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drivers/spi: reduce confusion in the API

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Julius brought up confusion about the current spi api in [1]. In order
alleviate the confusion stemming from supporting x86 spi flash
controllers:

- Remove spi_xfer_two_vectors() which was fusing transactions to
  accomodate the limitations of the spi controllers themselves.
- Add spi_flash_vector_helper() for the x86 spi flash controllers to
  utilize in validating driver/controller current assumptions.
- Remove the xfer() callback in the x86 spi flash drivers which
  will trigger an error as these controllers can't support the api.

[1] https://mail.coreboot.org/pipermail/coreboot/2018-April/086561.html

Change-Id: Id88adc6ad5234c29a739d43521c5f344bb7d3217
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/25745
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
This commit is contained in:
Aaron Durbin
2018-04-19 21:15:25 -06:00
parent 6c2b10e989
commit 851dde8255
15 changed files with 147 additions and 95 deletions
Download Patch File Download Diff File Expand all files Collapse all files

53
src/drivers/spi/spi-generic.c
View File

@@ -146,56 +146,3 @@ int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)
return 0;
}
static int spi_xfer_combine_two_vectors(const struct spi_slave *slave,
struct spi_op *v1, struct spi_op *v2)
{
struct spi_op op = {
.dout = v1->dout, .bytesout = v1->bytesout,
.din = v2->din, .bytesin = v2->bytesin,
};
int ret;
/*
* Combine two vectors only if:
* v1 has non-NULL dout and NULL din and
* v2 has non-NULL din and NULL dout and
*
* In all other cases, do not combine the two vectors.
*/
if ((!v1->dout || v1->din) || (v2->dout || !v2->din))
return -1;
ret = spi_xfer_single_op(slave, &op);
v1->status = v2->status = op.status;
return ret;
}
/*
* Helper function to allow chipsets to combine two vectors if possible. This
* function can only handle upto 2 vectors.
*
* Two vectors are combined if first vector has a non-NULL dout and NULL din and
* second vector has a non-NULL din and NULL dout. Otherwise, each vector is
* operated upon one at a time.
*
* Returns 0 on success and non-zero on failure.
*/
int spi_xfer_two_vectors(const struct spi_slave *slave,
struct spi_op vectors[], size_t count)
{
int ret;
assert (count <= 2);
if (count == 2) {
ret = spi_xfer_combine_two_vectors(slave, &vectors[0],
&vectors[1]);
if (!ret || (vectors[0].status != SPI_OP_NOT_EXECUTED))
return ret;
}
return spi_xfer_vector_default(slave, vectors, count);
}

48
src/drivers/spi/spi_flash.c
View File

@@ -519,3 +519,51 @@ int spi_flash_ctrlr_protect_region(const struct spi_flash *flash,
return -1;
}
int spi_flash_vector_helper(const struct spi_slave *slave,
struct spi_op vectors[], size_t count,
int (*func)(const struct spi_slave *slave, const void *dout,
size_t bytesout, void *din, size_t bytesin))
{
int ret;
void *din;
size_t bytes_in;
if (count < 1 || count > 2)
return -1;
/* SPI flash commands always have a command first... */
if (!vectors[0].dout || !vectors[0].bytesout)
return -1;
/* And not read any data during the command. */
if (vectors[0].din || vectors[0].bytesin)
return -1;
if (count == 2) {
/* If response bytes requested ensure the buffer is valid. */
if (vectors[1].bytesin && !vectors[1].din)
return -1;
/* No sends can accompany a receive. */
if (vectors[1].dout || vectors[1].bytesout)
return -1;
din = vectors[1].din;
bytes_in = vectors[1].bytesin;
} else {
din = NULL;
bytes_in = 0;
}
ret = func(slave, vectors[0].dout, vectors[0].bytesout, din, bytes_in);
if (ret) {
vectors[0].status = SPI_OP_FAILURE;
if (count == 2)
vectors[1].status = SPI_OP_FAILURE;
} else {
vectors[0].status = SPI_OP_SUCCESS;
if (count == 2)
vectors[1].status = SPI_OP_SUCCESS;
}
return ret;
}