dmaengine: imx-sdma: add clock ratio 1:1 check

On i.mx8 mscale B0 chip, AHB/SDMA clock ratio 2:1 can't be supportted,
since SDMA clock ratio has to be increased to 250Mhz, AHB can't reach
to 500Mhz, so use 1:1 instead.

Based on NXP commit MLK-16841-1 by Robin Gong <yibin.gong@nxp.com>
Signed-off-by: 's avatarAngus Ainslie (Purism) <angus@akkea.ca>
Reviewed-by: 's avatarLucas Stach <l.stach@pengutronix.de>
parent b2f2b911
......@@ -440,6 +440,8 @@ struct sdma_engine {
unsigned int irq;
dma_addr_t bd0_phys;
struct sdma_buffer_descriptor *bd0;
/* clock ratio for AHB:SDMA core. 1:1 is 1, 2:1 is 0*/
bool clk_ratio;
};
static int sdma_config_write(struct dma_chan *chan,
......@@ -662,8 +664,11 @@ static int sdma_run_channel0(struct sdma_engine *sdma)
dev_err(sdma->dev, "Timeout waiting for CH0 ready\n");
/* Set bits of CONFIG register with dynamic context switching */
if (readl(sdma->regs + SDMA_H_CONFIG) == 0)
writel_relaxed(SDMA_H_CONFIG_CSM, sdma->regs + SDMA_H_CONFIG);
reg = readl(sdma->regs + SDMA_H_CONFIG);
if ((reg & SDMA_H_CONFIG_CSM) == 0) {
reg |= SDMA_H_CONFIG_CSM;
writel_relaxed(reg, sdma->regs + SDMA_H_CONFIG);
}
return ret;
}
......@@ -1840,6 +1845,9 @@ static int sdma_init(struct sdma_engine *sdma)
if (ret)
goto disable_clk_ipg;
if (clk_get_rate(sdma->clk_ahb) == clk_get_rate(sdma->clk_ipg))
sdma->clk_ratio = 1;
/* Be sure SDMA has not started yet */
writel_relaxed(0, sdma->regs + SDMA_H_C0PTR);
......@@ -1880,8 +1888,10 @@ static int sdma_init(struct sdma_engine *sdma)
writel_relaxed(0x4050, sdma->regs + SDMA_CHN0ADDR);
/* Set bits of CONFIG register but with static context switching */
/* FIXME: Check whether to set ACR bit depending on clock ratios */
writel_relaxed(0, sdma->regs + SDMA_H_CONFIG);
if (sdma->clk_ratio)
writel_relaxed(SDMA_H_CONFIG_ACR, sdma->regs + SDMA_H_CONFIG);
else
writel_relaxed(0, sdma->regs + SDMA_H_CONFIG);
writel_relaxed(ccb_phys, sdma->regs + SDMA_H_C0PTR);
......
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