[PATCH 4.19 150/220] mmc: renesas_sdhi_internal_dmac: set scatter/gather max segment size

From: Greg Kroah-Hartman
Date: Fri Nov 22 2019 - 06:02:56 EST

From: Niklas SÃderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>

[ Upstream commit 54541815b43f4e49c82628bf28bbb31d86d2f58a ]

Fix warning when running with CONFIG_DMA_API_DEBUG_SG=y by allocating a
device_dma_parameters structure and filling in the max segment size. The
size used is the result of a discussion with Renesas hardware engineers
and unfortunately not found in the datasheet.

renesas_sdhi_internal_dmac ee140000.sd: DMA-API: mapping sg segment
longer than device claims to support [len=126976] [max=65536]

Reported-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Signed-off-by: Niklas SÃderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
[wsa: simplified some logic after validating intended dma_parms life cycle
and added comment]
Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/mmc/host/renesas_sdhi_internal_dmac.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/mmc/host/renesas_sdhi_internal_dmac.c b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
index f4aefa8954bfc..382172fb3da8f 100644
--- a/drivers/mmc/host/renesas_sdhi_internal_dmac.c
+++ b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
@@ -310,12 +310,20 @@ static const struct soc_device_attribute gen3_soc_whitelist[] = {
static int renesas_sdhi_internal_dmac_probe(struct platform_device *pdev)
const struct soc_device_attribute *soc = soc_device_match(gen3_soc_whitelist);
+ struct device *dev = &pdev->dev;

if (!soc)
return -ENODEV;

global_flags |= (unsigned long)soc->data;

+ dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms), GFP_KERNEL);
+ if (!dev->dma_parms)
+ return -ENOMEM;
+ /* value is max of SD_SECCNT. Confirmed by HW engineers */
+ dma_set_max_seg_size(dev, 0xffffffff);
return renesas_sdhi_probe(pdev, &renesas_sdhi_internal_dmac_dma_ops);