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soc/intel/cmn/blk/fast_spi: Cancel DMA transfer before locking

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This commit addresses a potential low power state over-consumption
issue. This issue could arise if SPI DMA has been locked down while a
transfer was still marked as active, typically if a SPI DMA transfer
failed and hung.

The fast_spi_dma_lock() function now checks if a DMA transfer is ongoing
and ensures that it is marked as complete before locking the DMA control
register.

Change-Id: I5e08991b2160a43013b129d302c46fc229f2286d
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88913
Reviewed-by: Zhixing Ma <zhixing.ma@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Bora Guvendik <bora.guvendik@intel.com>
This commit is contained in:
Jeremy Compostella 2025-08-22 16:52:08 -07:00 • committed by Matt DeVillier
commit ef0c650edf
1 changed files with 13 additions and 0 deletions
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13
src/soc/intel/common/block/fast_spi/fast_spi_dma.c
View file

@ -516,6 +516,19 @@ static void fast_spi_dma_lock(void *unused)
if (control.fields.lock)
return;
/* Ensure that any ongoing DMA transfer is marked as complete before locking. */
if (control.fields.start) {
union fast_spi_dma_status status = {fast_spi_read(FAST_SPI_DMA_STATUS)};
if (!status.fields.complete) {
status.data = 0;
status.fields.complete = 1;
fast_spi_write(FAST_SPI_DMA_STATUS, status.data);
}
control.fields.start = 0;
fast_spi_write(FAST_SPI_DMA_CONTROL, control.data);
}
control.fields.lock = 1;
fast_spi_write(FAST_SPI_DMA_CONTROL, control.data);