@@ -629,7 +629,7 @@ static int dw_spi_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
* operation. Transmit-only mode is suitable for the rest of them.
*/
cfg.dfs = 8;
- cfg.freq = mem->spi->max_speed_hz;
+ cfg.freq = clamp(mem->spi->max_speed_hz, 0U, dws->max_mem_freq);
if (op->data.dir == SPI_MEM_DATA_IN) {
cfg.tmode = SPI_TMOD_EPROMREAD;
cfg.ndf = op->data.nbytes;
@@ -716,6 +716,8 @@ static void dw_spi_init_mem_ops(struct dw_spi *dws)
dws->mem_ops.adjust_op_size = dw_spi_adjust_mem_op_size;
dws->mem_ops.supports_op = dw_spi_supports_mem_op;
dws->mem_ops.exec_op = dw_spi_exec_mem_op;
+ if (!dws->max_mem_freq)
+ dws->max_mem_freq = dws->max_freq;
}
}
@@ -148,6 +148,7 @@ struct dw_spi {
unsigned long paddr;
int irq;
u32 fifo_len; /* depth of the FIFO buffer */
+ u32 max_mem_freq; /* max mem-ops bus freq */
u32 max_freq; /* max bus freq supported */
u32 caps; /* DW SPI capabilities */
In some circumstances the current implementation of the SPI memory operations may occasionally fail even though they are executed in the atomic context. This may happen if the system bus is relatively slow in comparison to the SPI bus frequency, or there is a concurrent access to it, which makes the MMIO-operations occasionally stalling before push-pulling data from the DW APB SPI FIFOs. These two problems we've discovered on the Baikal-T1 SoC. In order to fix them we have no choice but to set an artificial limitation on the SPI bus speed. Note currently this limitation will be only applicable for the memory operations, since the standard SPI core interface is implemented with an assumption that there is no problem with the automatic CS toggling. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> --- drivers/spi/spi-dw-core.c | 4 +++- drivers/spi/spi-dw.h | 1 + 2 files changed, 4 insertions(+), 1 deletion(-)