[PATCH 6.4 729/800] mmc: sdhci: fix DMA configure compatibility issue when 64bit DMA mode is used.

Greg Kroah-Hartman
2023-07-16T20:28:25Z

From: Chevron Li <chevron.li@bayhubtech.com>

commit 20dbd07ef0a8bc29eb03d6a95258ac8934cbe52d upstream.

Bayhub SD host has hardware limitation:
1.The upper 32bit address is inhibited to be written at SD Host Register
[03E][13]=0 (32bits addressing) mode, is admitted to be written only at
SD Host Register [03E][13]=1 (64bits addressing) mode.
2.Because of above item#1, need to configure SD Host Register [03E][13] to
1(64bits addressing mode) before set 64bit ADMA system address's higher
32bits SD Host Register [05F~05C] if 64 bits addressing mode is used.

The hardware limitation is reasonable for below reasons:
1.Normal flow should set DMA working mode first, then do
DMA-transfer-related configuration, such as system address.
2.The hardware limitation may avoid the software to configure wrong higher
32bit address at 32bits addressing mode although it is redundant.

The change that set 32bits/64bits addressing mode before set ADMA address,
has no side-effect to other host IPs for below reason:
The setting order is reasonable and standard: DMA Mode setting first and
then DMA address setting. It meets all DMA setting sequence.

Signed-off-by: Chevron Li <chevron.li@bayhubtech.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230523111114.18124-1-chevron_li@126.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/mmc/host/sdhci.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1167,6 +1167,8 @@ static void sdhci_prepare_data(struct sd
}
}

+ sdhci_config_dma(host);
+
if (host->flags & SDHCI_REQ_USE_DMA) {
int sg_cnt = sdhci_pre_dma_transfer(host, data, COOKIE_MAPPED);

@@ -1186,8 +1188,6 @@ static void sdhci_prepare_data(struct sd
}
}

- sdhci_config_dma(host);
-
if (!(host->flags & SDHCI_REQ_USE_DMA)) {
int flags;