libata: implement ata_timing_cycle2mode() and use it in libata-acpi and pata_acpi
libata-acpi is using separate timing tables for transfer modes
although libata-core has the complete ata_timing table. Implement
ata_timing_cycle2mode() to look for matching mode given transfer type
and cycle duration and use it in libata-acpi and pata_acpi to replace
private timing tables.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 62c4b32..f01c173 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2903,6 +2903,57 @@
}
/**
+ * ata_timing_cycle2mode - find xfer mode for the specified cycle duration
+ * @xfer_shift: ATA_SHIFT_* value for transfer type to examine.
+ * @cycle: cycle duration in ns
+ *
+ * Return matching xfer mode for @cycle. The returned mode is of
+ * the transfer type specified by @xfer_shift. If @cycle is too
+ * slow for @xfer_shift, 0xff is returned. If @cycle is faster
+ * than the fastest known mode, the fasted mode is returned.
+ *
+ * LOCKING:
+ * None.
+ *
+ * RETURNS:
+ * Matching xfer_mode, 0xff if no match found.
+ */
+u8 ata_timing_cycle2mode(unsigned int xfer_shift, int cycle)
+{
+ u8 base_mode = 0xff, last_mode = 0xff;
+ const struct ata_xfer_ent *ent;
+ const struct ata_timing *t;
+
+ for (ent = ata_xfer_tbl; ent->shift >= 0; ent++)
+ if (ent->shift == xfer_shift)
+ base_mode = ent->base;
+
+ for (t = ata_timing_find_mode(base_mode);
+ t && ata_xfer_mode2shift(t->mode) == xfer_shift; t++) {
+ unsigned short this_cycle;
+
+ switch (xfer_shift) {
+ case ATA_SHIFT_PIO:
+ case ATA_SHIFT_MWDMA:
+ this_cycle = t->cycle;
+ break;
+ case ATA_SHIFT_UDMA:
+ this_cycle = t->udma;
+ break;
+ default:
+ return 0xff;
+ }
+
+ if (cycle > this_cycle)
+ break;
+
+ last_mode = t->mode;
+ }
+
+ return last_mode;
+}
+
+/**
* ata_down_xfermask_limit - adjust dev xfer masks downward
* @dev: Device to adjust xfer masks
* @sel: ATA_DNXFER_* selector
@@ -7630,6 +7681,7 @@
EXPORT_SYMBOL_GPL(ata_timing_find_mode);
EXPORT_SYMBOL_GPL(ata_timing_compute);
EXPORT_SYMBOL_GPL(ata_timing_merge);
+EXPORT_SYMBOL_GPL(ata_timing_cycle2mode);
#ifdef CONFIG_PCI
EXPORT_SYMBOL_GPL(pci_test_config_bits);