diff options
Diffstat (limited to 'drivers/mmc')
| -rw-r--r-- | drivers/mmc/host/davinci_mmc.c | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c index 3bd0ba294e9d..547d29c31b40 100644 --- a/drivers/mmc/host/davinci_mmc.c +++ b/drivers/mmc/host/davinci_mmc.c @@ -137,15 +137,15 @@ /* * One scatterlist dma "segment" is at most MAX_CCNT rw_threshold units, - * and we handle up to NR_SG segments. MMC_BLOCK_BOUNCE kicks in only + * and we handle up to MAX_NR_SG segments. MMC_BLOCK_BOUNCE kicks in only * for drivers with max_hw_segs == 1, making the segments bigger (64KB) - * than the page or two that's otherwise typical. NR_SG == 16 gives at - * least the same throughput boost, using EDMA transfer linkage instead - * of spending CPU time copying pages. + * than the page or two that's otherwise typical. nr_sg (passed from + * platform data) == 16 gives at least the same throughput boost, using + * EDMA transfer linkage instead of spending CPU time copying pages. */ #define MAX_CCNT ((1 << 16) - 1) -#define NR_SG 16 +#define MAX_NR_SG 16 static unsigned rw_threshold = 32; module_param(rw_threshold, uint, S_IRUGO); @@ -192,7 +192,7 @@ struct mmc_davinci_host { struct edmacc_param tx_template; struct edmacc_param rx_template; unsigned n_link; - u32 links[NR_SG - 1]; + u32 links[MAX_NR_SG - 1]; /* For PIO we walk scatterlists one segment at a time. */ unsigned int sg_len; @@ -202,6 +202,8 @@ struct mmc_davinci_host { u8 version; /* for ns in one cycle calculation */ unsigned ns_in_one_cycle; + /* Number of sg segments */ + u8 nr_sg; #ifdef CONFIG_CPU_FREQ struct notifier_block freq_transition; #endif @@ -568,6 +570,7 @@ davinci_release_dma_channels(struct mmc_davinci_host *host) static int __init davinci_acquire_dma_channels(struct mmc_davinci_host *host) { + u32 link_size; int r, i; /* Acquire master DMA write channel */ @@ -593,7 +596,8 @@ static int __init davinci_acquire_dma_channels(struct mmc_davinci_host *host) /* Allocate parameter RAM slots, which will later be bound to a * channel as needed to handle a scatterlist. */ - for (i = 0; i < ARRAY_SIZE(host->links); i++) { + link_size = min_t(unsigned, host->nr_sg, ARRAY_SIZE(host->links)); + for (i = 0; i < link_size; i++) { r = edma_alloc_slot(EDMA_CTLR(host->txdma), EDMA_SLOT_ANY); if (r < 0) { dev_dbg(mmc_dev(host->mmc), "dma PaRAM alloc --> %d\n", @@ -1202,6 +1206,12 @@ static int __init davinci_mmcsd_probe(struct platform_device *pdev) init_mmcsd_host(host); + if (pdata->nr_sg) + host->nr_sg = pdata->nr_sg - 1; + + if (host->nr_sg > MAX_NR_SG || !host->nr_sg) + host->nr_sg = MAX_NR_SG; + host->use_dma = use_dma; host->irq = irq; |