Thread (1 message) 1 message, 1 author, 2021-09-06

Re: [PATCH v3] mmc: mediatek: add wait dma stop done flow

From: Ulf Hansson <hidden>
Date: 2021-09-06 17:10:36
Also in: linux-arm-kernel, linux-mmc, lkml

On Fri, 27 Aug 2021 at 09:15, Derong Liu [off-list ref] wrote:
We found this issue on a 5G platform, during CMDQ error handling, if DMA status is active when it call msdc_reset_hw, it means mmc host hw reset and DMA transfer will be parallel, mmc host may access sram region unexpectedly.
According to the programming guide of mtk mmc host, it needs to wait for dma stop done after set dma stop.
This change should be applied to all SoCs.

Change-Id: I9b87523f19b24ca73958bbcb83bb418413c5a180
I am dropping this tag.
Signed-off-by: Derong Liu <redacted>
Applied for next, thanks! I guess we should also tag this for stable
kernels, right?

Kind regards
Uffe

quoted hunk
---
 drivers/mmc/host/mtk-sd.c | 5 +++++
 1 file changed, 5 insertions(+)
diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
index 4dfc246c5f95..b99330bad6a5 100644
--- a/drivers/mmc/host/mtk-sd.c
+++ b/drivers/mmc/host/mtk-sd.c
@@ -8,6 +8,7 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/dma-mapping.h>
+#include <linux/iopoll.h>
 #include <linux/ioport.h>
 #include <linux/irq.h>
 #include <linux/of_address.h>
@@ -2330,6 +2331,7 @@ static void msdc_cqe_enable(struct mmc_host *mmc)
 static void msdc_cqe_disable(struct mmc_host *mmc, bool recovery)
 {
        struct msdc_host *host = mmc_priv(mmc);
+       unsigned int val = 0;

        /* disable cmdq irq */
        sdr_clr_bits(host->base + MSDC_INTEN, MSDC_INT_CMDQ);
@@ -2339,6 +2341,9 @@ static void msdc_cqe_disable(struct mmc_host *mmc, bool recovery)
        if (recovery) {
                sdr_set_field(host->base + MSDC_DMA_CTRL,
                              MSDC_DMA_CTRL_STOP, 1);
+               if (WARN_ON(readl_poll_timeout(host->base + MSDC_DMA_CFG, val,
+                       !(val & MSDC_DMA_CFG_STS), 1, 3000)))
+                       return;
                msdc_reset_hw(host);
        }
 }
--
2.18.0
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