dmaengine: stm32-dma: check whether length is aligned on FIFO threshold (ecda0abb) · Commits · e / devices / android_kernel_oneplus_sm7250

commit cc832dc8e32785a730ba07c3a357e17c201a5df8 upstream. When a period length is not multiple of FIFO some data may be stuck within FIFO. Burst/FIFO Threshold/Period or buffer length check has to be hardened In any case DMA will grant any request from client but will degraded any parameters whether awkward. Signed-off-by:

Pierre-Yves MORDRET <pierre-yves.mordret@st.com> Signed-off-by:

Vinod Koul <vkoul@kernel.org> Signed-off-by:

Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/dma/stm32-dma.c

+6 −14

Original line number	Diff line number	Diff line
		@@ -308,20 +308,12 @@ static bool stm32_dma_fifo_threshold_is_allowed(u32 burst, u32 threshold,

		static bool stm32_dma_is_burst_possible(u32 buf_len, u32 threshold)
		{
		switch (threshold) {
		case STM32_DMA_FIFO_THRESHOLD_FULL:
		if (buf_len >= STM32_DMA_MAX_BURST)
		return true;
		else
		return false;
		case STM32_DMA_FIFO_THRESHOLD_HALFFULL:
		if (buf_len >= STM32_DMA_MAX_BURST / 2)
		return true;
		else
		return false;
		default:
		return false;
		}
		/*
		* Buffer or period length has to be aligned on FIFO depth.
		* Otherwise bytes may be stuck within FIFO at buffer or period
		* length.
		*/
		return ((buf_len % ((threshold + 1) * 4)) == 0);
		}

		static u32 stm32_dma_get_best_burst(u32 buf_len, u32 max_burst, u32 threshold,