From ffd9a1ba9fdb7f2bd1d1ad9b9243d34e96756ba2 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 2 May 2019 17:19:18 +0100 Subject: ARM: riscpc: fix DMA DMA got broken a while back in two different ways: 1) a change in the behaviour of disable_irq() to wait for the interrupt to finish executing causes us to deadlock at the end of DMA. 2) a change to avoid modifying the scatterlist left the first transfer uninitialised. DMA is only used with expansion cards, so has gone unnoticed. Fixes: fa4e99899932 ("[ARM] dma: RiscPC: don't modify DMA SG entries") Signed-off-by: Russell King --- arch/arm/mach-rpc/dma.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'arch/arm/mach-rpc/dma.c') diff --git a/arch/arm/mach-rpc/dma.c b/arch/arm/mach-rpc/dma.c index fb48f3141fb4..c4c96661eb89 100644 --- a/arch/arm/mach-rpc/dma.c +++ b/arch/arm/mach-rpc/dma.c @@ -131,7 +131,7 @@ static irqreturn_t iomd_dma_handle(int irq, void *dev_id) } while (1); idma->state = ~DMA_ST_AB; - disable_irq(irq); + disable_irq_nosync(irq); return IRQ_HANDLED; } @@ -174,6 +174,9 @@ static void iomd_enable_dma(unsigned int chan, dma_t *dma) DMA_FROM_DEVICE : DMA_TO_DEVICE); } + idma->dma_addr = idma->dma.sg->dma_address; + idma->dma_len = idma->dma.sg->length; + iomd_writeb(DMA_CR_C, dma_base + CR); idma->state = DMA_ST_AB; } -- cgit v1.2.3-73-gaa49b From 8194468fadaaac5e04558d955e7bff8692212459 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 2 May 2019 17:37:51 +0100 Subject: ARM: riscpc: dma: eliminate "cur_sg" scatterlist usage All we really need is the DMA address and size, we don't need the baggage of a full scatterlist structure. Signed-off-by: Russell King --- arch/arm/mach-rpc/dma.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) (limited to 'arch/arm/mach-rpc/dma.c') diff --git a/arch/arm/mach-rpc/dma.c b/arch/arm/mach-rpc/dma.c index c4c96661eb89..37750c6493b4 100644 --- a/arch/arm/mach-rpc/dma.c +++ b/arch/arm/mach-rpc/dma.c @@ -30,7 +30,8 @@ struct iomd_dma { unsigned int state; unsigned long base; /* Controller base address */ int irq; /* Controller IRQ */ - struct scatterlist cur_sg; /* Current controller buffer */ + dma_addr_t cur_addr; + unsigned int cur_len; dma_addr_t dma_addr; unsigned int dma_len; }; @@ -53,13 +54,13 @@ typedef enum { #define CR (IOMD_IO0CR - IOMD_IO0CURA) #define ST (IOMD_IO0ST - IOMD_IO0CURA) -static void iomd_get_next_sg(struct scatterlist *sg, struct iomd_dma *idma) +static void iomd_get_next_sg(struct iomd_dma *idma) { unsigned long end, offset, flags = 0; if (idma->dma.sg) { - sg->dma_address = idma->dma_addr; - offset = sg->dma_address & ~PAGE_MASK; + idma->cur_addr = idma->dma_addr; + offset = idma->cur_addr & ~PAGE_MASK; end = offset + idma->dma_len; @@ -69,7 +70,7 @@ static void iomd_get_next_sg(struct scatterlist *sg, struct iomd_dma *idma) if (offset + TRANSFER_SIZE >= end) flags |= DMA_END_L; - sg->length = end - TRANSFER_SIZE; + idma->cur_len = end - TRANSFER_SIZE; idma->dma_len -= end - offset; idma->dma_addr += end - offset; @@ -87,11 +88,11 @@ static void iomd_get_next_sg(struct scatterlist *sg, struct iomd_dma *idma) } } else { flags = DMA_END_S | DMA_END_L; - sg->dma_address = 0; - sg->length = 0; + idma->cur_addr = 0; + idma->cur_len = 0; } - sg->length |= flags; + idma->cur_len |= flags; } static irqreturn_t iomd_dma_handle(int irq, void *dev_id) @@ -107,26 +108,26 @@ static irqreturn_t iomd_dma_handle(int irq, void *dev_id) return IRQ_HANDLED; if ((idma->state ^ status) & DMA_ST_AB) - iomd_get_next_sg(&idma->cur_sg, idma); + iomd_get_next_sg(idma); switch (status & (DMA_ST_OFL | DMA_ST_AB)) { case DMA_ST_OFL: /* OIA */ case DMA_ST_AB: /* .IB */ - iomd_writel(idma->cur_sg.dma_address, base + CURA); - iomd_writel(idma->cur_sg.length, base + ENDA); + iomd_writel(idma->cur_addr, base + CURA); + iomd_writel(idma->cur_len, base + ENDA); idma->state = DMA_ST_AB; break; case DMA_ST_OFL | DMA_ST_AB: /* OIB */ case 0: /* .IA */ - iomd_writel(idma->cur_sg.dma_address, base + CURB); - iomd_writel(idma->cur_sg.length, base + ENDB); + iomd_writel(idma->cur_addr, base + CURB); + iomd_writel(idma->cur_len, base + ENDB); idma->state = 0; break; } if (status & DMA_ST_OFL && - idma->cur_sg.length == (DMA_END_S|DMA_END_L)) + idma->cur_len == (DMA_END_S|DMA_END_L)) break; } while (1); -- cgit v1.2.3-73-gaa49b From 39694ed0dbe17de1eff7850e7481bef98047130c Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 2 May 2019 17:43:36 +0100 Subject: ARM: riscpc: dma: make state a local variable Make state a local variable to avoid rewriting it in the DMA loop. Signed-off-by: Russell King --- arch/arm/mach-rpc/dma.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'arch/arm/mach-rpc/dma.c') diff --git a/arch/arm/mach-rpc/dma.c b/arch/arm/mach-rpc/dma.c index 37750c6493b4..e2b9c95d853b 100644 --- a/arch/arm/mach-rpc/dma.c +++ b/arch/arm/mach-rpc/dma.c @@ -99,15 +99,15 @@ static irqreturn_t iomd_dma_handle(int irq, void *dev_id) { struct iomd_dma *idma = dev_id; unsigned long base = idma->base; + unsigned int state = idma->state; + unsigned int status; do { - unsigned int status; - status = iomd_readb(base + ST); if (!(status & DMA_ST_INT)) - return IRQ_HANDLED; + goto out; - if ((idma->state ^ status) & DMA_ST_AB) + if ((state ^ status) & DMA_ST_AB) iomd_get_next_sg(idma); switch (status & (DMA_ST_OFL | DMA_ST_AB)) { @@ -115,14 +115,14 @@ static irqreturn_t iomd_dma_handle(int irq, void *dev_id) case DMA_ST_AB: /* .IB */ iomd_writel(idma->cur_addr, base + CURA); iomd_writel(idma->cur_len, base + ENDA); - idma->state = DMA_ST_AB; + state = DMA_ST_AB; break; case DMA_ST_OFL | DMA_ST_AB: /* OIB */ case 0: /* .IA */ iomd_writel(idma->cur_addr, base + CURB); iomd_writel(idma->cur_len, base + ENDB); - idma->state = 0; + state = 0; break; } @@ -131,9 +131,10 @@ static irqreturn_t iomd_dma_handle(int irq, void *dev_id) break; } while (1); - idma->state = ~DMA_ST_AB; + state = ~DMA_ST_AB; disable_irq_nosync(irq); - +out: + idma->state = state; return IRQ_HANDLED; } -- cgit v1.2.3-73-gaa49b From e659587c64b3d48a9293e34eb854967654ed98f7 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 2 May 2019 17:50:55 +0100 Subject: ARM: riscpc: dma: improve address/length writing Rearrange writing the DMA addresses to generate more efficient code. Signed-off-by: Russell King --- arch/arm/mach-rpc/dma.c | 26 +++++++++++--------------- 1 file changed, 11 insertions(+), 15 deletions(-) (limited to 'arch/arm/mach-rpc/dma.c') diff --git a/arch/arm/mach-rpc/dma.c b/arch/arm/mach-rpc/dma.c index e2b9c95d853b..6140472d148e 100644 --- a/arch/arm/mach-rpc/dma.c +++ b/arch/arm/mach-rpc/dma.c @@ -100,7 +100,7 @@ static irqreturn_t iomd_dma_handle(int irq, void *dev_id) struct iomd_dma *idma = dev_id; unsigned long base = idma->base; unsigned int state = idma->state; - unsigned int status; + unsigned int status, cur, end; do { status = iomd_readb(base + ST); @@ -110,21 +110,17 @@ static irqreturn_t iomd_dma_handle(int irq, void *dev_id) if ((state ^ status) & DMA_ST_AB) iomd_get_next_sg(idma); - switch (status & (DMA_ST_OFL | DMA_ST_AB)) { - case DMA_ST_OFL: /* OIA */ - case DMA_ST_AB: /* .IB */ - iomd_writel(idma->cur_addr, base + CURA); - iomd_writel(idma->cur_len, base + ENDA); - state = DMA_ST_AB; - break; - - case DMA_ST_OFL | DMA_ST_AB: /* OIB */ - case 0: /* .IA */ - iomd_writel(idma->cur_addr, base + CURB); - iomd_writel(idma->cur_len, base + ENDB); - state = 0; - break; + // This efficiently implements state = OFL != AB ? AB : 0 + state = ((status >> 2) ^ status) & DMA_ST_AB; + if (state) { + cur = CURA; + end = ENDA; + } else { + cur = CURB; + end = ENDB; } + iomd_writel(idma->cur_addr, base + cur); + iomd_writel(idma->cur_len, base + end); if (status & DMA_ST_OFL && idma->cur_len == (DMA_END_S|DMA_END_L)) -- cgit v1.2.3-73-gaa49b From 090a37ceda3ecb02061a1415239aa1a64c184833 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 2 May 2019 17:56:49 +0100 Subject: ARM: riscpc: dma: use __iomem pointers for writing DMA Use __iomem pointers for efficiency to write the DMA registers. This avoids the compiler emitting several instructions for each access to calculate the register address. Signed-off-by: Russell King --- arch/arm/mach-rpc/dma.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) (limited to 'arch/arm/mach-rpc/dma.c') diff --git a/arch/arm/mach-rpc/dma.c b/arch/arm/mach-rpc/dma.c index 6140472d148e..eeda808a7320 100644 --- a/arch/arm/mach-rpc/dma.c +++ b/arch/arm/mach-rpc/dma.c @@ -27,9 +27,9 @@ struct iomd_dma { struct dma_struct dma; - unsigned int state; - unsigned long base; /* Controller base address */ + void __iomem *base; /* Controller base address */ int irq; /* Controller IRQ */ + unsigned int state; dma_addr_t cur_addr; unsigned int cur_len; dma_addr_t dma_addr; @@ -98,12 +98,12 @@ static void iomd_get_next_sg(struct iomd_dma *idma) static irqreturn_t iomd_dma_handle(int irq, void *dev_id) { struct iomd_dma *idma = dev_id; - unsigned long base = idma->base; + void __iomem *base = idma->base; unsigned int state = idma->state; unsigned int status, cur, end; do { - status = iomd_readb(base + ST); + status = readb(base + ST); if (!(status & DMA_ST_INT)) goto out; @@ -119,8 +119,8 @@ static irqreturn_t iomd_dma_handle(int irq, void *dev_id) cur = CURB; end = ENDB; } - iomd_writel(idma->cur_addr, base + cur); - iomd_writel(idma->cur_len, base + end); + writel(idma->cur_addr, base + cur); + writel(idma->cur_len, base + end); if (status & DMA_ST_OFL && idma->cur_len == (DMA_END_S|DMA_END_L)) @@ -152,7 +152,7 @@ static void iomd_free_dma(unsigned int chan, dma_t *dma) static void iomd_enable_dma(unsigned int chan, dma_t *dma) { struct iomd_dma *idma = container_of(dma, struct iomd_dma, dma); - unsigned long dma_base = idma->base; + void __iomem *base = idma->base; unsigned int ctrl = TRANSFER_SIZE | DMA_CR_E; if (idma->dma.invalid) { @@ -175,27 +175,27 @@ static void iomd_enable_dma(unsigned int chan, dma_t *dma) idma->dma_addr = idma->dma.sg->dma_address; idma->dma_len = idma->dma.sg->length; - iomd_writeb(DMA_CR_C, dma_base + CR); + writeb(DMA_CR_C, base + CR); idma->state = DMA_ST_AB; } if (idma->dma.dma_mode == DMA_MODE_READ) ctrl |= DMA_CR_D; - iomd_writeb(ctrl, dma_base + CR); + writeb(ctrl, base + CR); enable_irq(idma->irq); } static void iomd_disable_dma(unsigned int chan, dma_t *dma) { struct iomd_dma *idma = container_of(dma, struct iomd_dma, dma); - unsigned long dma_base = idma->base; + void __iomem *base = idma->base; unsigned long flags; local_irq_save(flags); if (idma->state != ~DMA_ST_AB) disable_irq(idma->irq); - iomd_writeb(0, dma_base + CR); + writeb(0, base + CR); local_irq_restore(flags); } @@ -358,17 +358,17 @@ static int __init rpc_dma_init(void) */ iomd_writeb(DMA_EXT_IO3|DMA_EXT_IO2, IOMD_DMAEXT); - iomd_dma[DMA_0].base = IOMD_IO0CURA; + iomd_dma[DMA_0].base = IOMD_BASE + IOMD_IO0CURA; iomd_dma[DMA_0].irq = IRQ_DMA0; - iomd_dma[DMA_1].base = IOMD_IO1CURA; + iomd_dma[DMA_1].base = IOMD_BASE + IOMD_IO1CURA; iomd_dma[DMA_1].irq = IRQ_DMA1; - iomd_dma[DMA_2].base = IOMD_IO2CURA; + iomd_dma[DMA_2].base = IOMD_BASE + IOMD_IO2CURA; iomd_dma[DMA_2].irq = IRQ_DMA2; - iomd_dma[DMA_3].base = IOMD_IO3CURA; + iomd_dma[DMA_3].base = IOMD_BASE + IOMD_IO3CURA; iomd_dma[DMA_3].irq = IRQ_DMA3; - iomd_dma[DMA_S0].base = IOMD_SD0CURA; + iomd_dma[DMA_S0].base = IOMD_BASE + IOMD_SD0CURA; iomd_dma[DMA_S0].irq = IRQ_DMAS0; - iomd_dma[DMA_S1].base = IOMD_SD1CURA; + iomd_dma[DMA_S1].base = IOMD_BASE + IOMD_SD1CURA; iomd_dma[DMA_S1].irq = IRQ_DMAS1; for (i = DMA_0; i <= DMA_S1; i++) { -- cgit v1.2.3-73-gaa49b