linux-kernel - [PATCH AUTOSEL 4.19 139/209] mmc: renesas_sdhi_internal_dmac: set scatter/gather max segment size

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Message-Id: <20191113015025.9685-139-sashal@kernel.org>
Date:   Tue, 12 Nov 2019 20:49:15 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Niklas Söderlund 
        <niklas.soderlund+renesas@...natech.se>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Sasha Levin <sashal@...nel.org>, linux-mmc@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 139/209] mmc: renesas_sdhi_internal_dmac: set scatter/gather max segment size

From: Niklas Söderlund <niklas.soderlund+renesas@...natech.se>

[ 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@...der.be>
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@...natech.se>
[wsa: simplified some logic after validating intended dma_parms life cycle
      and added comment]
Signed-off-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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);
 }
 
-- 
2.20.1