diff options
Diffstat (limited to 'arch/arm/plat-omap/dma.c')
| -rw-r--r-- | arch/arm/plat-omap/dma.c | 32 |
1 files changed, 28 insertions, 4 deletions
diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c index 002fb4d96bb..987e6101267 100644 --- a/arch/arm/plat-omap/dma.c +++ b/arch/arm/plat-omap/dma.c @@ -36,12 +36,20 @@ #include <linux/slab.h> #include <linux/delay.h> -#include <asm/system.h> #include <mach/hardware.h> #include <plat/dma.h> #include <plat/tc.h> +/* + * MAX_LOGICAL_DMA_CH_COUNT: the maximum number of logical DMA + * channels that an instance of the SDMA IP block can support. Used + * to size arrays. (The actual maximum on a particular SoC may be less + * than this -- for example, OMAP1 SDMA instances only support 17 logical + * DMA channels.) + */ +#define MAX_LOGICAL_DMA_CH_COUNT 32 + #undef DEBUG #ifndef CONFIG_ARCH_OMAP1 @@ -164,6 +172,8 @@ static inline void set_gdma_dev(int req, int dev) } #else #define set_gdma_dev(req, dev) do {} while (0) +#define omap_readl(reg) 0 +#define omap_writel(val, reg) do {} while (0) #endif void omap_set_dma_priority(int lch, int dst_port, int priority) @@ -882,7 +892,7 @@ void omap_start_dma(int lch) if (!omap_dma_in_1510_mode() && dma_chan[lch].next_lch != -1) { int next_lch, cur_lch; - char dma_chan_link_map[dma_lch_count]; + char dma_chan_link_map[MAX_LOGICAL_DMA_CH_COUNT]; dma_chan_link_map[lch] = 1; /* Set the link register of the first channel */ @@ -915,6 +925,13 @@ void omap_start_dma(int lch) l |= OMAP_DMA_CCR_BUFFERING_DISABLE; l |= OMAP_DMA_CCR_EN; + /* + * As dma_write() uses IO accessors which are weakly ordered, there + * is no guarantee that data in coherent DMA memory will be visible + * to the DMA device. Add a memory barrier here to ensure that any + * such data is visible prior to enabling DMA. + */ + mb(); p->dma_write(l, CCR, lch); dma_chan[lch].flags |= OMAP_DMA_ACTIVE; @@ -964,9 +981,16 @@ void omap_stop_dma(int lch) p->dma_write(l, CCR, lch); } + /* + * Ensure that data transferred by DMA is visible to any access + * after DMA has been disabled. This is important for coherent + * DMA regions. + */ + mb(); + if (!omap_dma_in_1510_mode() && dma_chan[lch].next_lch != -1) { int next_lch, cur_lch = lch; - char dma_chan_link_map[dma_lch_count]; + char dma_chan_link_map[MAX_LOGICAL_DMA_CH_COUNT]; memset(dma_chan_link_map, 0, sizeof(dma_chan_link_map)); do { @@ -2125,7 +2149,7 @@ static int __devexit omap_system_dma_remove(struct platform_device *pdev) static struct platform_driver omap_system_dma_driver = { .probe = omap_system_dma_probe, - .remove = omap_system_dma_remove, + .remove = __devexit_p(omap_system_dma_remove), .driver = { .name = "omap_dma_system" }, |