[RFC PATCH v2] drm/komeda: fixing of DMA mapping sg segment warning

From: Lowry Li (Arm Technology China)
Date: Thu Apr 04 2019 - 06:08:11 EST


Fixing the DMA mapping sg segment warning, which shows "DMA-API: mapping
sg segment longer than device claims to support [len=921600] [max=65536]".
Fixed by setting the max segment size at Komeda driver.

This patch depends on:
- https://patchwork.freedesktop.org/series/54448/
- https://patchwork.freedesktop.org/series/54449/
- https://patchwork.freedesktop.org/series/54450/
- https://patchwork.freedesktop.org/series/58976/

Changes since v1:
- Adds member description
- Adds patch denpendency in the comment

Signed-off-by: Lowry Li (Arm Technology China) <lowry.li@xxxxxxx>
---
drivers/gpu/drm/arm/display/komeda/komeda_dev.c | 4 ++++
drivers/gpu/drm/arm/display/komeda/komeda_dev.h | 2 ++
2 files changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_dev.c b/drivers/gpu/drm/arm/display/komeda/komeda_dev.c
index 7f25e6a..b4902ae 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_dev.c
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_dev.c
@@ -8,6 +8,7 @@
#include <linux/of_device.h>
#include <linux/of_graph.h>
#include <linux/platform_device.h>
+#include <linux/dma-iommu.h>
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>
#include <linux/seq_file.h>
@@ -245,6 +246,9 @@ struct komeda_dev *komeda_dev_create(struct device *dev)
goto err_cleanup;
}

+ dev->dma_parms = &mdev->dma_parms;
+ dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
+
err = sysfs_create_group(&dev->kobj, &komeda_sysfs_attr_group);
if (err) {
DRM_ERROR("create sysfs group failed.\n");
diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_dev.h b/drivers/gpu/drm/arm/display/komeda/komeda_dev.h
index 29e03c4..83ace71 100644
--- a/drivers/gpu/drm/arm/display/komeda/komeda_dev.h
+++ b/drivers/gpu/drm/arm/display/komeda/komeda_dev.h
@@ -149,6 +149,8 @@ struct komeda_dev {
struct device *dev;
/** @reg_base: the base address of komeda io space */
u32 __iomem *reg_base;
+ /** @dma_parms: the dma parameters of komeda */
+ struct device_dma_parameters dma_parms;

/** @chip: the basic chip information */
struct komeda_chip_info chip;
--
1.9.1