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From: Christophe Kerello <christophe.kerello@foss.st.com>
To: <ulf.hansson@linaro.org>, <alexandre.torgue@foss.st.com>,
        <yann.gautier@foss.st.com>, <linus.walleij@linaro.org>
CC: <linux-mmc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        Christophe Kerello
	<christophe.kerello@foss.st.com>
Subject: [PATCH] mmc: mmci: stm32: fix DMA API overlapping mappings warning
Date: Wed, 7 Feb 2024 15:39:51 +0100
Message-ID: <20240207143951.938144-1-christophe.kerello@foss.st.com>
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Turning on CONFIG_DMA_API_DEBUG_SG results in the following warning:

DMA-API: mmci-pl18x 48220000.mmc: cacheline tracking EEXIST,
overlapping mappings aren't supported
WARNING: CPU: 1 PID: 51 at kernel/dma/debug.c:568
add_dma_entry+0x234/0x2f4
Modules linked in:
CPU: 1 PID: 51 Comm: kworker/1:2 Not tainted 6.1.28 #1
Hardware name: STMicroelectronics STM32MP257F-EV1 Evaluation Board (DT)
Workqueue: events_freezable mmc_rescan
Call trace:
add_dma_entry+0x234/0x2f4
debug_dma_map_sg+0x198/0x350
__dma_map_sg_attrs+0xa0/0x110
dma_map_sg_attrs+0x10/0x2c
sdmmc_idma_prep_data+0x80/0xc0
mmci_prep_data+0x38/0x84
mmci_start_data+0x108/0x2dc
mmci_request+0xe4/0x190
__mmc_start_request+0x68/0x140
mmc_start_request+0x94/0xc0
mmc_wait_for_req+0x70/0x100
mmc_send_tuning+0x108/0x1ac
sdmmc_execute_tuning+0x14c/0x210
mmc_execute_tuning+0x48/0xec
mmc_sd_init_uhs_card.part.0+0x208/0x464
mmc_sd_init_card+0x318/0x89c
mmc_attach_sd+0xe4/0x180
mmc_rescan+0x244/0x320

DMA API debug brings to light leaking dma-mappings as dma_map_sg and
dma_unmap_sg are not correctly balanced.

If an error occurs in mmci_cmd_irq function, only mmci_dma_error
function is called and as this API is not managed on stm32 variant,
dma_unmap_sg is never called in this error path.

Signed-off-by: Christophe Kerello <christophe.kerello@foss.st.com>
---
 drivers/mmc/host/mmci_stm32_sdmmc.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
index 35067e1e6cd8..f5da7f9baa52 100644
--- a/drivers/mmc/host/mmci_stm32_sdmmc.c
+++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
@@ -225,6 +225,8 @@ static int sdmmc_idma_start(struct mmci_host *host, unsigned int *datactrl)
 	struct scatterlist *sg;
 	int i;
 
+	host->dma_in_progress = true;
+
 	if (!host->variant->dma_lli || data->sg_len == 1 ||
 	    idma->use_bounce_buffer) {
 		u32 dma_addr;
@@ -263,9 +265,30 @@ static int sdmmc_idma_start(struct mmci_host *host, unsigned int *datactrl)
 	return 0;
 }
 
+static void sdmmc_idma_error(struct mmci_host *host)
+{
+	struct mmc_data *data = host->data;
+	struct sdmmc_idma *idma = host->dma_priv;
+
+	if (!dma_inprogress(host))
+		return;
+
+	writel_relaxed(0, host->base + MMCI_STM32_IDMACTRLR);
+	host->dma_in_progress = false;
+	data->host_cookie = 0;
+
+	if (!idma->use_bounce_buffer)
+		dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
+			     mmc_get_dma_dir(data));
+}
+
 static void sdmmc_idma_finalize(struct mmci_host *host, struct mmc_data *data)
 {
+	if (!dma_inprogress(host))
+		return;
+
 	writel_relaxed(0, host->base + MMCI_STM32_IDMACTRLR);
+	host->dma_in_progress = false;
 
 	if (!data->host_cookie)
 		sdmmc_idma_unprep_data(host, data, 0);
@@ -676,6 +699,7 @@ static struct mmci_host_ops sdmmc_variant_ops = {
 	.dma_setup = sdmmc_idma_setup,
 	.dma_start = sdmmc_idma_start,
 	.dma_finalize = sdmmc_idma_finalize,
+	.dma_error = sdmmc_idma_error,
 	.set_clkreg = mmci_sdmmc_set_clkreg,
 	.set_pwrreg = mmci_sdmmc_set_pwrreg,
 	.busy_complete = sdmmc_busy_complete,
-- 
2.25.1