blob: 5c26f3be4ef0d28e86a8878758ced2a14d98c3c6 [file] [log] [blame]
From c199b1da50378f7affda84f07a8d56108b0a4f41 Mon Sep 17 00:00:00 2001
From: Ludovic Barre <>
Date: Tue, 26 May 2020 17:51:02 +0200
Subject: [PATCH] mmc: mmci_sdmmc: fix DMA API warning overlapping mappings
commit fe8d33bd33d527dee3155d2bccd714a655f37334 upstream.
Turning on CONFIG_DMA_API_DEBUG_SG results in the following warning:
WARNING: CPU: 1 PID: 20 at kernel/dma/debug.c:500 add_dma_entry+0x16c/0x17c
DMA-API: exceeded 7 overlapping mappings of cacheline 0x031d2645
Modules linked in:
CPU: 1 PID: 20 Comm: kworker/1:1 Not tainted 5.5.0-rc2-00021-gdeda30999c2b-dirty #49
Hardware name: STM32 (Device Tree Support)
Workqueue: events_freezable mmc_rescan
[<c03138c0>] (unwind_backtrace) from [<c030d760>] (show_stack+0x10/0x14)
[<c030d760>] (show_stack) from [<c0f2eb28>] (dump_stack+0xc0/0xd4)
[<c0f2eb28>] (dump_stack) from [<c034a14c>] (__warn+0xd0/0xf8)
[<c034a14c>] (__warn) from [<c034a530>] (warn_slowpath_fmt+0x94/0xb8)
[<c034a530>] (warn_slowpath_fmt) from [<c03bca0c>] (add_dma_entry+0x16c/0x17c)
[<c03bca0c>] (add_dma_entry) from [<c03bdf54>] (debug_dma_map_sg+0xe4/0x3d4)
[<c03bdf54>] (debug_dma_map_sg) from [<c0d09244>] (sdmmc_idma_prep_data+0x94/0xf8)
[<c0d09244>] (sdmmc_idma_prep_data) from [<c0d05a2c>] (mmci_prep_data+0x2c/0xb0)
[<c0d05a2c>] (mmci_prep_data) from [<c0d073ec>] (mmci_start_data+0x134/0x2f0)
[<c0d073ec>] (mmci_start_data) from [<c0d078d0>] (mmci_request+0xe8/0x154)
[<c0d078d0>] (mmci_request) from [<c0cecb44>] (mmc_start_request+0x94/0xbc)
DMA api debug brings to light leaking dma-mappings, dma_map_sg and
dma_unmap_sg are not correctly balanced.
If a request is prepared, the dma_map/unmap are done in asynchronous call
pre_req (prep_data) and post_req (unprep_data). In this case the
dma-mapping is right balanced.
But if the request was not prepared, the data->host_cookie is define to
zero and the dma_map/unmap must be done in the request. The dma_map is
called by mmci_dma_start (prep_data), but there is no dma_unmap in this
This patch adds dma_unmap_sg when the dma is finalized and the data cookie
is zero (request not prepared).
Signed-off-by: Ludovic Barre <>
Fixes: 46b723dd867d ("mmc: mmci: add stm32 sdmmc variant")
Signed-off-by: Ulf Hansson <>
Signed-off-by: Paul Gortmaker <>
diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
index 8e83ae6920ae..0953bd8a4f79 100644
--- a/drivers/mmc/host/mmci_stm32_sdmmc.c
+++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
@@ -162,6 +162,9 @@ static int sdmmc_idma_start(struct mmci_host *host, unsigned int *datactrl)
static void sdmmc_idma_finalize(struct mmci_host *host, struct mmc_data *data)
writel_relaxed(0, host->base + MMCI_STM32_IDMACTRLR);
+ if (!data->host_cookie)
+ sdmmc_idma_unprep_data(host, data, 0);
static void mmci_sdmmc_set_clkreg(struct mmci_host *host, unsigned int desired)