This is a note to let you know that I've just added the patch titled
spi: dw: Add compatible for Intel Mount Evans SoC
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
spi-dw-add-compatible-for-intel-mount-evans-soc.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5c7b90ce00cd6f8e21d963c6fe6d85aec915540e
Author: Abe Kohandel <abe.kohandel@xxxxxxxxx>
Date: Tue Jun 6 07:54:01 2023 -0700
spi: dw: Add compatible for Intel Mount Evans SoC
[ Upstream commit 0760d5d0e9f0c0e2200a0323a61d1995bb745dee ]
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@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230606145402.474866-2-abe.kohandel@xxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
index 15f5e9cb54ad4..5a38cb09a650d 100644
--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -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},
