[PATCH] libata: implement new SCR handling and port on/offline functions
Implement ata_scr_{valid|read|write|write_flush}() and
ata_port_{online|offline}(). These functions replace
scr_{read|write}() and sata_dev_present().
Major difference between between the new SCR functions and the old
ones is that the new ones have a way to signal error to the caller.
This makes handling SCR-available and SCR-unavailable cases in the
same path easier. Also, it eases later PM implementation where SCR
access can fail due to various reasons.
ata_port_{online|offline}() functions return 1 only when they are
affirmitive of the condition. e.g. if SCR is unaccessible or
presence cannot be determined for other reasons, these functions
return 0. So, ata_port_online() != !ata_port_offline(). This
distinction is useful in many exception handling cases.
Signed-off-by: Tejun Heo <htejun@gmail.com>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index f29d43c..b9c5cbf 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -4365,6 +4365,143 @@
return IRQ_RETVAL(handled);
}
+/**
+ * sata_scr_valid - test whether SCRs are accessible
+ * @ap: ATA port to test SCR accessibility for
+ *
+ * Test whether SCRs are accessible for @ap.
+ *
+ * LOCKING:
+ * None.
+ *
+ * RETURNS:
+ * 1 if SCRs are accessible, 0 otherwise.
+ */
+int sata_scr_valid(struct ata_port *ap)
+{
+ return ap->cbl == ATA_CBL_SATA && ap->ops->scr_read;
+}
+
+/**
+ * sata_scr_read - read SCR register of the specified port
+ * @ap: ATA port to read SCR for
+ * @reg: SCR to read
+ * @val: Place to store read value
+ *
+ * Read SCR register @reg of @ap into *@val. This function is
+ * guaranteed to succeed if the cable type of the port is SATA
+ * and the port implements ->scr_read.
+ *
+ * LOCKING:
+ * None.
+ *
+ * RETURNS:
+ * 0 on success, negative errno on failure.
+ */
+int sata_scr_read(struct ata_port *ap, int reg, u32 *val)
+{
+ if (sata_scr_valid(ap)) {
+ *val = ap->ops->scr_read(ap, reg);
+ return 0;
+ }
+ return -EOPNOTSUPP;
+}
+
+/**
+ * sata_scr_write - write SCR register of the specified port
+ * @ap: ATA port to write SCR for
+ * @reg: SCR to write
+ * @val: value to write
+ *
+ * Write @val to SCR register @reg of @ap. This function is
+ * guaranteed to succeed if the cable type of the port is SATA
+ * and the port implements ->scr_read.
+ *
+ * LOCKING:
+ * None.
+ *
+ * RETURNS:
+ * 0 on success, negative errno on failure.
+ */
+int sata_scr_write(struct ata_port *ap, int reg, u32 val)
+{
+ if (sata_scr_valid(ap)) {
+ ap->ops->scr_write(ap, reg, val);
+ return 0;
+ }
+ return -EOPNOTSUPP;
+}
+
+/**
+ * sata_scr_write_flush - write SCR register of the specified port and flush
+ * @ap: ATA port to write SCR for
+ * @reg: SCR to write
+ * @val: value to write
+ *
+ * This function is identical to sata_scr_write() except that this
+ * function performs flush after writing to the register.
+ *
+ * LOCKING:
+ * None.
+ *
+ * RETURNS:
+ * 0 on success, negative errno on failure.
+ */
+int sata_scr_write_flush(struct ata_port *ap, int reg, u32 val)
+{
+ if (sata_scr_valid(ap)) {
+ ap->ops->scr_write(ap, reg, val);
+ ap->ops->scr_read(ap, reg);
+ return 0;
+ }
+ return -EOPNOTSUPP;
+}
+
+/**
+ * ata_port_online - test whether the given port is online
+ * @ap: ATA port to test
+ *
+ * Test whether @ap is online. Note that this function returns 0
+ * if online status of @ap cannot be obtained, so
+ * ata_port_online(ap) != !ata_port_offline(ap).
+ *
+ * LOCKING:
+ * None.
+ *
+ * RETURNS:
+ * 1 if the port online status is available and online.
+ */
+int ata_port_online(struct ata_port *ap)
+{
+ u32 sstatus;
+
+ if (!sata_scr_read(ap, SCR_STATUS, &sstatus) && (sstatus & 0xf) == 0x3)
+ return 1;
+ return 0;
+}
+
+/**
+ * ata_port_offline - test whether the given port is offline
+ * @ap: ATA port to test
+ *
+ * Test whether @ap is offline. Note that this function returns
+ * 0 if offline status of @ap cannot be obtained, so
+ * ata_port_online(ap) != !ata_port_offline(ap).
+ *
+ * LOCKING:
+ * None.
+ *
+ * RETURNS:
+ * 1 if the port offline status is available and offline.
+ */
+int ata_port_offline(struct ata_port *ap)
+{
+ u32 sstatus;
+
+ if (!sata_scr_read(ap, SCR_STATUS, &sstatus) && (sstatus & 0xf) != 0x3)
+ return 1;
+ return 0;
+}
/*
* Execute a 'simple' command, that only consists of the opcode 'cmd' itself,
@@ -5133,6 +5270,12 @@
EXPORT_SYMBOL_GPL(ata_scsi_slave_config);
EXPORT_SYMBOL_GPL(ata_scsi_release);
EXPORT_SYMBOL_GPL(ata_host_intr);
+EXPORT_SYMBOL_GPL(sata_scr_valid);
+EXPORT_SYMBOL_GPL(sata_scr_read);
+EXPORT_SYMBOL_GPL(sata_scr_write);
+EXPORT_SYMBOL_GPL(sata_scr_write_flush);
+EXPORT_SYMBOL_GPL(ata_port_online);
+EXPORT_SYMBOL_GPL(ata_port_offline);
EXPORT_SYMBOL_GPL(ata_id_string);
EXPORT_SYMBOL_GPL(ata_id_c_string);
EXPORT_SYMBOL_GPL(ata_scsi_simulate);