From: Sonny Rao <sonnyrao@chromium.org>
To: linux-mmc@vger.kernel.org
Cc: Heiko Stuebner <heiko@sntech.de>,
Seungwon Jeon <tgih.jun@samsung.com>,
Jaehoon Chung <jh80.chung@samsung.com>,
Ulf Hansson <ulf.hansson@linaro.org>,
dianders@chromium.org, eddie.cai@rock-chips.com,
addy.ke@rock-chips.com, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Sonny Rao <sonnyrao@chromium.org>
Subject: [PATCH] mmc: dw_mmc: Reset DMA before enabling IDMAC
Date: Mon, 6 Oct 2014 10:53:40 -0700 [thread overview]
Message-ID: <1412618020-22278-1-git-send-email-sonnyrao@chromium.org> (raw)
We've already got a reset of DMA after it's done. Add one before we
start DMA too. This fixes a data corruption on Rockchip SoCs which
will get bad data when doing a DMA transfer after doing a PIO transfer.
We tested this on an Exynos 5800 with HS200 and didn't notice any
difference in sequential read throughput.
Signed-off-by: Sonny Rao <sonnyrao@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
---
drivers/mmc/host/dw_mmc.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 69f0cc6..2b5401e 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -83,6 +83,7 @@ struct idmac_desc {
#endif /* CONFIG_MMC_DW_IDMAC */
static bool dw_mci_reset(struct dw_mci *host);
+static bool dw_mci_ctrl_reset(struct dw_mci *host, u32 reset);
#if defined(CONFIG_DEBUG_FS)
static int dw_mci_req_show(struct seq_file *s, void *v)
@@ -448,6 +449,9 @@ static void dw_mci_idmac_start_dma(struct dw_mci *host, unsigned int sg_len)
dw_mci_translate_sglist(host, host->data, sg_len);
+ /* Make sure to reset DMA in case we did PIO before this */
+ dw_mci_ctrl_reset(host, SDMMC_CTRL_DMA_RESET);
+
/* Select IDMAC interface */
temp = mci_readl(host, CTRL);
temp |= SDMMC_CTRL_USE_IDMAC;
--
1.8.3.2
next reply other threads:[~2014-10-06 17:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-06 17:53 Sonny Rao [this message]
2014-10-06 18:11 ` [PATCH] mmc: dw_mmc: Reset DMA before enabling IDMAC Doug Anderson
2014-10-07 23:59 ` Jaehoon Chung
2014-10-08 11:28 ` Alim Akhtar
[not found] ` <CAO3aYcqi0g=eJta33s5oM-tAAmAhe86VvHd43p5RJ7qMPZzfrg@mail.gmail.com>
2014-10-09 22:19 ` Alim Akhtar
2014-10-10 0:36 ` Doug Anderson
2014-10-14 16:51 ` Doug Anderson
2014-10-14 19:58 ` Alim Akhtar
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