[PATCH v1] dmaengine: tegra: Use relaxed versions of readl/writel

Dmitry Osipenko
2019-04-24T23:18:29Z

The readl/writel functions are inserting memory barrier in order to
ensure that memory stores are completed. On Tegra20 and Tegra30 this
results in L2 cache syncing which isn't a cheapest operation. The
tegra20-apb-dma driver doesn't need to synchronize generic memory
accesses, hence use the relaxed versions of the functions.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/dma/tegra20-apb-dma.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index cf462b1abc0b..e646e1c7b299 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -241,23 +241,23 @@ struct tegra_dma {

static inline void tdma_write(struct tegra_dma *tdma, u32 reg, u32 val)
{
- writel(val, tdma->base_addr + reg);
+ writel_relaxed(val, tdma->base_addr + reg);
}

static inline u32 tdma_read(struct tegra_dma *tdma, u32 reg)
{
- return readl(tdma->base_addr + reg);
+ return readl_relaxed(tdma->base_addr + reg);
}

static inline void tdc_write(struct tegra_dma_channel *tdc,
u32 reg, u32 val)
{
- writel(val, tdc->chan_addr + reg);
+ writel_relaxed(val, tdc->chan_addr + reg);
}

static inline u32 tdc_read(struct tegra_dma_channel *tdc, u32 reg)
{
- return readl(tdc->chan_addr + reg);
+ return readl_relaxed(tdc->chan_addr + reg);
}

static inline struct tegra_dma_channel *to_tegra_dma_chan(struct dma_chan *dc)
--
2.21.0