drivers/spi/spi-generic: document SPI_CNTRLR_DEDUCT_CMD_LEN better

This should make it a bit clearer what the differences between
SPI_CNTRLR_DEDUCT_OPCODE_LEN and SPI_CNTRLR_DEDUCT_CMD_LEN and the
corresponding functionality in spi_crop_chunk are.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I809adebb182fc0866b93372b5b486117176da388
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60122
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
This commit is contained in:
Felix Held 2021-12-10 18:38:16 +01:00
parent e3ae755575
commit 55dce1d55d
2 changed files with 6 additions and 1 deletions

View File

@ -98,6 +98,10 @@ unsigned int spi_crop_chunk(const struct spi_slave *slave, unsigned int cmd_len,
if (deduct_opcode_len)
cmd_len--;
/* Subtract command length from useable buffer size. If
deduct_opcode_len is set, only subtract the number command bytes
after the opcode. If the adjusted cmd_len is larger than ctrlr_max
return 0 to inidicate an error. */
if (deduct_cmd_len) {
if (ctrlr_max >= cmd_len) {
ctrlr_max -= cmd_len;

View File

@ -111,7 +111,8 @@ enum ctrlr_prot_type {
enum {
/* Deduct the command length from the spi_crop_chunk() calculation for
sizing a transaction. */
sizing a transaction. If SPI_CNTRLR_DEDUCT_OPCODE_LEN is set, only
the bytes after the command byte will be deducted. */
SPI_CNTRLR_DEDUCT_CMD_LEN = 1 << 0,
/* Remove the opcode size from the command length used in the
spi_crop_chunk() calculation. Controllers which have a dedicated