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793f8ab62c
Add kernel patches for version 6.1. Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
69 lines
2.4 KiB
Diff
69 lines
2.4 KiB
Diff
From 6609cb1bb479d833d11703b711cd12ade9bf8750 Mon Sep 17 00:00:00 2001
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From: Dom Cobley <popcornmix@gmail.com>
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Date: Wed, 26 Apr 2023 13:40:34 +0100
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Subject: [PATCH] bcm2835-dma: Fix dma_abort for non-40bit channels
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The sequence we were doing was not safe.
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Clearing CS meant BCM2835_DMA_WAIT_FOR_WRITES was cleared
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and so polling BCM2835_DMA_WAITING_FOR_WRITES has no benefit
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Broadcom have provided a recommended sequence to abort
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a dma lite channel, so switch to that.
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Signed-off-by: Dom Cobley <popcornmix@gmail.com>
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---
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drivers/dma/bcm2835-dma.c | 31 +++++++++++++++++++++++++++----
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1 file changed, 27 insertions(+), 4 deletions(-)
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--- a/drivers/dma/bcm2835-dma.c
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+++ b/drivers/dma/bcm2835-dma.c
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@@ -675,10 +675,18 @@ static void bcm2835_dma_abort(struct bcm
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writel(0, chan_base + BCM2711_DMA40_CS);
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writel(0, chan_base + BCM2711_DMA40_CB);
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} else {
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+ /*
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+ * A zero control block address means the channel is idle.
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+ * (The ACTIVE flag in the CS register is not a reliable indicator.)
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+ */
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+ if (!readl(chan_base + BCM2835_DMA_ADDR))
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+ return;
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+
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/* Write 0 to the active bit - Pause the DMA */
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- writel(0, chan_base + BCM2835_DMA_CS);
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+ writel(readl(chan_base + BCM2835_DMA_CS) & ~BCM2835_DMA_ACTIVE,
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+ chan_base + BCM2835_DMA_CS);
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- /* Wait for any current AXI transfer to complete */
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+ /* wait for DMA to be paused */
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while ((readl(chan_base + BCM2835_DMA_CS) & BCM2835_DMA_WAITING_FOR_WRITES)
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&& --timeout)
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cpu_relax();
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@@ -686,9 +694,24 @@ static void bcm2835_dma_abort(struct bcm
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/* Peripheral might be stuck and fail to signal AXI write responses */
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if (!timeout)
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dev_err(c->vc.chan.device->dev,
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- "failed to complete outstanding writes\n");
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+ "failed to pause dma\n");
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+
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+ /* We need to clear the next DMA block pending */
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+ writel(0, chan_base + BCM2835_DMA_NEXTCB);
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+
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+ /* Abort the DMA, which needs to be enabled to complete */
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+ writel(readl(chan_base + BCM2835_DMA_CS) | BCM2835_DMA_ABORT | BCM2835_DMA_ACTIVE,
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+ chan_base + BCM2835_DMA_CS);
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+
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+ /* wait for DMA to have been aborted */
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+ timeout = 10000;
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+ while ((readl(chan_base + BCM2835_DMA_CS) & BCM2835_DMA_ABORT) && --timeout)
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+ cpu_relax();
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- writel(BCM2835_DMA_RESET, chan_base + BCM2835_DMA_CS);
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+ /* Peripheral might be stuck and fail to signal AXI write responses */
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+ if (!timeout)
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+ dev_err(c->vc.chan.device->dev,
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+ "failed to abort dma\n");
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}
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}
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