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mmc: mmci: use peripheral flow control for STM32

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The STM32 SDMMC peripheral (at least for the STM32F429, STM32F469 and
STM32F746, which are all the currently supported devices using periphid
0x00880180) requires DMA to be performed in peripheral flow controller
mode. From the STM32F74/5 reference manual, section 35.3.2:

"SDMMC host allows only to use the DMA in peripheral flow controller
mode. DMA stream used to serve SDMMC must be configured in peripheral
flow controller mode"

This patch adds a variant option to control peripheral flow control and
enables it for the STM32 variant.

Signed-off-by: Ben Wolsieffer <Ben.Wolsieffer@hefring.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20230928135644.1489691-1-ben.wolsieffer@hefring.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Ben Wolsieffer 2023-09-28 09:56:44 -04:00 committed by Ulf Hansson
parent 09b5982971
commit 44ac5e9158
2 changed files with 4 additions and 1 deletions
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3
drivers/mmc/host/mmci.c
View file

@ -249,6 +249,7 @@ static struct variant_data variant_stm32 = {
.f_max = 48000000,
.pwrreg_clkgate = true,
.pwrreg_nopower = true,
.dma_flow_controller = true,
.init = mmci_variant_init,
};
@ -1015,7 +1016,7 @@ static int _mmci_dmae_prep_data(struct mmci_host *host, struct mmc_data *data,
.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
.src_maxburst = variant->fifohalfsize >> 2, /* # of words */
.dst_maxburst = variant->fifohalfsize >> 2, /* # of words */
.device_fc = false,
.device_fc = variant->dma_flow_controller,
};
struct dma_chan *chan;
struct dma_device *device;

2
drivers/mmc/host/mmci.h
View file

@ -332,6 +332,7 @@ enum mmci_busy_state {
* @opendrain: bitmask identifying the OPENDRAIN bit inside MMCIPOWER register
* @dma_lli: true if variant has dma link list feature.
* @stm32_idmabsize_mask: stm32 sdmmc idma buffer size.
* @dma_flow_controller: use peripheral as flow controller for DMA.
*/
struct variant_data {
unsigned int clkreg;
@ -378,6 +379,7 @@ struct variant_data {
u8 dma_lli:1;
u32 stm32_idmabsize_mask;
u32 stm32_idmabsize_align;
bool dma_flow_controller;
void (*init)(struct mmci_host *host);
};