[PATCH] Revert "mmc: dw_mmc: Fix IDMAC operation with pages bigger than 4K"

[Aurelien Jarno <aurelien@aurel32.net>]

The commit 8396c793ffdf ("mmc: dw_mmc: Fix IDMAC operation with pages
bigger than 4K") increased the max_req_size, even for 4K pages, causing
various issues:
- Panic booting the kernel/rootfs from an SD card on Rockchip RK3566
- Panic booting the kernel/rootfs from an SD card on StarFive JH7100
- "swiotlb buffer is full" and data corruption on StarFive JH7110

At this stage no fix have been found, so it's probably better to just
revert the change.

This reverts commit 8396c793ffdf28bb8aee7cfe0891080f8cab7890.

Cc: stable@vger.kernel.org
Cc: Sam Protsenko <semen.protsenko@linaro.org>
Fixes: 8396c793ffdf ("mmc: dw_mmc: Fix IDMAC operation with pages bigger than 4K")
Closes: https://lore.kernel.org/linux-mmc/614692b4-1dbe-31b8-a34d-cb6db1909bb7@w6rz.net/
Closes: https://lore.kernel.org/linux-mmc/CAC8uq=Ppnmv98mpa1CrWLawWoPnu5abtU69v-=G-P7ysATQ2Pw@mail.gmail.com/
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
---
 drivers/mmc/host/dw_mmc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

I have posted a patch to fix the issue, but unfortunately it only fixes
the JH7110 case:
https://lore.kernel.org/linux-mmc/20241020142931.138277-1-aurelien@aurel32.net/

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 41e451235f637..e9f6e4e622901 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -2957,8 +2957,8 @@ static int dw_mci_init_slot(struct dw_mci *host)
 	if (host->use_dma == TRANS_MODE_IDMAC) {
 		mmc->max_segs = host->ring_size;
 		mmc->max_blk_size = 65535;
-		mmc->max_req_size = DW_MCI_DESC_DATA_LENGTH * host->ring_size;
-		mmc->max_seg_size = mmc->max_req_size;
+		mmc->max_seg_size = 0x1000;
+		mmc->max_req_size = mmc->max_seg_size * host->ring_size;
 		mmc->max_blk_count = mmc->max_req_size / 512;
 	} else if (host->use_dma == TRANS_MODE_EDMAC) {
 		mmc->max_segs = 64;
-- 
2.45.2