sata_dwc_460ex: device tree may specify dma_channel

Only channel 0 is currently support and the driver code is fixed on
channel 0. This patch lets device node specifying dma-channel in case
it is not 0. If no dma-channel property is specified, channel 0 is
used as default.

Signed-off-by: Thang Q. Nguyen <tqnguyen@apm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 31 insertions, 17 deletions

diff --git a/drivers/ata/sata_dwc_460ex.c b/drivers/ata/sata_dwc_460ex.c
index ae13ef1945ba..937aeb34b310 100644..100755
--- a/drivers/ata/sata_dwc_460ex.c
+++ b/drivers/ata/sata_dwc_460ex.c
@@ -158,6 +158,7 @@ enum {
 /* Assign HW handshaking interface (x) to destination / source peripheral */
 #define DMA_CFG_HW_HS_DEST(int_num) (((int_num) & 0xF) << 11)
 #define DMA_CFG_HW_HS_SRC(int_num) (((int_num) & 0xF) << 7)
+#define DMA_CFG_HW_CH_PRIOR(int_num) (((int_num) & 0xF) << 5)
 #define DMA_LLP_LMS(addr, master) (((addr) & 0xfffffffc) | (master))
 
 /*
@@ -318,6 +319,7 @@ struct sata_dwc_host_priv {
         u32     dma_interrupt_count;
         struct  ahb_dma_regs    *sata_dma_regs;
         struct  device  *dwc_dev;
+        int     dma_channel;
 };
 struct sata_dwc_host_priv host_pvt;
 /*
@@ -437,15 +439,12 @@ static  void clear_chan_interrupts(int c)
  */
 static int dma_request_channel(void)
 {
-        int i;
-
-        for (i = 0; i < DMA_NUM_CHANS; i++) {
-                if (!(in_le32(&(host_pvt.sata_dma_regs->dma_chan_en.low)) &\
-                        DMA_CHANNEL(i)))
-                        return i;
-        }
-        dev_err(host_pvt.dwc_dev, "%s NO channel chan_en: 0x%08x\n", __func__,
-                in_le32(&(host_pvt.sata_dma_regs->dma_chan_en.low)));
+        /* Check if the channel is not currently in use */
+        if (!(in_le32(&(host_pvt.sata_dma_regs->dma_chan_en.low)) &
+                DMA_CHANNEL(host_pvt.dma_channel)))
+                return host_pvt.dma_channel;
+        dev_err(host_pvt.dwc_dev, "%s Channel %d is currently in use\n",
+                __func__, host_pvt.dma_channel);
         return -1;
 }
 
@@ -481,7 +480,8 @@ static irqreturn_t dma_dwc_interrupt(int irq, void *hsdev_instance)
         dev_dbg(ap->dev, "eot=0x%08x err=0x%08x pending=%d active port=%d\n",
                 tfr_reg, err_reg, hsdevp->dma_pending[tag], port);
 
-        for (chan = 0; chan < DMA_NUM_CHANS; chan++) {
+        chan = host_pvt.dma_channel;
+        if (chan >= 0) {
                 /* Check for end-of-transfer interrupt. */
                 if (tfr_reg & DMA_CHANNEL(chan)) {
                         /*
@@ -534,9 +534,9 @@ static irqreturn_t dma_dwc_interrupt(int irq, void *hsdev_instance)
 static int dma_request_interrupts(struct sata_dwc_device *hsdev, int irq)
 {
         int retval = 0;
-        int chan;
+        int chan = host_pvt.dma_channel;
 
-        for (chan = 0; chan < DMA_NUM_CHANS; chan++) {
+        if (chan >= 0) {
                 /* Unmask error interrupt */
                 out_le32(&(host_pvt.sata_dma_regs)->interrupt_mask.error.low,
                          DMA_ENABLE_CHAN(chan));
@@ -575,7 +575,10 @@ static int map_sg_to_lli(struct scatterlist *sg, int num_elems,
         int fis_len = 0;
         dma_addr_t next_llp;
         int bl;
+        int sms_val, dms_val;
 
+        sms_val = 0;
+        dms_val = 1 + host_pvt.dma_channel;
         dev_dbg(host_pvt.dwc_dev, "%s: sg=%p nelem=%d lli=%p dma_lli=0x%08x"
                 " dmadr=0x%08x\n", __func__, sg, num_elems, lli, (u32)dma_lli,
                 (u32)dmadr_addr);
@@ -635,8 +638,8 @@ static int map_sg_to_lli(struct scatterlist *sg, int num_elems,
 
                                 lli[idx].ctl.low = cpu_to_le32(
                                         DMA_CTL_TTFC(DMA_CTL_TTFC_P2M_DMAC) |
-                                        DMA_CTL_SMS(0) |
-                                        DMA_CTL_DMS(1) |
+                                        DMA_CTL_SMS(sms_val) |
+                                        DMA_CTL_DMS(dms_val) |
                                         DMA_CTL_SRC_MSIZE(bl) |
                                         DMA_CTL_DST_MSIZE(bl) |
                                         DMA_CTL_SINC_NOCHANGE |
@@ -651,8 +654,8 @@ static int map_sg_to_lli(struct scatterlist *sg, int num_elems,
 
                                 lli[idx].ctl.low = cpu_to_le32(
                                         DMA_CTL_TTFC(DMA_CTL_TTFC_M2P_PER) |
-                                        DMA_CTL_SMS(1) |
-                                        DMA_CTL_DMS(0) |
+                                        DMA_CTL_SMS(dms_val) |
+                                        DMA_CTL_DMS(sms_val) |
                                         DMA_CTL_SRC_MSIZE(bl) |
                                         DMA_CTL_DST_MSIZE(bl) |
                                         DMA_CTL_DINC_NOCHANGE |
@@ -744,8 +747,10 @@ static int dma_dwc_xfer_setup(struct scatterlist *sg, int num_elems,
 
         /* Program the CFG register. */
         out_le32(&(host_pvt.sata_dma_regs->chan_regs[dma_ch].cfg.high),
+                 DMA_CFG_HW_HS_SRC(dma_ch) | DMA_CFG_HW_HS_DEST(dma_ch) |
                  DMA_CFG_PROTCTL | DMA_CFG_FCMOD_REQ);
-        out_le32(&(host_pvt.sata_dma_regs->chan_regs[dma_ch].cfg.low), 0);
+        out_le32(&(host_pvt.sata_dma_regs->chan_regs[dma_ch].cfg.low),
+                 DMA_CFG_HW_CH_PRIOR(dma_ch));
 
         /* Program the address of the linked list */
         out_le32(&(host_pvt.sata_dma_regs->chan_regs[dma_ch].llp.low),
@@ -1660,6 +1665,8 @@ static int sata_dwc_probe(struct platform_device *ofdev)
         struct ata_host *host;
         struct ata_port_info pi = sata_dwc_port_info[0];
         const struct ata_port_info *ppi[] = { &pi, NULL };
+        struct device_node *np = ofdev->dev.of_node;
+        u32 dma_chan;
 
         /* Allocate DWC SATA device */
         hsdev = kzalloc(sizeof(*hsdev), GFP_KERNEL);
@@ -1669,6 +1676,13 @@ static int sata_dwc_probe(struct platform_device *ofdev)
                 goto error;
         }
 
+        if (of_property_read_u32(np, "dma-channel", &dma_chan)) {
+                dev_warn(&ofdev->dev, "no dma-channel property set."
+                         " Use channel 0\n");
+                dma_chan = 0;
+        }
+        host_pvt.dma_channel = dma_chan;
+
         /* Ioremap SATA registers */
         base = of_iomap(ofdev->dev.of_node, 0);
         if (!base) {