From 27a5e7d36d383970affae801d77141deafd536a8 Mon Sep 17 00:00:00 2001
From: Neil Armstrong <narmstrong@baylibre.com>
Date: Mon, 8 Jun 2020 10:44:58 +0200
Subject: [PATCH] mmc: meson-gx: limit segments to 1 when dram-access-quirk is needed
Git-commit: 27a5e7d36d383970affae801d77141deafd536a8
Patch-mainline: v5.8-rc5
References: git-fixes
The actual max_segs computation leads to failure while using the broadcom
sdio brcmfmac/bcmsdh driver, since the driver tries to make usage of
scatter gather.
But with the dram-access-quirk we use a 1,5K SRAM bounce buffer, and the
max_segs current value of 3 leads to max transfers to 4,5k, which doesn't
work.
This patch sets max_segs to 1 to better describe the hardware limitation,
and fix the SDIO functionality with the brcmfmac/bcmsdh driver on Amlogic
G12A/G12B SoCs on boards like SEI510 or Khadas VIM3.
Reported-by: Art Nikpal <art@khadas.com>
Reported-by: Christian Hewitt <christianshewitt@gmail.com>
Fixes: acdc8e71d9bb ("mmc: meson-gx: add dram-access-quirk")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200608084458.32014-1-narmstrong@baylibre.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/mmc/host/meson-gx-mmc.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index 7eb38d7482c6..08a3b1c05acb 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -1146,9 +1146,11 @@ static int meson_mmc_probe(struct platform_device *pdev)
mmc->caps |= MMC_CAP_CMD23;
if (host->dram_access_quirk) {
+ /* Limit segments to 1 due to low available sram memory */
+ mmc->max_segs = 1;
/* Limit to the available sram memory */
- mmc->max_segs = SD_EMMC_SRAM_DATA_BUF_LEN / mmc->max_blk_size;
- mmc->max_blk_count = mmc->max_segs;
+ mmc->max_blk_count = SD_EMMC_SRAM_DATA_BUF_LEN /
+ mmc->max_blk_size;
} else {
mmc->max_blk_count = CMD_CFG_LENGTH_MASK;
mmc->max_segs = SD_EMMC_DESC_BUF_LEN /
--
2.16.4