[libata] pata_bf54x: Support sg list in bmdma transfer.

BF54x on-chip ATAPI controller allows maximum 0x1fffe bytes to be transfered
in one ATAPI transfer. So, set the max sg_tablesize to 4.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 88 insertions, 79 deletions

diff --git a/drivers/ata/pata_bf54x.c b/drivers/ata/pata_bf54x.c
index d6a4677fdf71..1e65842e2ca7 100644
--- a/drivers/ata/pata_bf54x.c
+++ b/drivers/ata/pata_bf54x.c
@@ -251,6 +251,8 @@ static const u32 udma_tenvmin = 20;
 static const u32 udma_tackmin = 20;
 static const u32 udma_tssmin = 50;
 
+#define BFIN_MAX_SG_SEGMENTS 4
+
 /**
  *
  *      Function:       num_clocks_min
@@ -829,79 +831,61 @@ static void bfin_set_devctl(struct ata_port *ap, u8 ctl)
 
 static void bfin_bmdma_setup(struct ata_queued_cmd *qc)
 {
-        unsigned short config = WDSIZE_16;
+        struct ata_port *ap = qc->ap;
+        struct dma_desc_array *dma_desc_cpu = (struct dma_desc_array *)ap->bmdma_prd;
+        void __iomem *base = (void __iomem *)ap->ioaddr.ctl_addr;
+        unsigned short config = DMAFLOW_ARRAY | NDSIZE_5 | RESTART | WDSIZE_16 | DMAEN;
         struct scatterlist *sg;
         unsigned int si;
+        unsigned int channel;
+        unsigned int dir;
+        unsigned int size = 0;
 
         dev_dbg(qc->ap->dev, "in atapi dma setup\n");
         /* Program the ATA_CTRL register with dir */
         if (qc->tf.flags & ATA_TFLAG_WRITE) {
-                /* fill the ATAPI DMA controller */
-                set_dma_config(CH_ATAPI_TX, config);
-                set_dma_x_modify(CH_ATAPI_TX, 2);
-                for_each_sg(qc->sg, sg, qc->n_elem, si) {
-                        set_dma_start_addr(CH_ATAPI_TX, sg_dma_address(sg));
-                        set_dma_x_count(CH_ATAPI_TX, sg_dma_len(sg) >> 1);
-                }
+                channel = CH_ATAPI_TX;
+                dir = DMA_TO_DEVICE;
         } else {
+                channel = CH_ATAPI_RX;
+                dir = DMA_FROM_DEVICE;
                 config |= WNR;
-                /* fill the ATAPI DMA controller */
-                set_dma_config(CH_ATAPI_RX, config);
-                set_dma_x_modify(CH_ATAPI_RX, 2);
-                for_each_sg(qc->sg, sg, qc->n_elem, si) {
-                        set_dma_start_addr(CH_ATAPI_RX, sg_dma_address(sg));
-                        set_dma_x_count(CH_ATAPI_RX, sg_dma_len(sg) >> 1);
-                }
         }
-}
 
-/**
- *      bfin_bmdma_start - Start an IDE DMA transaction
- *      @qc: Info associated with this ATA transaction.
- *
- *      Note: Original code is ata_bmdma_start().
- */
+        dma_map_sg(ap->dev, qc->sg, qc->n_elem, dir);
 
-static void bfin_bmdma_start(struct ata_queued_cmd *qc)
-{
-        struct ata_port *ap = qc->ap;
-        void __iomem *base = (void __iomem *)ap->ioaddr.ctl_addr;
-        struct scatterlist *sg;
-        unsigned int si;
+        /* fill the ATAPI DMA controller */
+        for_each_sg(qc->sg, sg, qc->n_elem, si) {
+                dma_desc_cpu[si].start_addr = sg_dma_address(sg);
+                dma_desc_cpu[si].cfg = config;
+                dma_desc_cpu[si].x_count = sg_dma_len(sg) >> 1;
+                dma_desc_cpu[si].x_modify = 2;
+                size += sg_dma_len(sg);
+        }
 
-        dev_dbg(qc->ap->dev, "in atapi dma start\n");
-        if (!(ap->udma_mask || ap->mwdma_mask))
-                return;
+        /* Set the last descriptor to stop mode */
+        dma_desc_cpu[qc->n_elem - 1].cfg &= ~(DMAFLOW | NDSIZE);
 
-        /* start ATAPI DMA controller*/
-        if (qc->tf.flags & ATA_TFLAG_WRITE) {
-                /*
-                 * On blackfin arch, uncacheable memory is not
-                 * allocated with flag GFP_DMA. DMA buffer from
-                 * common kenel code should be flushed if WB
-                 * data cache is enabled. Otherwise, this loop
-                 * is an empty loop and optimized out.
-                 */
-                for_each_sg(qc->sg, sg, qc->n_elem, si) {
-                        flush_dcache_range(sg_dma_address(sg),
-                                sg_dma_address(sg) + sg_dma_len(sg));
-                }
-                enable_dma(CH_ATAPI_TX);
-                dev_dbg(qc->ap->dev, "enable udma write\n");
+        flush_dcache_range((unsigned int)dma_desc_cpu,
+                (unsigned int)dma_desc_cpu +
+                        qc->n_elem * sizeof(struct dma_desc_array));
 
-                /* Send ATA DMA write command */
-                bfin_exec_command(ap, &qc->tf);
+        /* Enable ATA DMA operation*/
+        set_dma_curr_desc_addr(channel, (unsigned long *)ap->bmdma_prd_dma);
+        set_dma_x_count(channel, 0);
+        set_dma_x_modify(channel, 0);
+        set_dma_config(channel, config);
+
+        SSYNC();
+
+        /* Send ATA DMA command */
+        bfin_exec_command(ap, &qc->tf);
 
+        if (qc->tf.flags & ATA_TFLAG_WRITE) {
                 /* set ATA DMA write direction */
                 ATAPI_SET_CONTROL(base, (ATAPI_GET_CONTROL(base)
                         | XFER_DIR));
         } else {
-                enable_dma(CH_ATAPI_RX);
-                dev_dbg(qc->ap->dev, "enable udma read\n");
-
-                /* Send ATA DMA read command */
-                bfin_exec_command(ap, &qc->tf);
-
                 /* set ATA DMA read direction */
                 ATAPI_SET_CONTROL(base, (ATAPI_GET_CONTROL(base)
                         & ~XFER_DIR));
@@ -913,12 +897,28 @@ static void bfin_bmdma_start(struct ata_queued_cmd *qc)
         /* Set ATAPI state machine contorl in terminate sequence */
         ATAPI_SET_CONTROL(base, ATAPI_GET_CONTROL(base) | END_ON_TERM);
 
-        /* Set transfer length to buffer len */
-        for_each_sg(qc->sg, sg, qc->n_elem, si) {
-                ATAPI_SET_XFER_LEN(base, (sg_dma_len(sg) >> 1));
-        }
+        /* Set transfer length to the total size of sg buffers */
+        ATAPI_SET_XFER_LEN(base, size >> 1);
+}
 
-        /* Enable ATA DMA operation*/
+/**
+ *      bfin_bmdma_start - Start an IDE DMA transaction
+ *      @qc: Info associated with this ATA transaction.
+ *
+ *      Note: Original code is ata_bmdma_start().
+ */
+
+static void bfin_bmdma_start(struct ata_queued_cmd *qc)
+{
+        struct ata_port *ap = qc->ap;
+        void __iomem *base = (void __iomem *)ap->ioaddr.ctl_addr;
+
+        dev_dbg(qc->ap->dev, "in atapi dma start\n");
+
+        if (!(ap->udma_mask || ap->mwdma_mask))
+                return;
+
+        /* start ATAPI transfer*/
         if (ap->udma_mask)
                 ATAPI_SET_CONTROL(base, ATAPI_GET_CONTROL(base)
                         | ULTRA_START);
@@ -935,34 +935,23 @@ static void bfin_bmdma_start(struct ata_queued_cmd *qc)
 static void bfin_bmdma_stop(struct ata_queued_cmd *qc)
 {
         struct ata_port *ap = qc->ap;
-        struct scatterlist *sg;
-        unsigned int si;
+        unsigned int dir;
 
         dev_dbg(qc->ap->dev, "in atapi dma stop\n");
+
         if (!(ap->udma_mask || ap->mwdma_mask))
                 return;
 
         /* stop ATAPI DMA controller*/
-        if (qc->tf.flags & ATA_TFLAG_WRITE)
+        if (qc->tf.flags & ATA_TFLAG_WRITE) {
+                dir = DMA_TO_DEVICE;
                 disable_dma(CH_ATAPI_TX);
-        else {
+        } else {
+                dir = DMA_FROM_DEVICE;
                 disable_dma(CH_ATAPI_RX);
-                if (ap->hsm_task_state & HSM_ST_LAST) {
-                        /*
-                         * On blackfin arch, uncacheable memory is not
-                         * allocated with flag GFP_DMA. DMA buffer from
-                         * common kenel code should be invalidated if
-                         * data cache is enabled. Otherwise, this loop
-                         * is an empty loop and optimized out.
-                         */
-                        for_each_sg(qc->sg, sg, qc->n_elem, si) {
-                                invalidate_dcache_range(
-                                        sg_dma_address(sg),
-                                        sg_dma_address(sg)
-                                        + sg_dma_len(sg));
-                        }
-                }
         }
+
+        dma_unmap_sg(ap->dev, qc->sg, qc->n_elem, dir);
 }
 
 /**
@@ -1260,6 +1249,11 @@ static void bfin_port_stop(struct ata_port *ap)
 {
         dev_dbg(ap->dev, "in atapi port stop\n");
         if (ap->udma_mask != 0 || ap->mwdma_mask != 0) {
+                dma_free_coherent(ap->dev,
+                        BFIN_MAX_SG_SEGMENTS * sizeof(struct dma_desc_array),
+                        ap->bmdma_prd,
+                        ap->bmdma_prd_dma);
+
                 free_dma(CH_ATAPI_RX);
                 free_dma(CH_ATAPI_TX);
         }
@@ -1271,14 +1265,29 @@ static int bfin_port_start(struct ata_port *ap)
         if (!(ap->udma_mask || ap->mwdma_mask))
                 return 0;
 
+        ap->bmdma_prd = dma_alloc_coherent(ap->dev,
+                                BFIN_MAX_SG_SEGMENTS * sizeof(struct dma_desc_array),
+                                &ap->bmdma_prd_dma,
+                                GFP_KERNEL);
+
+        if (ap->bmdma_prd == NULL) {
+                dev_info(ap->dev, "Unable to allocate DMA descriptor array.\n");
+                goto out;
+        }
+
         if (request_dma(CH_ATAPI_RX, "BFIN ATAPI RX DMA") >= 0) {
                 if (request_dma(CH_ATAPI_TX,
                         "BFIN ATAPI TX DMA") >= 0)
                         return 0;
 
                 free_dma(CH_ATAPI_RX);
+                dma_free_coherent(ap->dev,
+                        BFIN_MAX_SG_SEGMENTS * sizeof(struct dma_desc_array),
+                        ap->bmdma_prd,
+                        ap->bmdma_prd_dma);
         }
 
+out:
         ap->udma_mask = 0;
         ap->mwdma_mask = 0;
         dev_err(ap->dev, "Unable to request ATAPI DMA!"
@@ -1400,7 +1409,7 @@ static irqreturn_t bfin_ata_interrupt(int irq, void *dev_instance)
 
 static struct scsi_host_template bfin_sht = {
         ATA_BASE_SHT(DRV_NAME),
-        .sg_tablesize           = SG_NONE,
+        .sg_tablesize           = BFIN_MAX_SG_SEGMENTS,
         .dma_boundary           = ATA_DMA_BOUNDARY,
 };