[PATCH] libata: reimplement ata_set_mode() using xfer_mask helpers
Use xfer_mask helpers to determine transfer mode. This rewrite also
makes transfer mode determination done before any actual
configuration. This patch doesn't result in any functional changes.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 8849512..d211f0b 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -65,11 +65,9 @@
struct ata_device *dev);
static void ata_set_mode(struct ata_port *ap);
static void ata_dev_set_xfermode(struct ata_port *ap, struct ata_device *dev);
-static unsigned int ata_get_mode_mask(const struct ata_port *ap, int shift);
+static unsigned int ata_dev_xfermask(struct ata_port *ap,
+ struct ata_device *dev);
static int fgb(u32 bitmap);
-static int ata_choose_xfer_mode(const struct ata_port *ap,
- u8 *xfer_mode_out,
- unsigned int *xfer_shift_out);
static unsigned int ata_unique_id = 1;
static struct workqueue_struct *ata_wq;
@@ -1776,51 +1774,42 @@
static int ata_host_set_pio(struct ata_port *ap)
{
- unsigned int mask;
- int x, i;
- u8 base, xfer_mode;
-
- mask = ata_get_mode_mask(ap, ATA_SHIFT_PIO);
- x = fgb(mask);
- if (x < 0) {
- printk(KERN_WARNING "ata%u: no PIO support\n", ap->id);
- return -1;
- }
-
- base = base_from_shift(ATA_SHIFT_PIO);
- xfer_mode = base + x;
-
- DPRINTK("base 0x%x xfer_mode 0x%x mask 0x%x x %d\n",
- (int)base, (int)xfer_mode, mask, x);
+ int i;
for (i = 0; i < ATA_MAX_DEVICES; i++) {
struct ata_device *dev = &ap->device[i];
- if (ata_dev_present(dev)) {
- dev->pio_mode = xfer_mode;
- dev->xfer_mode = xfer_mode;
- dev->xfer_shift = ATA_SHIFT_PIO;
- if (ap->ops->set_piomode)
- ap->ops->set_piomode(ap, dev);
+
+ if (!ata_dev_present(dev))
+ continue;
+
+ if (!dev->pio_mode) {
+ printk(KERN_WARNING "ata%u: no PIO support\n", ap->id);
+ return -1;
}
+
+ dev->xfer_mode = dev->pio_mode;
+ dev->xfer_shift = ATA_SHIFT_PIO;
+ if (ap->ops->set_piomode)
+ ap->ops->set_piomode(ap, dev);
}
return 0;
}
-static void ata_host_set_dma(struct ata_port *ap, u8 xfer_mode,
- unsigned int xfer_shift)
+static void ata_host_set_dma(struct ata_port *ap)
{
int i;
for (i = 0; i < ATA_MAX_DEVICES; i++) {
struct ata_device *dev = &ap->device[i];
- if (ata_dev_present(dev)) {
- dev->dma_mode = xfer_mode;
- dev->xfer_mode = xfer_mode;
- dev->xfer_shift = xfer_shift;
- if (ap->ops->set_dmamode)
- ap->ops->set_dmamode(ap, dev);
- }
+
+ if (!ata_dev_present(dev) || !dev->dma_mode)
+ continue;
+
+ dev->xfer_mode = dev->dma_mode;
+ dev->xfer_shift = ata_xfer_mode2shift(dev->dma_mode);
+ if (ap->ops->set_dmamode)
+ ap->ops->set_dmamode(ap, dev);
}
}
@@ -1835,28 +1824,34 @@
*/
static void ata_set_mode(struct ata_port *ap)
{
- unsigned int xfer_shift;
- u8 xfer_mode;
- int rc;
+ int i, rc;
- /* step 1: always set host PIO timings */
+ /* step 1: calculate xfer_mask */
+ for (i = 0; i < ATA_MAX_DEVICES; i++) {
+ struct ata_device *dev = &ap->device[i];
+ unsigned int xfer_mask;
+
+ if (!ata_dev_present(dev))
+ continue;
+
+ xfer_mask = ata_dev_xfermask(ap, dev);
+
+ dev->pio_mode = ata_xfer_mask2mode(xfer_mask & ATA_MASK_PIO);
+ dev->dma_mode = ata_xfer_mask2mode(xfer_mask & (ATA_MASK_MWDMA |
+ ATA_MASK_UDMA));
+ }
+
+ /* step 2: always set host PIO timings */
rc = ata_host_set_pio(ap);
if (rc)
goto err_out;
- /* step 2: choose the best data xfer mode */
- xfer_mode = xfer_shift = 0;
- rc = ata_choose_xfer_mode(ap, &xfer_mode, &xfer_shift);
- if (rc)
- goto err_out;
-
- /* step 3: if that xfer mode isn't PIO, set host DMA timings */
- if (xfer_shift != ATA_SHIFT_PIO)
- ata_host_set_dma(ap, xfer_mode, xfer_shift);
+ /* step 3: set host DMA timings */
+ ata_host_set_dma(ap);
/* step 4: update devices' xfer mode */
- ata_dev_set_mode(ap, &ap->device[0]);
- ata_dev_set_mode(ap, &ap->device[1]);
+ for (i = 0; i < ATA_MAX_DEVICES; i++)
+ ata_dev_set_mode(ap, &ap->device[i]);
if (ap->flags & ATA_FLAG_PORT_DISABLED)
return;
@@ -2654,77 +2649,45 @@
return 0;
}
-static unsigned int ata_get_mode_mask(const struct ata_port *ap, int shift)
+/**
+ * ata_dev_xfermask - Compute supported xfermask of the given device
+ * @ap: Port on which the device to compute xfermask for resides
+ * @dev: Device to compute xfermask for
+ *
+ * Compute supported xfermask of @dev. This function is
+ * responsible for applying all known limits including host
+ * controller limits, device blacklist, etc...
+ *
+ * LOCKING:
+ * None.
+ *
+ * RETURNS:
+ * Computed xfermask.
+ */
+static unsigned int ata_dev_xfermask(struct ata_port *ap,
+ struct ata_device *dev)
{
- const struct ata_device *master, *slave;
- unsigned int mask;
+ unsigned long xfer_mask;
+ int i;
- master = &ap->device[0];
- slave = &ap->device[1];
+ xfer_mask = ata_pack_xfermask(ap->pio_mask, ap->mwdma_mask,
+ ap->udma_mask);
- WARN_ON(!ata_dev_present(master) && !ata_dev_present(slave));
-
- if (shift == ATA_SHIFT_UDMA) {
- mask = ap->udma_mask;
- if (ata_dev_present(master)) {
- mask &= (master->id[ATA_ID_UDMA_MODES] & 0xff);
- if (ata_dma_blacklisted(master)) {
- mask = 0;
- ata_pr_blacklisted(ap, master);
- }
- }
- if (ata_dev_present(slave)) {
- mask &= (slave->id[ATA_ID_UDMA_MODES] & 0xff);
- if (ata_dma_blacklisted(slave)) {
- mask = 0;
- ata_pr_blacklisted(ap, slave);
- }
- }
- }
- else if (shift == ATA_SHIFT_MWDMA) {
- mask = ap->mwdma_mask;
- if (ata_dev_present(master)) {
- mask &= (master->id[ATA_ID_MWDMA_MODES] & 0x07);
- if (ata_dma_blacklisted(master)) {
- mask = 0;
- ata_pr_blacklisted(ap, master);
- }
- }
- if (ata_dev_present(slave)) {
- mask &= (slave->id[ATA_ID_MWDMA_MODES] & 0x07);
- if (ata_dma_blacklisted(slave)) {
- mask = 0;
- ata_pr_blacklisted(ap, slave);
- }
- }
- }
- else if (shift == ATA_SHIFT_PIO) {
- mask = ap->pio_mask;
- if (ata_dev_present(master)) {
- /* spec doesn't return explicit support for
- * PIO0-2, so we fake it
- */
- u16 tmp_mode = master->id[ATA_ID_PIO_MODES] & 0x03;
- tmp_mode <<= 3;
- tmp_mode |= 0x7;
- mask &= tmp_mode;
- }
- if (ata_dev_present(slave)) {
- /* spec doesn't return explicit support for
- * PIO0-2, so we fake it
- */
- u16 tmp_mode = slave->id[ATA_ID_PIO_MODES] & 0x03;
- tmp_mode <<= 3;
- tmp_mode |= 0x7;
- mask &= tmp_mode;
- }
- }
- else {
- mask = 0xffffffff; /* shut up compiler warning */
- BUG();
+ /* use port-wide xfermask for now */
+ for (i = 0; i < ATA_MAX_DEVICES; i++) {
+ struct ata_device *d = &ap->device[i];
+ if (!ata_dev_present(d))
+ continue;
+ xfer_mask &= ata_id_xfermask(d->id);
+ if (ata_dma_blacklisted(d))
+ xfer_mask &= ~(ATA_MASK_MWDMA | ATA_MASK_UDMA);
}
- return mask;
+ if (ata_dma_blacklisted(dev))
+ printk(KERN_WARNING "ata%u: dev %u is on DMA blacklist, "
+ "disabling DMA\n", ap->id, dev->devno);
+
+ return xfer_mask;
}
/* find greatest bit */
@@ -2741,44 +2704,6 @@
}
/**
- * ata_choose_xfer_mode - attempt to find best transfer mode
- * @ap: Port for which an xfer mode will be selected
- * @xfer_mode_out: (output) SET FEATURES - XFER MODE code
- * @xfer_shift_out: (output) bit shift that selects this mode
- *
- * Based on host and device capabilities, determine the
- * maximum transfer mode that is amenable to all.
- *
- * LOCKING:
- * PCI/etc. bus probe sem.
- *
- * RETURNS:
- * Zero on success, negative on error.
- */
-
-static int ata_choose_xfer_mode(const struct ata_port *ap,
- u8 *xfer_mode_out,
- unsigned int *xfer_shift_out)
-{
- unsigned int mask, shift;
- int x, i;
-
- for (i = 0; i < ARRAY_SIZE(xfer_mode_classes); i++) {
- shift = xfer_mode_classes[i].shift;
- mask = ata_get_mode_mask(ap, shift);
-
- x = fgb(mask);
- if (x >= 0) {
- *xfer_mode_out = xfer_mode_classes[i].base + x;
- *xfer_shift_out = shift;
- return 0;
- }
- }
-
- return -1;
-}
-
-/**
* ata_dev_set_xfermode - Issue SET FEATURES - XFER MODE command
* @ap: Port associated with device @dev
* @dev: Device to which command will be sent