diff options
Diffstat (limited to 'arch/arm/plat-omap/dma.c')
| -rw-r--r-- | arch/arm/plat-omap/dma.c | 50 |
1 files changed, 44 insertions, 6 deletions
diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c index ec7eddf9e525..f5c5b8da9a87 100644 --- a/arch/arm/plat-omap/dma.c +++ b/arch/arm/plat-omap/dma.c @@ -30,6 +30,7 @@ #include <linux/irq.h> #include <linux/io.h> #include <linux/slab.h> +#include <linux/delay.h> #include <asm/system.h> #include <mach/hardware.h> @@ -996,11 +997,17 @@ void omap_start_dma(int lch) l = dma_read(CCR(lch)); /* - * Errata: On ES2.0 BUFFERING disable must be set. - * This will always fail on ES1.0 + * Errata: Inter Frame DMA buffering issue (All OMAP2420 and + * OMAP2430ES1.0): DMA will wrongly buffer elements if packing and + * bursting is enabled. This might result in data gets stalled in + * FIFO at the end of the block. + * Workaround: DMA channels must have BUFFERING_DISABLED bit set to + * guarantee no data will stay in the DMA FIFO in case inter frame + * buffering occurs. */ - if (cpu_is_omap24xx()) - l |= OMAP_DMA_CCR_EN; + if (cpu_is_omap2420() || + (cpu_is_omap2430() && (omap_type() == OMAP2430_REV_ES1_0))) + l |= OMAP_DMA_CCR_BUFFERING_DISABLE; l |= OMAP_DMA_CCR_EN; dma_write(l, CCR(lch)); @@ -1018,8 +1025,39 @@ void omap_stop_dma(int lch) dma_write(0, CICR(lch)); l = dma_read(CCR(lch)); - l &= ~OMAP_DMA_CCR_EN; - dma_write(l, CCR(lch)); + /* OMAP3 Errata i541: sDMA FIFO draining does not finish */ + if (cpu_is_omap34xx() && (l & OMAP_DMA_CCR_SEL_SRC_DST_SYNC)) { + int i = 0; + u32 sys_cf; + + /* Configure No-Standby */ + l = dma_read(OCP_SYSCONFIG); + sys_cf = l; + l &= ~DMA_SYSCONFIG_MIDLEMODE_MASK; + l |= DMA_SYSCONFIG_MIDLEMODE(DMA_IDLEMODE_NO_IDLE); + dma_write(l , OCP_SYSCONFIG); + + l = dma_read(CCR(lch)); + l &= ~OMAP_DMA_CCR_EN; + dma_write(l, CCR(lch)); + + /* Wait for sDMA FIFO drain */ + l = dma_read(CCR(lch)); + while (i < 100 && (l & (OMAP_DMA_CCR_RD_ACTIVE | + OMAP_DMA_CCR_WR_ACTIVE))) { + udelay(5); + i++; + l = dma_read(CCR(lch)); + } + if (i >= 100) + printk(KERN_ERR "DMA drain did not complete on " + "lch %d\n", lch); + /* Restore OCP_SYSCONFIG */ + dma_write(sys_cf, OCP_SYSCONFIG); + } else { + l &= ~OMAP_DMA_CCR_EN; + dma_write(l, CCR(lch)); + } if (!omap_dma_in_1510_mode() && dma_chan[lch].next_lch != -1) { int next_lch, cur_lch = lch; |