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spi: dw: Add compatible for Intel Mount Evans SoC 

The Intel Mount Evans SoC's Integrated Management Complex uses the SPI
controller for access to a NOR SPI FLASH. However, the SoC doesn't
provide a mechanism to override the native chip select signal.

This driver doesn't use DMA for memory operations when a chip select
override is not provided due to the native chip select timing behavior.
As a result no DMA configuration is done for the controller and this
configuration is not tested.

The controller also has an errata where a full TX FIFO can result in
data corruption. The suggested workaround is to never completely fill
the FIFO. The TX FIFO has a size of 32 so the fifo_len is set to 31.

Signed-off-by: Abe Kohandel <abe.kohandel@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230606145402.474866-2-abe.kohandel@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Abe Kohandel 2023-06-06 07:54:01 -07:00 committed by Mark Brown
parent 8098a931c0
commit 0760d5d0e9
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GPG Key ID: 24D68B725D5487D0
1 changed files with 29 additions and 0 deletions
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29
drivers/spi/spi-dw-mmio.c
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@ -236,6 +236,31 @@ static int dw_spi_intel_init(struct platform_device *pdev,
return 0;
}
/*
* The Intel Mount Evans SoC's Integrated Management Complex uses the
* SPI controller for access to a NOR SPI FLASH. However, the SoC doesn't
* provide a mechanism to override the native chip select signal.
*
* This driver doesn't use DMA for memory operations when a chip select
* override is not provided due to the native chip select timing behavior.
* As a result no DMA configuration is done for the controller and this
* configuration is not tested.
*/
static int dw_spi_mountevans_imc_init(struct platform_device *pdev,
struct dw_spi_mmio *dwsmmio)
{
/*
* The Intel Mount Evans SoC's Integrated Management Complex DW
* apb_ssi_v4.02a controller has an errata where a full TX FIFO can
* result in data corruption. The suggested workaround is to never
* completely fill the FIFO. The TX FIFO has a size of 32 so the
* fifo_len is set to 31.
*/
dwsmmio->dws.fifo_len = 31;
return 0;
}
static int dw_spi_canaan_k210_init(struct platform_device *pdev,
struct dw_spi_mmio *dwsmmio)
{
@ -405,6 +430,10 @@ static const struct of_device_id dw_spi_mmio_of_match[] = {
{ .compatible = "snps,dwc-ssi-1.01a", .data = dw_spi_hssi_init},
{ .compatible = "intel,keembay-ssi", .data = dw_spi_intel_init},
{ .compatible = "intel,thunderbay-ssi", .data = dw_spi_intel_init},
{
.compatible = "intel,mountevans-imc-ssi",
.data = dw_spi_mountevans_imc_init,
},
{ .compatible = "microchip,sparx5-spi", dw_spi_mscc_sparx5_init},
{ .compatible = "canaan,k210-spi", dw_spi_canaan_k210_init},
{ .compatible = "amd,pensando-elba-spi", .data = dw_spi_elba_init},