Integrate meta-seco-imx/linux-seco-imx/niccolor/sdma-hang-during-boot
Integrate linux-seco-imx/niccolor/sdma-hang-during-boot
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[PATCH] LF-5352: dmaengine: imx-sdma: fix the potential access registers without clock
The issue can be triggered with the sdma pm_runtime false.
If the dma client try to use sdma in boot phase, it may cause system hang. The sdma driver really enable clk after sdma load firmware, the clk_disable_unused will disable the SDMA1_ROOT_CLK before the sdma driver enable clk. This issue will comes if access the sdma register when the SDMA1_ROOT_CLK is disable.
This issue is very easy to reproduce with hdmi connected displayer on imx7d-sbd board which the i2c will use sdma early before sdma firmware loaded and clock enabled.
The client i2c calls dmaengine_prep_slave_single->device_prep_slave_sg ->sdma_prep_slave_sg->sdma_config_write->sdma_config_channel to get descriptor in boot phase. Then, the function sdma_config_channel will access sdma registers. If clk is disable will cause system hang.
This patch adds clk_enable and clk_disable to make sure the clk enable before access sdma hardware.
Signed-off-by: Joy Zou joy.zou@nxp.com Reviewed-by: Shengjiu Wang shengjiu.wang@nxp.com Reviewed-by: Dong Aisheng aisheng.dong@nxp.com Acked-by: Jason Liu jason.hui.liu@nxp.com