diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.1/0165-bcm2708-dmaengine-Use-more-DMA-channels-but-not-12.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.1/0165-bcm2708-dmaengine-Use-more-DMA-channels-but-not-12.patch | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.1/0165-bcm2708-dmaengine-Use-more-DMA-channels-but-not-12.patch b/target/linux/brcm2708/patches-4.1/0165-bcm2708-dmaengine-Use-more-DMA-channels-but-not-12.patch new file mode 100644 index 0000000..a1029dc --- /dev/null +++ b/target/linux/brcm2708/patches-4.1/0165-bcm2708-dmaengine-Use-more-DMA-channels-but-not-12.patch @@ -0,0 +1,173 @@ +From 4e62a443aa8ffecca7918db93329d8bd8210a92c Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.org> +Date: Thu, 20 Aug 2015 13:50:18 +0100 +Subject: [PATCH 165/171] bcm2708-dmaengine: Use more DMA channels (but not 12) + +1) Only the bcm2708_fb drivers uses the legacy DMA API, and +it requires a BULK-capable channel, so all other types +(FAST, NORMAL and LITE) can be made available to the regular +DMA API. + +2) DMA channels 11-14 share an interrupt. The driver can't +handle this, so don't use channels 12-14 (12 was used, probably +because it appears to have an interrupt, but in reality that +interrupt is for activity on ANY channel). This may explain +a lockup encountered when running out of DMA channels. + +The combined effect of this patch is to leave 7 DMA channels +available + channel 0 for bcm2708_fb via the legacy API. + +See: https://github.com/raspberrypi/linux/issues/1110 + https://github.com/raspberrypi/linux/issues/1108 +--- + arch/arm/boot/dts/bcm2708_common.dtsi | 5 ++-- + drivers/dma/bcm2708-dmaengine.c | 43 +++++++++++++++++++++++------------ + 2 files changed, 31 insertions(+), 17 deletions(-) + +--- a/arch/arm/boot/dts/bcm2708_common.dtsi ++++ b/arch/arm/boot/dts/bcm2708_common.dtsi +@@ -59,11 +59,10 @@ + <1 24>, + <1 25>, + <1 26>, +- <1 27>, +- <1 28>; ++ <1 27>; + + #dma-cells = <1>; +- brcm,dma-channel-mask = <0x7f35>; ++ brcm,dma-channel-mask = <0x0f35>; + }; + + intc: interrupt-controller { +--- a/drivers/dma/bcm2708-dmaengine.c ++++ b/drivers/dma/bcm2708-dmaengine.c +@@ -184,7 +184,7 @@ static void vc_dmaman_init(struct vc_dma + } + + static int vc_dmaman_chan_alloc(struct vc_dmaman *dmaman, +- unsigned preferred_feature_set) ++ unsigned required_feature_set) + { + u32 chans; + int chan = 0; +@@ -193,10 +193,8 @@ static int vc_dmaman_chan_alloc(struct v + chans = dmaman->chan_available; + for (feature = 0; feature < BCM_DMA_FEATURE_COUNT; feature++) + /* select the subset of available channels with the desired +- feature so long as some of the candidate channels have that +- feature */ +- if ((preferred_feature_set & (1 << feature)) && +- (chans & dmaman->has_feature[feature])) ++ features */ ++ if (required_feature_set & (1 << feature)) + chans &= dmaman->has_feature[feature]; + + if (!chans) +@@ -228,7 +226,7 @@ static int vc_dmaman_chan_free(struct vc + + /* DMA Manager Monitor */ + +-extern int bcm_dma_chan_alloc(unsigned preferred_feature_set, ++extern int bcm_dma_chan_alloc(unsigned required_feature_set, + void __iomem **out_dma_base, int *out_dma_irq) + { + struct vc_dmaman *dmaman = g_dmaman; +@@ -240,7 +238,7 @@ extern int bcm_dma_chan_alloc(unsigned p + return -ENODEV; + + mutex_lock(&dmaman->lock); +- chan = vc_dmaman_chan_alloc(dmaman, preferred_feature_set); ++ chan = vc_dmaman_chan_alloc(dmaman, required_feature_set); + if (chan < 0) + goto out; + +@@ -442,6 +440,7 @@ static inline struct bcm2835_desc *to_bc + return container_of(t, struct bcm2835_desc, vd.tx); + } + ++#if 0 + static void dma_dumpregs(struct bcm2835_chan *c) + { + pr_debug("-------------DMA DUMPREGS-------------\n"); +@@ -457,6 +456,7 @@ static void dma_dumpregs(struct bcm2835_ + readl(c->chan_base + BCM2835_DMA_NEXTCB)); + pr_debug("--------------------------------------\n"); + } ++#endif + + static void bcm2835_dma_desc_free(struct virt_dma_desc *vd) + { +@@ -862,6 +862,7 @@ static struct dma_async_tx_descriptor *b + uint32_t len = sg_dma_len(sgent); + + for (j = 0; j < len; j += max_size) { ++ u32 waits; + struct bcm2835_dma_cb *control_block = + &d->control_block_base[i+splitct]; + +@@ -879,7 +880,7 @@ static struct dma_async_tx_descriptor *b + } + + /* Common part */ +- u32 waits = SDHCI_BCM_DMA_WAITS; ++ waits = SDHCI_BCM_DMA_WAITS; + if ((dma_debug >> 0) & 0x1f) + waits = (dma_debug >> 0) & 0x1f; + control_block->info |= BCM2835_DMA_WAITS(waits); +@@ -1074,6 +1075,14 @@ static int bcm2835_dma_probe(struct plat + int rc; + int i; + int irq; ++#ifdef CONFIG_DMA_BCM2708_LEGACY ++ static const u32 wanted_features[] = { ++ BCM_DMA_FEATURE_FAST, ++ BCM_DMA_FEATURE_NORMAL, ++ BCM_DMA_FEATURE_LITE ++ }; ++ int j; ++#endif + + + if (!pdev->dev.dma_mask) +@@ -1120,20 +1129,24 @@ static int bcm2835_dma_probe(struct plat + + platform_set_drvdata(pdev, od); + +- for (i = 0; i < 5; i++) { ++ for (i = 0, j = 0; j < ARRAY_SIZE(wanted_features);) { ++ + void __iomem *chan_base; + int chan_id; + +- chan_id = bcm_dma_chan_alloc(BCM_DMA_FEATURE_LITE, +- &chan_base, +- &irq); +- +- if (chan_id < 0) +- break; ++ chan_id = bcm_dma_chan_alloc(wanted_features[j], ++ &chan_base, ++ &irq); ++ ++ if (chan_id < 0) { ++ j++; ++ continue; ++ } + + rc = bcm2708_dma_chan_init(od, chan_base, chan_id, irq); + if (rc) + goto err_no_dma; ++ i++; + } + + if (pdev->dev.of_node) { +@@ -1146,6 +1159,8 @@ static int bcm2835_dma_probe(struct plat + } + } + ++ dev_info(&pdev->dev, "Initialized %i DMA channels (+ 1 legacy)\n", i); ++ + #else + rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)); + if (rc) |