Replace the hardcoded values used to set max_segs/max_seg_size with
a dma_get_channel_caps() query to the dmaengine driver.

Signed-off-by: Matt Porter <mpor...@ti.com>
---
 drivers/mmc/host/davinci_mmc.c            |   66 +++++++++--------------------
 include/linux/platform_data/mmc-davinci.h |    3 --
 2 files changed, 21 insertions(+), 48 deletions(-)

diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c
index 2063677..17e186d 100644
--- a/drivers/mmc/host/davinci_mmc.c
+++ b/drivers/mmc/host/davinci_mmc.c
@@ -144,18 +144,6 @@
 /* MMCSD Init clock in Hz in opendrain mode */
 #define MMCSD_INIT_CLOCK               200000
 
-/*
- * One scatterlist dma "segment" is at most MAX_CCNT rw_threshold units,
- * and we handle up to MAX_NR_SG segments.  MMC_BLOCK_BOUNCE kicks in only
- * for drivers with max_segs == 1, making the segments bigger (64KB)
- * 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 MAX_NR_SG      16
-
 static unsigned rw_threshold = 32;
 module_param(rw_threshold, uint, S_IRUGO);
 MODULE_PARM_DESC(rw_threshold,
@@ -216,8 +204,6 @@ 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
@@ -421,16 +407,7 @@ static int mmc_davinci_send_dma_request(struct 
mmc_davinci_host *host,
        int ret = 0;
 
        if (host->data_dir == DAVINCI_MMC_DATADIR_WRITE) {
-               struct dma_slave_config dma_tx_conf = {
-                       .direction = DMA_MEM_TO_DEV,
-                       .dst_addr = host->mem_res->start + DAVINCI_MMCDXR,
-                       .dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
-                       .dst_maxburst =
-                               rw_threshold / DMA_SLAVE_BUSWIDTH_4_BYTES,
-               };
                chan = host->dma_tx;
-               dmaengine_slave_config(host->dma_tx, &dma_tx_conf);
-
                desc = dmaengine_prep_slave_sg(host->dma_tx,
                                data->sg,
                                host->sg_len,
@@ -443,16 +420,7 @@ static int mmc_davinci_send_dma_request(struct 
mmc_davinci_host *host,
                        goto out;
                }
        } else {
-               struct dma_slave_config dma_rx_conf = {
-                       .direction = DMA_DEV_TO_MEM,
-                       .src_addr = host->mem_res->start + DAVINCI_MMCDRR,
-                       .src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
-                       .src_maxburst =
-                               rw_threshold / DMA_SLAVE_BUSWIDTH_4_BYTES,
-               };
                chan = host->dma_rx;
-               dmaengine_slave_config(host->dma_rx, &dma_rx_conf);
-
                desc = dmaengine_prep_slave_sg(host->dma_rx,
                                data->sg,
                                host->sg_len,
@@ -1165,6 +1133,7 @@ static int __init davinci_mmcsd_probe(struct 
platform_device *pdev)
        struct resource *r, *mem = NULL;
        int ret = 0, irq = 0;
        size_t mem_size;
+       struct dmaengine_chan_caps *dma_chan_caps;
 
        /* REVISIT:  when we're fully converted, fail if pdata is NULL */
 
@@ -1214,12 +1183,6 @@ 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->mmc_irq = irq;
        host->sdio_irq = platform_get_irq(pdev, 1);
@@ -1248,14 +1211,27 @@ static int __init davinci_mmcsd_probe(struct 
platform_device *pdev)
                mmc->caps |= pdata->caps;
        mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
 
-       /* With no iommu coalescing pages, each phys_seg is a hw_seg.
-        * Each hw_seg uses one EDMA parameter RAM slot, always one
-        * channel and then usually some linked slots.
-        */
-       mmc->max_segs           = MAX_NR_SG;
+       {
+               struct dma_slave_config dma_txrx_conf = {
+                       .src_addr = host->mem_res->start + DAVINCI_MMCDRR,
+                       .src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
+                       .src_maxburst =
+                               rw_threshold / DMA_SLAVE_BUSWIDTH_4_BYTES,
+                       .dst_addr = host->mem_res->start + DAVINCI_MMCDXR,
+                       .dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES,
+                       .dst_maxburst =
+                               rw_threshold / DMA_SLAVE_BUSWIDTH_4_BYTES,
+               };
+               dmaengine_slave_config(host->dma_tx, &dma_txrx_conf);
+               dmaengine_slave_config(host->dma_rx, &dma_txrx_conf);
+       }
 
-       /* EDMA limit per hw segment (one or two MBytes) */
-       mmc->max_seg_size       = MAX_CCNT * rw_threshold;
+       /* Just check one channel for the DMA SG limits */
+       dma_chan_caps = dma_get_channel_caps(host->dma_tx, DMA_MEM_TO_DEV);
+       if (dma_chan_caps) {
+               mmc->max_segs = dma_chan_caps->seg_nr;
+               mmc->max_seg_size = dma_chan_caps->seg_len;
+       }
 
        /* MMC/SD controller limits for multiblock requests */
        mmc->max_blk_size       = 4095;  /* BLEN is 12 bits */
diff --git a/include/linux/platform_data/mmc-davinci.h 
b/include/linux/platform_data/mmc-davinci.h
index 5ba6b22..6910209 100644
--- a/include/linux/platform_data/mmc-davinci.h
+++ b/include/linux/platform_data/mmc-davinci.h
@@ -25,9 +25,6 @@ struct davinci_mmc_config {
 
        /* Version of the MMC/SD controller */
        u8      version;
-
-       /* Number of sg segments */
-       u8      nr_sg;
 };
 void davinci_setup_mmc(int module, struct davinci_mmc_config *config);
 
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to