linux-kernel - [PATCH 5.15 018/917] mmc: mtk-sd: Add wait dma stop done flow

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Date:   Mon, 15 Nov 2021 17:51:53 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Derong Liu <derong.liu@...iatek.com>,
        Ulf Hansson <ulf.hansson@...aro.org>
Subject: [PATCH 5.15 018/917] mmc: mtk-sd: Add wait dma stop done flow

From: Derong Liu <derong.liu@...iatek.com>

commit 43e5fee317f4b0a48992b8b07935b1a3ac20ce84 upstream.

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-sd host, it needs
to wait for dma stop done after set dma stop.

This change should be applied to all SoCs.

Signed-off-by: Derong Liu <derong.liu@...iatek.com>
Cc: stable@...r.kernel.org
Link: https://lore.kernel.org/r/20210827071537.1034-1-derong.liu@mediatek.com
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/mmc/host/mtk-sd.c |    5 +++++
 1 file changed, 5 insertions(+)

--- 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_h
 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_
 	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);
 	}
 }