[PATCH 0/4] mmc: mmci_sdmmc: fixes and improvements

[PATCH 0/4] mmc: mmci_sdmmc: fixes and improvements

[Ludovic Barre]

This patch series fixes some problems:
-dma api debug warning to segment size check.
-dma_unmap_sg missing on not prepared request.
-Clear busyd0end irq flag when a R1B busy is completed.
-Initialize pwr|clk|datactrl_reg with their hardware values at probe.

Ludovic Barre (4):
  mmc: mmci_sdmmc: fix DMA API warning max segment size
  mmc: mmci_sdmmc: fix DMA API warning overlapping mappings
  mmc: mmci_sdmmc: fix clear busyd0end irq flag
  mmc: mmci: initialize pwr|clk|datactrl_reg with their hardware values

 drivers/mmc/host/mmci.c             |  4 ++++
 drivers/mmc/host/mmci_stm32_sdmmc.c | 21 +++++++++++++--------
 2 files changed, 17 insertions(+), 8 deletions(-)

-- 
2.17.1

[PATCH 1/4] mmc: mmci_sdmmc: fix DMA API warning max segment size

[Ludovic Barre]

Turning on CONFIG_DMA_API_DEBUG_SG results in the following warning:
WARNING: CPU: 1 PID: 85 at kernel/dma/debug.c:1302 debug_dma_map_sg+0x2a0/0x3cc
mmci-pl18x 58005000.sdmmc: DMA-API: mapping sg segment longer than device claims to support [len=126976] [max=65536]

dma api debug checks and compares the segment size to
dma_get_max_seg_size (dev->dma_parms->max_segment_size),
the sdmmc variant has an internal DMA and should define
its max_segment_size constraint to avoid this warning.

This Patch defines the dev->dma_parms->max_segment_size
with the constraint already set for mmc core
(host->mmc->max_seg_size).

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
---
 drivers/mmc/host/mmci_stm32_sdmmc.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
index f76e82f8f12f..56d9ad7f523e 100644
--- a/drivers/mmc/host/mmci_stm32_sdmmc.c
+++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
@@ -119,20 +119,20 @@ static void sdmmc_idma_unprep_data(struct mmci_host *host,
 static int sdmmc_idma_setup(struct mmci_host *host)
 {
 	struct sdmmc_idma *idma;
+	struct device *dev = mmc_dev(host->mmc);
 
-	idma = devm_kzalloc(mmc_dev(host->mmc), sizeof(*idma), GFP_KERNEL);
-	if (!idma)
+	idma = devm_kzalloc(dev, sizeof(*idma), GFP_KERNEL);
+	dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms), GFP_KERNEL);
+	if (!idma || !dev->dma_parms)
 		return -ENOMEM;
 
 	host->dma_priv = idma;
 
 	if (host->variant->dma_lli) {
-		idma->sg_cpu = dmam_alloc_coherent(mmc_dev(host->mmc),
-						   SDMMC_LLI_BUF_LEN,
+		idma->sg_cpu = dmam_alloc_coherent(dev, SDMMC_LLI_BUF_LEN,
 						   &idma->sg_dma, GFP_KERNEL);
 		if (!idma->sg_cpu) {
-			dev_err(mmc_dev(host->mmc),
-				"Failed to alloc IDMA descriptor\n");
+			dev_err(dev, "Failed to alloc IDMA descriptor\n");
 			return -ENOMEM;
 		}
 		host->mmc->max_segs = SDMMC_LLI_BUF_LEN /
@@ -143,6 +143,8 @@ static int sdmmc_idma_setup(struct mmci_host *host)
 		host->mmc->max_seg_size = host->mmc->max_req_size;
 	}
 
+	dma_set_max_seg_size(dev, host->mmc->max_seg_size);
+
 	return 0;
 }
 
-- 
2.17.1

[PATCH 2/4] mmc: mmci_sdmmc: fix DMA API warning overlapping mappings

[Ludovic Barre]

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 case.

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 <ludovic.barre@st.com>
---
 drivers/mmc/host/mmci_stm32_sdmmc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
index 56d9ad7f523e..7b781c897346 100644
--- a/drivers/mmc/host/mmci_stm32_sdmmc.c
+++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
@@ -190,6 +190,9 @@ 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)
-- 
2.17.1

[PATCH 3/4] mmc: mmci_sdmmc: fix clear busyd0end irq flag

[Ludovic Barre]

The busyd0 line transition can be very fast. The busy request
may be completed by busy_d0end without wait the busy_d0 steps.
The busyd0end irq flag must be cleared even if no busy_status.

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
---
 drivers/mmc/host/mmci_stm32_sdmmc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
index 7b781c897346..82b88293e742 100644
--- a/drivers/mmc/host/mmci_stm32_sdmmc.c
+++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
@@ -363,11 +363,11 @@ static bool sdmmc_busy_complete(struct mmci_host *host, u32 status, u32 err_msk)
 	if (host->busy_status) {
 		writel_relaxed(mask & ~host->variant->busy_detect_mask,
 			       base + MMCIMASK0);
-		writel_relaxed(host->variant->busy_detect_mask,
-			       base + MMCICLEAR);
 		host->busy_status = 0;
 	}
 
+	writel_relaxed(host->variant->busy_detect_mask, base + MMCICLEAR);
+
 	return true;
 }
 
-- 
2.17.1

[PATCH 4/4] mmc: mmci: initialize pwr|clk|datactrl_reg with their hardware values

[Ludovic Barre]

In mmci_write_pwr|clk|datactrlreg functions, if the desired value
is equal to corresponding variable (pwr_reg|clk_reg|datactrl_reg),
the value is not written in the register.

At probe pwr|clk|datactrl_reg of mmci_host structure are initialized
to 0 (kzalloc of mmc_alloc_host). But they does not necessarily reflect
hardware value of these registers, if they are used while boot level.
This is problematic, if we want to write 0 in these registers.

This patch initializes pwr|clk|datactrl_reg variables with their
hardware values while probing.

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
---
 drivers/mmc/host/mmci.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 647567def612..f378ae18d5dc 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -2085,6 +2085,10 @@ static int mmci_probe(struct amba_device *dev,
 	else if (plat->ocr_mask)
 		dev_warn(mmc_dev(mmc), "Platform OCR mask is ignored\n");
 
+	host->pwr_reg = readl_relaxed(host->base + MMCIPOWER);
+	host->clk_reg = readl_relaxed(host->base + MMCICLOCK);
+	host->datactrl_reg = readl_relaxed(host->base + MMCIDATACTRL);
+
 	/* We support these capabilities. */
 	mmc->caps |= MMC_CAP_CMD23;
 
-- 
2.17.1