libata: clean up xfermode / PATA timing related stuff

* s/ATA_BITS_(PIO|MWDMA|UDMA)/ATA_NR_\1_MODES/g

* Consistently use 0xff to indicate invalid transfer mode (0x00 is
  valid for PIO_SLOW).

* Make ata_xfer_mode2mask() return proper mode mask instead of just
  the highest bit.

* Sort ata_timing table in increasing xfermode order and update
  ata_timing_find_mode() accordingly.

This patch doesn't introduce any behavior change.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

2 files changed, 52 insertions, 51 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index a2f2ff864b37..a70ed7b3bc55 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -487,9 +487,9 @@ static const struct ata_xfer_ent {
         int shift, bits;
         u8 base;
 } ata_xfer_tbl[] = {
-        { ATA_SHIFT_PIO, ATA_BITS_PIO, XFER_PIO_0 },
-        { ATA_SHIFT_MWDMA, ATA_BITS_MWDMA, XFER_MW_DMA_0 },
-        { ATA_SHIFT_UDMA, ATA_BITS_UDMA, XFER_UDMA_0 },
+        { ATA_SHIFT_PIO, ATA_NR_PIO_MODES, XFER_PIO_0 },
+        { ATA_SHIFT_MWDMA, ATA_NR_MWDMA_MODES, XFER_MW_DMA_0 },
+        { ATA_SHIFT_UDMA, ATA_NR_UDMA_MODES, XFER_UDMA_0 },
         { -1, },
 };
 
@@ -504,7 +504,7 @@ static const struct ata_xfer_ent {
  *      None.
  *
  *      RETURNS:
- *      Matching XFER_* value, 0 if no match found.
+ *      Matching XFER_* value, 0xff if no match found.
  */
 u8 ata_xfer_mask2mode(unsigned int xfer_mask)
 {
@@ -514,7 +514,7 @@ u8 ata_xfer_mask2mode(unsigned int xfer_mask)
         for (ent = ata_xfer_tbl; ent->shift >= 0; ent++)
                 if (highbit >= ent->shift && highbit < ent->shift + ent->bits)
                         return ent->base + highbit - ent->shift;
-        return 0;
+        return 0xff;
 }
 
 /**
@@ -535,7 +535,8 @@ unsigned int ata_xfer_mode2mask(u8 xfer_mode)
 
         for (ent = ata_xfer_tbl; ent->shift >= 0; ent++)
                 if (xfer_mode >= ent->base && xfer_mode < ent->base + ent->bits)
-                        return 1 << (ent->shift + xfer_mode - ent->base);
+                        return ((2 << (ent->shift + xfer_mode - ent->base)) - 1)
+                                & ~((1 << ent->shift) - 1);
         return 0;
 }
 
@@ -1314,7 +1315,7 @@ void ata_id_to_dma_mode(struct ata_device *dev, u8 unknown)
         /* Select the mode in use */
         mode = ata_xfer_mask2mode(mask);
 
-        if (mode != 0) {
+        if (mode != 0xff) {
                 ata_dev_printk(dev, KERN_INFO, "configured for %s\n",
                        ata_mode_string(mask));
         } else {
@@ -2788,38 +2789,33 @@ int sata_set_spd(struct ata_link *link)
  */
 
 static const struct ata_timing ata_timing[] = {
+/*      { XFER_PIO_SLOW, 120, 290, 240, 960, 290, 240, 960,   0 }, */
+        { XFER_PIO_0,     70, 290, 240, 600, 165, 150, 600,   0 },
+        { XFER_PIO_1,     50, 290,  93, 383, 125, 100, 383,   0 },
+        { XFER_PIO_2,     30, 290,  40, 330, 100,  90, 240,   0 },
+        { XFER_PIO_3,     30,  80,  70, 180,  80,  70, 180,   0 },
+        { XFER_PIO_4,     25,  70,  25, 120,  70,  25, 120,   0 },
+        { XFER_PIO_5,     15,  65,  25, 100,  65,  25, 100,   0 },
+        { XFER_PIO_6,     10,  55,  20,  80,  55,  20,  80,   0 },
 
-        { XFER_UDMA_6,     0,   0,   0,   0,   0,   0,   0,  15 },
-        { XFER_UDMA_5,     0,   0,   0,   0,   0,   0,   0,  20 },
-        { XFER_UDMA_4,     0,   0,   0,   0,   0,   0,   0,  30 },
-        { XFER_UDMA_3,     0,   0,   0,   0,   0,   0,   0,  45 },
+        { XFER_SW_DMA_0, 120,   0,   0,   0, 480, 480, 960,   0 },
+        { XFER_SW_DMA_1,  90,   0,   0,   0, 240, 240, 480,   0 },
+        { XFER_SW_DMA_2,  60,   0,   0,   0, 120, 120, 240,   0 },
 
-        { XFER_MW_DMA_4,  25,   0,   0,   0,  55,  20,  80,   0 },
+        { XFER_MW_DMA_0,  60,   0,   0,   0, 215, 215, 480,   0 },
+        { XFER_MW_DMA_1,  45,   0,   0,   0,  80,  50, 150,   0 },
+        { XFER_MW_DMA_2,  25,   0,   0,   0,  70,  25, 120,   0 },
         { XFER_MW_DMA_3,  25,   0,   0,   0,  65,  25, 100,   0 },
-        { XFER_UDMA_2,     0,   0,   0,   0,   0,   0,   0,  60 },
-        { XFER_UDMA_1,     0,   0,   0,   0,   0,   0,   0,  80 },
-        { XFER_UDMA_0,     0,   0,   0,   0,   0,   0,   0, 120 },
+        { XFER_MW_DMA_4,  25,   0,   0,   0,  55,  20,  80,   0 },
 
 /*      { XFER_UDMA_SLOW,  0,   0,   0,   0,   0,   0,   0, 150 }, */
-
-        { XFER_MW_DMA_2,  25,   0,   0,   0,  70,  25, 120,   0 },
-        { XFER_MW_DMA_1,  45,   0,   0,   0,  80,  50, 150,   0 },
-        { XFER_MW_DMA_0,  60,   0,   0,   0, 215, 215, 480,   0 },
-
-        { XFER_SW_DMA_2,  60,   0,   0,   0, 120, 120, 240,   0 },
-        { XFER_SW_DMA_1,  90,   0,   0,   0, 240, 240, 480,   0 },
-        { XFER_SW_DMA_0, 120,   0,   0,   0, 480, 480, 960,   0 },
-
-        { XFER_PIO_6,     10,  55,  20,  80,  55,  20,  80,   0 },
-        { XFER_PIO_5,     15,  65,  25, 100,  65,  25, 100,   0 },
-        { XFER_PIO_4,     25,  70,  25, 120,  70,  25, 120,   0 },
-        { XFER_PIO_3,     30,  80,  70, 180,  80,  70, 180,   0 },
-
-        { XFER_PIO_2,     30, 290,  40, 330, 100,  90, 240,   0 },
-        { XFER_PIO_1,     50, 290,  93, 383, 125, 100, 383,   0 },
-        { XFER_PIO_0,     70, 290, 240, 600, 165, 150, 600,   0 },
-
-/*      { XFER_PIO_SLOW, 120, 290, 240, 960, 290, 240, 960,   0 }, */
+        { XFER_UDMA_0,     0,   0,   0,   0,   0,   0,   0, 120 },
+        { XFER_UDMA_1,     0,   0,   0,   0,   0,   0,   0,  80 },
+        { XFER_UDMA_2,     0,   0,   0,   0,   0,   0,   0,  60 },
+        { XFER_UDMA_3,     0,   0,   0,   0,   0,   0,   0,  45 },
+        { XFER_UDMA_4,     0,   0,   0,   0,   0,   0,   0,  30 },
+        { XFER_UDMA_5,     0,   0,   0,   0,   0,   0,   0,  20 },
+        { XFER_UDMA_6,     0,   0,   0,   0,   0,   0,   0,  15 },
 
         { 0xFF }
 };
@@ -2854,12 +2850,14 @@ void ata_timing_merge(const struct ata_timing *a, const struct ata_timing *b,
 
 const struct ata_timing *ata_timing_find_mode(u8 xfer_mode)
 {
-        const struct ata_timing *t;
+        const struct ata_timing *t = ata_timing;
+
+        while (xfer_mode > t->mode)
+                t++;
 
-        for (t = ata_timing; t->mode != xfer_mode; t++)
-                if (t->mode == 0xFF)
-                        return NULL;
-        return t;
+        if (xfer_mode == t->mode)
+                return t;
+        return NULL;
 }
 
 int ata_timing_compute(struct ata_device *adev, unsigned short speed,
@@ -3122,7 +3120,7 @@ int ata_do_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
                 dev->dma_mode = ata_xfer_mask2mode(dma_mask);
 
                 found = 1;
-                if (dev->dma_mode)
+                if (dev->dma_mode != 0xff)
                         used_dma = 1;
         }
         if (!found)
@@ -3133,7 +3131,7 @@ int ata_do_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
                 if (!ata_dev_enabled(dev))
                         continue;
 
-                if (!dev->pio_mode) {
+                if (dev->pio_mode == 0xff) {
                         ata_dev_printk(dev, KERN_WARNING, "no PIO support\n");
                         rc = -EINVAL;
                         goto out;
@@ -3147,7 +3145,7 @@ int ata_do_set_mode(struct ata_link *link, struct ata_device **r_failed_dev)
 
         /* step 3: set host DMA timings */
         ata_link_for_each_dev(dev, link) {
-                if (!ata_dev_enabled(dev) || !dev->dma_mode)
+                if (!ata_dev_enabled(dev) || dev->dma_mode == 0xff)
                         continue;
 
                 dev->xfer_mode = dev->dma_mode;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 083dd77b120d..e2ed3bac8c5b 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -269,17 +269,20 @@ enum {
         /* encoding various smaller bitmaps into a single
          * unsigned int bitmap
          */
-        ATA_BITS_PIO            = 7,
-        ATA_BITS_MWDMA          = 5,
-        ATA_BITS_UDMA           = 8,
+        ATA_NR_PIO_MODES        = 7,
+        ATA_NR_MWDMA_MODES      = 5,
+        ATA_NR_UDMA_MODES       = 8,
 
         ATA_SHIFT_PIO           = 0,
-        ATA_SHIFT_MWDMA         = ATA_SHIFT_PIO + ATA_BITS_PIO,
-        ATA_SHIFT_UDMA          = ATA_SHIFT_MWDMA + ATA_BITS_MWDMA,
-
-        ATA_MASK_PIO            = ((1 << ATA_BITS_PIO) - 1) << ATA_SHIFT_PIO,
-        ATA_MASK_MWDMA          = ((1 << ATA_BITS_MWDMA) - 1) << ATA_SHIFT_MWDMA,
-        ATA_MASK_UDMA           = ((1 << ATA_BITS_UDMA) - 1) << ATA_SHIFT_UDMA,
+        ATA_SHIFT_MWDMA         = ATA_SHIFT_PIO + ATA_NR_PIO_MODES,
+        ATA_SHIFT_UDMA          = ATA_SHIFT_MWDMA + ATA_NR_MWDMA_MODES,
+
+        ATA_MASK_PIO            = ((1 << ATA_NR_PIO_MODES) - 1)
+                                        << ATA_SHIFT_PIO,
+        ATA_MASK_MWDMA          = ((1 << ATA_NR_MWDMA_MODES) - 1)
+                                        << ATA_SHIFT_MWDMA,
+        ATA_MASK_UDMA           = ((1 << ATA_NR_UDMA_MODES) - 1)
+                                        << ATA_SHIFT_UDMA,
 
         /* size of buffer to pad xfers ending on unaligned boundaries */
         ATA_DMA_PAD_SZ          = 4,