAX_MSG_LENGTH) <
 			sizeof(struct em100_msg_header) + 1)
 		return;
 
@@ -55,7 +55,7 @@ void spiconsole_tx_byte(unsigned char c) {
 
 	/* Send the data on newline or when the max spi length is reached */
 	if (c == '\n' || (sizeof(struct em100_msg_header) +
-			msg.header.msg_length == spi_crop_chunk(0,
+			msg.header.msg_length == spi_crop_chunk(&slave, 0,
 			MAX_MSG_LENGTH))) {
 		spi_xfer(&slave, &msg, sizeof(struct em100_msg_header) +
 				msg.header.msg_length, NULL, 0);

src/drivers/spi/sst.c

@@ -194,7 +194,7 @@ static int sst_write_256(const struct spi_flash *flash, u32 offset, size_t len,
 	for (actual = 0; actual < len; actual += chunk_len) {
 		byte_addr = offset % page_size;
 		chunk_len = min(len - actual, page_size - byte_addr);
-		chunk_len = spi_crop_chunk(sizeof(cmd), chunk_len);
+		chunk_len = spi_crop_chunk(&flash->spi, sizeof(cmd), chunk_len);
 
 		cmd[0] = CMD_SST_BP;
 		cmd[1] = (offset >> 16) & 0xff;

src/drivers/spi/stmicro.c

@@ -193,7 +193,7 @@ static int stmicro_write(const struct spi_flash *flash,
 	for (actual = 0; actual < len; actual += chunk_len) {
 		byte_addr = offset % page_size;
 		chunk_len = min(len - actual, page_size - byte_addr);
-		chunk_len = spi_crop_chunk(sizeof(cmd), chunk_len);
+		chunk_len = spi_crop_chunk(&flash->spi, sizeof(cmd), chunk_len);
 
 		cmd[0] = CMD_M25PXX_PP;
 		cmd[1] = (offset >> 16) & 0xff;

src/drivers/spi/winbond.c

@@ -155,7 +155,7 @@ static int winbond_write(const struct spi_flash *flash, u32 offset, size_t len,
 	for (actual = 0; actual < len; actual += chunk_len) {
 		byte_addr = offset % page_size;
 		chunk_len = min(len - actual, page_size - byte_addr);
-		chunk_len = spi_crop_chunk(sizeof(cmd), chunk_len);
+		chunk_len = spi_crop_chunk(&flash->spi, sizeof(cmd), chunk_len);
 
 		cmd[0] = CMD_W25_PP;
 		cmd[1] = (offset >> 16) & 0xff;

src/include/spi-generic.h

@@ -87,14 +87,27 @@ struct spi_cfg {
 	unsigned int data_bit_length;
 };
 
+/*
+ * If there is no limit on the maximum transfer size for the controller,
+ * max_xfer_size can be set to SPI_CTRLR_DEFAULT_MAX_XFER_SIZE which is equal to
+ * UINT32_MAX.
+ */
+#define SPI_CTRLR_DEFAULT_MAX_XFER_SIZE	(UINT32_MAX)
+
 /*-----------------------------------------------------------------------
- * Representation of a SPI contoller.
+ * Representation of a SPI controller.
  *
  * claim_bus:		Claim SPI bus and prepare for communication.
  * release_bus:	Release SPI bus.
  * setup:		Setup given SPI device bus.
  * xfer:		Perform one SPI transfer operation.
  * xfer_vector:	Vector of SPI transfer operations.
+ * max_xfer_size:	Maximum transfer size supported by the controller
+ *			(0 = invalid,
+ *			 SPI_CTRLR_DEFAULT_MAX_XFER_SIZE = unlimited)
+ * deduct_cmd_len:	Whether cmd_len should be deducted from max_xfer_size
+ *			when calculating max_data_size
+ *
  */
 struct spi_ctrlr {
 	int (*claim_bus)(const struct spi_slave *slave);
@@ -104,6 +117,8 @@ struct spi_ctrlr {
 		    size_t bytesout, void *din, size_t bytesin);
 	int (*xfer_vector)(const struct spi_slave *slave,
 			struct spi_op vectors[], size_t count);
+	uint32_t max_xfer_size;
+	bool deduct_cmd_len;
 };
 
 /*-----------------------------------------------------------------------
@@ -212,7 +227,14 @@ int spi_xfer(const struct spi_slave *slave, const void *dout, size_t bytesout,
 int spi_xfer_vector(const struct spi_slave *slave,
 		struct spi_op vectors[], size_t count);
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len);
+/*-----------------------------------------------------------------------
+ * Given command length and length of remaining data, return the maximum data
+ * that can be transferred in next spi_xfer.
+ *
+ * Returns: 0 on error, non-zero data size that can be xfered on success.
+ */
+unsigned int spi_crop_chunk(const struct spi_slave *slave, unsigned int cmd_len,
+			unsigned int buf_len);
 
 /*-----------------------------------------------------------------------
  * Write 8 bits, then read 8 bits.

src/soc/broadcom/cygnus/spi.c

@@ -280,6 +280,7 @@ static const struct spi_ctrlr spi_ctrlr = {
 	.release_bus = spi_ctrlr_release_bus,
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = 65535,
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)
@@ -318,8 +319,3 @@ int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)
 
 	return 0;
 }
-
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return min(65535, buf_len);
-}

src/soc/imgtec/pistachio/spi.c

@@ -538,6 +538,7 @@ static const struct spi_ctrlr spi_ctrlr = {
 	.release_bus = spi_ctrlr_release_bus,
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = IMGTEC_SPI_MAX_TRANSFER_SIZE,
 };
 
 /* Set up communications parameters for a SPI slave. */
@@ -585,8 +586,3 @@ int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)
 
 	return 0;
 }
-
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return min(IMGTEC_SPI_MAX_TRANSFER_SIZE, buf_len);
-}

src/soc/intel/baytrail/spi.c

@@ -19,6 +19,7 @@
 #include <bootstate.h>
 #include <delay.h>
 #include <arch/io.h>
+#include <commonlib/helpers.h>
 #include <console/console.h>
 #include <device/pci_ids.h>
 #include <spi_flash.h>
@@ -457,11 +458,6 @@ static int ich_status_poll(u16 bitmask, int wait_til_set)
 	return -1;
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return min(cntlr.databytes, buf_len);
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 		    size_t bytesout, void *din, size_t bytesin)
 {
@@ -613,6 +609,7 @@ static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 static const struct spi_ctrlr spi_ctrlr = {
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = member_size(ich9_spi_regs, fdata),
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/soc/intel/braswell/spi.c

@@ -16,6 +16,7 @@
 /* This file is derived from the flashrom project. */
 #include <arch/io.h>
 #include <bootstate.h>
+#include <commonlib/helpers.h>
 #include <console/console.h>
 #include <delay.h>
 #include <device/pci_ids.h>
@@ -438,11 +439,6 @@ static int ich_status_poll(u16 bitmask, int wait_til_set)
 	return -1;
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return min(cntlr.databytes, buf_len);
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 		    size_t bytesout, void *din, size_t bytesin)
 {
@@ -597,6 +593,7 @@ static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 static const struct spi_ctrlr spi_ctrlr = {
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = member_size(ich9_spi_regs, fdata),
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/soc/intel/broadwell/spi.c

@@ -16,6 +16,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <bootstate.h>
+#include <commonlib/helpers.h>
 #include <delay.h>
 #include <arch/io.h>
 #include <console/console.h>
@@ -454,11 +455,6 @@ static int ich_status_poll(u16 bitmask, int wait_til_set)
 	return -1;
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return min(cntlr.databytes, buf_len);
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 		    size_t bytesout, void *din, size_t bytesin)
 {
@@ -654,6 +650,7 @@ int spi_flash_protect(u32 start, u32 size)
 static const struct spi_ctrlr spi_ctrlr = {
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = member_size(ich9_spi_regs, fdata),
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/soc/intel/common/block/fast_spi/fast_spi_flash.c

@@ -364,4 +364,5 @@ static int fast_spi_flash_ctrlr_setup(const struct spi_slave *dev)
 
 const struct spi_ctrlr fast_spi_flash_ctrlr = {
 	.setup = fast_spi_flash_ctrlr_setup,
+	.max_xfer_size = SPI_CTRLR_DEFAULT_MAX_XFER_SIZE,
 };

src/soc/intel/common/block/gspi/gspi.c

@@ -611,4 +611,5 @@ const struct spi_ctrlr gspi_ctrlr = {
 	.release_bus = gspi_cs_deassert,
 	.setup = gspi_ctrlr_setup,
 	.xfer = gspi_ctrlr_xfer,
+	.max_xfer_size = SPI_CTRLR_DEFAULT_MAX_XFER_SIZE,
 };

src/soc/intel/fsp_baytrail/spi.c

@@ -18,6 +18,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
+#include <commonlib/helpers.h>
 #include <delay.h>
 #include <arch/io.h>
 #include <console/console.h>
@@ -438,11 +439,6 @@ static int ich_status_poll(uint16_t bitmask, int wait_til_set)
 	return -1;
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return min(cntlr.databytes, buf_len);
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 		    size_t bytesout, void *din, size_t bytesin)
 {
@@ -594,6 +590,7 @@ spi_xfer_exit:
 static const struct spi_ctrlr spi_ctrlr = {
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = member_size(ich9_spi_regs, fdata),
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/soc/intel/fsp_broadwell_de/spi.c

@@ -19,6 +19,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <delay.h>
+#include <commonlib/helpers.h>
 #include <arch/io.h>
 #include <console/console.h>
 #include <device/pci_ids.h>
@@ -452,11 +453,6 @@ static int ich_status_poll(uint16_t bitmask, int wait_til_set)
 	return -1;
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return min(cntlr.databytes, buf_len);
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 		    size_t bytesout, void *din, size_t bytesin)
 {
@@ -610,6 +606,7 @@ spi_xfer_exit:
 static const struct spi_ctrlr spi_ctrlr = {
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = member_size(ich9_spi_regs, fdata),
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/soc/marvell/armada38x/spi.c

@@ -454,11 +454,6 @@ static void spi_ctrlr_release_bus(const struct spi_slave *slave)
 	mv_spi_cs_deassert(slave->bus);
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return buf_len;
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave,
 		       const void *dout,
 		       size_t out_bytes,
@@ -480,6 +475,7 @@ static const spi_ctrlr spi_ctrlr = {
 	.claim_bus = spi_ctrlr_claim_bus,
 	.release_bus = spi_ctrlr_release_bus,
 	.xfer = spi_ctrlr_xfer,
+	.max_xfer_size = SPI_CTRLR_DEFAULT_MAX_XFER_SIZE,
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/soc/marvell/bg4cd/spi.c

@@ -19,8 +19,3 @@ int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)
 {
 	return -1;
 }
-
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return buf_len;
-}

src/soc/mediatek/mt8173/flash_controller.c

@@ -108,11 +108,6 @@ static int sector_erase(int offset)
 	return 0;
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return min(65535, buf_len);
-}
-
 static int dma_read(u32 addr, u8 *buf, u32 len, uintptr_t dma_buf,
 		    size_t dma_buf_len)
 {

src/soc/mediatek/mt8173/spi.c

@@ -294,6 +294,7 @@ static const struct spi_ctrlr spi_ctrlr = {
 	.release_bus = spi_ctrlr_release_bus,
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = 65535,
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/soc/nvidia/tegra124/spi.c

@@ -714,11 +714,6 @@ static int xfer_finish(struct tegra_spi_channel *spi)
 	return ret;
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return buf_len;
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 			  size_t out_bytes, void *din, size_t in_bytes)
 {
@@ -802,6 +797,7 @@ static const struct spi_ctrlr spi_ctrlr = {
 	.claim_bus = spi_ctrlr_claim_bus,
 	.release_bus = spi_ctrlr_release_bus,
 	.xfer = spi_ctrlr_xfer,
+	.max_xfer_size = SPI_CTRLR_DEFAULT_MAX_XFER_SIZE,
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/soc/nvidia/tegra210/spi.c

@@ -750,11 +750,6 @@ static int xfer_finish(struct tegra_spi_channel *spi)
 	return ret;
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return buf_len;
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 			  size_t out_bytes, void *din, size_t in_bytes)
 {
@@ -838,6 +833,7 @@ static const struct spi_ctrlr spi_ctrlr = {
 	.claim_bus = spi_ctrlr_claim_bus,
 	.release_bus = spi_ctrlr_release_bus,
 	.xfer = spi_ctrlr_xfer,
+	.max_xfer_size = SPI_CTRLR_DEFAULT_MAX_XFER_SIZE,
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/soc/qualcomm/ipq40xx/spi.c

@@ -410,11 +410,6 @@ static void enable_io_config(struct ipq_spi_slave *ds,
 	return;
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return min(MAX_PACKET_COUNT, buf_len);
-}
-
 /*
  * Function to read bytes number of data from the Input FIFO
  */
@@ -657,6 +652,7 @@ static const struct spi_ctrlr spi_ctrlr = {
 	.release_bus = spi_ctrlr_release_bus,
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = MAX_PACKET_COUNT,
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/soc/qualcomm/ipq806x/spi.c

@@ -683,11 +683,6 @@ static int spi_xfer_rx_packet(struct ipq_spi_slave *ds,
 	return config_spi_state(ds, SPI_RESET_STATE);
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return min(MAX_PACKET_COUNT, buf_len);
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 			size_t out_bytes, void *din, size_t in_bytes)
 {
@@ -761,6 +756,7 @@ static const struct spi_ctrlr spi_ctrlr = {
 	.claim_bus = spi_ctrlr_claim_bus,
 	.release_bus = spi_ctrlr_release_bus,
 	.xfer = spi_ctrlr_xfer,
+	.max_xfer_size = MAX_PACKET_COUNT,
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/soc/rockchip/common/spi.c

@@ -251,11 +251,6 @@ static int do_xfer(struct rockchip_spi *regs, bool use_16bit, const void *dout,
 	return 0;
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return min(65535, buf_len);
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 			  size_t bytes_out, void *din, size_t bytes_in)
 {
@@ -332,6 +327,7 @@ static const struct spi_ctrlr spi_ctrlr = {
 	.claim_bus = spi_ctrlr_claim_bus,
 	.release_bus = spi_ctrlr_release_bus,
 	.xfer = spi_ctrlr_xfer,
+	.max_xfer_size = 65535,
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/soc/samsung/exynos5420/spi.c

@@ -212,6 +212,7 @@ static const struct spi_ctrlr spi_ctrlr = {
 	.claim_bus = spi_ctrlr_claim_bus,
 	.release_bus = spi_ctrlr_release_bus,
 	.xfer = spi_ctrlr_xfer,
+	.max_xfer_size = SPI_CTRLR_DEFAULT_MAX_XFER_SIZE,
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/southbridge/amd/agesa/hudson/spi.c

@@ -85,11 +85,6 @@ 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);
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 		size_t bytesout, void *din, size_t bytesin)
 {
@@ -168,6 +163,8 @@ int chipset_volatile_group_end(const struct spi_flash *flash)
 static const struct spi_ctrlr spi_ctrlr = {
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = AMD_SB_SPI_TX_LEN,
+	.deduct_cmd_len = true,
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/southbridge/amd/cimx/sb800/spi.c

@@ -54,11 +54,6 @@ 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);
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 		size_t bytesout, void *din, size_t bytesin)
 {
@@ -159,6 +154,8 @@ int chipset_volatile_group_end(const struct spi_flash *flash)
 static const struct spi_ctrlr spi_ctrlr = {
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = AMD_SB_SPI_TX_LEN,
+	.deduct_cmd_len = true,
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/southbridge/amd/sb700/spi.c

@@ -40,11 +40,6 @@ void spi_init(void)
 	/* Not needed */
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return min(AMD_SB_SPI_TX_LEN - cmd_len, buf_len);
-}
-
 static void reset_internal_fifo_pointer(void)
 {
 	uint32_t spibar = get_spi_bar();
@@ -121,6 +116,8 @@ static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 static const struct spi_ctrlr spi_ctrlr = {
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = AMD_SB_SPI_TX_LEN,
+	.deduct_cmd_len = true,
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/southbridge/intel/common/spi.c

@@ -19,6 +19,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <bootstate.h>
+#include <commonlib/helpers.h>
 #include <delay.h>
 #include <arch/io.h>
 #include <console/console.h>
@@ -504,11 +505,6 @@ 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);
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 		size_t bytesout, void *din, size_t bytesin)
 {
@@ -660,6 +656,7 @@ static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 static const struct spi_ctrlr spi_ctrlr = {
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = member_size(ich9_spi_regs, fdata),
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)

src/southbridge/intel/fsp_rangeley/spi.c

@@ -17,6 +17,7 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
+#include <commonlib/helpers.h>
 #include <delay.h>
 #include <arch/io.h>
 #include <console/console.h>
@@ -569,11 +570,6 @@ static int ich_status_poll(u16 bitmask, int wait_til_set)
 	return -1;
 }
 
-unsigned int spi_crop_chunk(unsigned int cmd_len, unsigned int buf_len)
-{
-	return min(cntlr.databytes, buf_len);
-}
-
 static int spi_ctrlr_xfer(const struct spi_slave *slave, const void *dout,
 		size_t bytesout, void *din, size_t bytesin)
 {
@@ -725,6 +721,7 @@ spi_xfer_exit:
 static const struct spi_ctrlr spi_ctrlr = {
 	.xfer = spi_ctrlr_xfer,
 	.xfer_vector = spi_xfer_two_vectors,
+	.max_xfer_size = member_size(ich10_spi_regs, fdata),
 };
 
 int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)