From: Thierry Reding <treding@xxxxxxxxxx>
The DPAUX read/write FIFO registers aren't sequential in the register
space, causing transfers larger than 4 bytes to cause accesses to non-
existing FIFO registers.
Fixes: 6b6b604215c6 ("drm/tegra: Add eDP support")
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
---
drivers/gpu/drm/tegra/dpaux.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/tegra/dpaux.c b/drivers/gpu/drm/tegra/dpaux.c
index d6b55e3e3716..a43a836e6f88 100644
--- a/drivers/gpu/drm/tegra/dpaux.c
+++ b/drivers/gpu/drm/tegra/dpaux.c
@@ -72,34 +72,32 @@ static inline void tegra_dpaux_writel(struct tegra_dpaux *dpaux,
static void tegra_dpaux_write_fifo(struct tegra_dpaux *dpaux, const u8 *buffer,
size_t size)
{
- unsigned long offset = DPAUX_DP_AUXDATA_WRITE(0);
size_t i, j;
- for (i = 0; i < size; i += 4) {
- size_t num = min_t(size_t, size - i, 4);
+ for (i = 0; i < DIV_ROUND_UP(size, 4); i++) {
+ size_t num = min_t(size_t, size - i * 4, 4);
unsigned long value = 0;
for (j = 0; j < num; j++)
- value |= buffer[i + j] << (j * 8);
+ value |= buffer[i * 4 + j] << (j * 8);
- tegra_dpaux_writel(dpaux, value, offset++);
+ tegra_dpaux_writel(dpaux, value, DPAUX_DP_AUXDATA_WRITE(i));
}
}
static void tegra_dpaux_read_fifo(struct tegra_dpaux *dpaux, u8 *buffer,
size_t size)
{
- unsigned long offset = DPAUX_DP_AUXDATA_READ(0);
size_t i, j;
- for (i = 0; i < size; i += 4) {
- size_t num = min_t(size_t, size - i, 4);
+ for (i = 0; i < DIV_ROUND_UP(size, 4); i++) {
+ size_t num = min_t(size_t, size - i * 4, 4);
unsigned long value;
- value = tegra_dpaux_readl(dpaux, offset++);
+ value = tegra_dpaux_readl(dpaux, DPAUX_DP_AUXDATA_READ(i));
for (j = 0; j < num; j++)
- buffer[i + j] = value >> (j * 8);
+ buffer[i * 4 + j] = value >> (j * 8);
}
}
--
2.4.5
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