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[PATCH] libata: reimplement ata_set_mode() using xfer_mask helpers
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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>
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Tejun Heo authored and Jeff Garzik committed Mar 12, 2006
1 parent 23e71c3 commit a6d5a51
Showing 1 changed file with 79 additions and 154 deletions.
233 changes: 79 additions & 154 deletions drivers/scsi/libata-core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -65,11 +65,9 @@ static unsigned int ata_dev_init_params(struct ata_port *ap,
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;
Expand Down Expand Up @@ -1776,51 +1774,42 @@ static void ata_dev_set_mode(struct ata_port *ap, struct ata_device *dev)

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);
}
}

Expand All @@ -1835,28 +1824,34 @@ static void ata_host_set_dma(struct ata_port *ap, u8 xfer_mode,
*/
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 */
rc = ata_host_set_pio(ap);
if (rc)
goto err_out;
/* 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;

/* step 2: choose the best data xfer mode */
xfer_mode = xfer_shift = 0;
rc = ata_choose_xfer_mode(ap, &xfer_mode, &xfer_shift);
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 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;
Expand Down Expand Up @@ -2654,77 +2649,45 @@ static int ata_dma_blacklisted(const struct ata_device *dev)
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;

master = &ap->device[0];
slave = &ap->device[1];
unsigned long xfer_mask;
int i;

WARN_ON(!ata_dev_present(master) && !ata_dev_present(slave));
xfer_mask = ata_pack_xfermask(ap->pio_mask, ap->mwdma_mask,
ap->udma_mask);

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 */
Expand All @@ -2740,44 +2703,6 @@ static int fgb(u32 bitmap)
return x;
}

/**
* 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
Expand Down

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