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authorJeff Garzik <jgarzik@pobox.com>2005-05-30 19:49:12 -0400
committerJeff Garzik <jgarzik@pobox.com>2005-05-30 19:49:12 -0400
commit0cba632b737fc2de76934137b8dccf92d9fa4d19 (patch)
treef2de8c9152ca956aaaaad57ddbe9fc373d4b39d7 /drivers/scsi/libata-core.c
parent780a87f71841932db8dbb0f1eb9daf3a973a6bd6 (diff)
libata: doc updates
Diffstat (limited to 'drivers/scsi/libata-core.c')
-rw-r--r--drivers/scsi/libata-core.c150
1 files changed, 117 insertions, 33 deletions
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 4d707d06a5d1..31b2984f379a 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1190,7 +1190,12 @@ err_out:
* ata_bus_probe - Reset and probe ATA bus
* @ap: Bus to probe
*
+ * Master ATA bus probing function. Initiates a hardware-dependent
+ * bus reset, then attempts to identify any devices found on
+ * the bus.
+ *
* LOCKING:
+ * PCI/etc. bus probe sem.
*
* RETURNS:
* Zero on success, non-zero on error.
@@ -1229,10 +1234,14 @@ err_out:
}
/**
- * ata_port_probe -
- * @ap:
+ * ata_port_probe - Mark port as enabled
+ * @ap: Port for which we indicate enablement
*
- * LOCKING:
+ * Modify @ap data structure such that the system
+ * thinks that the entire port is enabled.
+ *
+ * LOCKING: host_set lock, or some other form of
+ * serialization.
*/
void ata_port_probe(struct ata_port *ap)
@@ -1248,7 +1257,8 @@ void ata_port_probe(struct ata_port *ap)
* PHY registers, to wake up the phy (and device), and
* clear any reset condition.
*
- * LOCKING: None. Serialized during ata_bus_probe().
+ * LOCKING:
+ * PCI/etc. bus probe sem.
*
*/
void __sata_phy_reset(struct ata_port *ap)
@@ -1299,7 +1309,8 @@ void __sata_phy_reset(struct ata_port *ap)
* This function resets the SATA bus, and then probes
* the bus for devices.
*
- * LOCKING: None. Serialized during ata_bus_probe().
+ * LOCKING:
+ * PCI/etc. bus probe sem.
*
*/
void sata_phy_reset(struct ata_port *ap)
@@ -1431,7 +1442,8 @@ static void ata_host_set_dma(struct ata_port *ap, u8 xfer_mode,
*
* Set ATA device disk transfer mode (PIO3, UDMA6, etc.).
*
- * LOCKING: None. Serialized during ata_bus_probe().
+ * LOCKING:
+ * PCI/etc. bus probe sem.
*
*/
static void ata_set_mode(struct ata_port *ap)
@@ -1571,10 +1583,14 @@ static void ata_bus_post_reset(struct ata_port *ap, unsigned int devmask)
}
/**
- * ata_bus_edd -
- * @ap:
+ * ata_bus_edd - Issue EXECUTE DEVICE DIAGNOSTIC command.
+ * @ap: Port to reset and probe
+ *
+ * Use the EXECUTE DEVICE DIAGNOSTIC command to reset and
+ * probe the bus. Not often used these days.
*
- * LOCKING: None. Serialized during ata_bus_probe().
+ * LOCKING:
+ * PCI/etc. bus probe sem.
*
*/
@@ -1651,8 +1667,8 @@ static unsigned int ata_bus_softreset(struct ata_port *ap,
* the device is ATA or ATAPI.
*
* LOCKING:
- * Inherited from caller. Some functions called by this function
- * obtain the host_set lock.
+ * PCI/etc. bus probe sem.
+ * Obtains host_set lock.
*
* SIDE EFFECTS:
* Sets ATA_FLAG_PORT_DISABLED if bus reset fails.
@@ -1894,7 +1910,11 @@ static int fgb(u32 bitmap)
* @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.
@@ -1930,7 +1950,8 @@ static int ata_choose_xfer_mode(struct ata_port *ap,
* Issue SET FEATURES - XFER MODE command to device @dev
* on port @ap.
*
- * LOCKING: None. Serialized during ata_bus_probe().
+ * LOCKING:
+ * PCI/etc. bus probe sem.
*/
static void ata_dev_set_xfermode(struct ata_port *ap, struct ata_device *dev)
@@ -1968,10 +1989,13 @@ static void ata_dev_set_xfermode(struct ata_port *ap, struct ata_device *dev)
}
/**
- * ata_sg_clean -
- * @qc:
+ * ata_sg_clean - Unmap DMA memory associated with command
+ * @qc: Command containing DMA memory to be released
+ *
+ * Unmap all mapped DMA memory associated with this command.
*
* LOCKING:
+ * spin_lock_irqsave(host_set lock)
*/
static void ata_sg_clean(struct ata_queued_cmd *qc)
@@ -2058,6 +2082,8 @@ static void ata_fill_sg(struct ata_queued_cmd *qc)
* supplied PACKET command.
*
* LOCKING:
+ * spin_lock_irqsave(host_set lock)
+ *
* RETURNS: 0 when ATAPI DMA can be used
* nonzero otherwise
*/
@@ -2088,6 +2114,19 @@ void ata_qc_prep(struct ata_queued_cmd *qc)
ata_fill_sg(qc);
}
+/**
+ * ata_sg_init_one - Associate command with memory buffer
+ * @qc: Command to be associated
+ * @buf: Memory buffer
+ * @buflen: Length of memory buffer, in bytes.
+ *
+ * Initialize the data-related elements of queued_cmd @qc
+ * to point to a single memory buffer, @buf of byte length @buflen.
+ *
+ * LOCKING:
+ * spin_lock_irqsave(host_set lock)
+ */
+
void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf, unsigned int buflen)
{
struct scatterlist *sg;
@@ -2105,6 +2144,20 @@ void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf, unsigned int buflen)
sg->length = buflen;
}
+/**
+ * ata_sg_init - Associate command with scatter-gather table.
+ * @qc: Command to be associated
+ * @sg: Scatter-gather table.
+ * @n_elem: Number of elements in s/g table.
+ *
+ * Initialize the data-related elements of queued_cmd @qc
+ * to point to a scatter-gather table @sg, containing @n_elem
+ * elements.
+ *
+ * LOCKING:
+ * spin_lock_irqsave(host_set lock)
+ */
+
void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
unsigned int n_elem)
{
@@ -2114,14 +2167,16 @@ void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
}
/**
- * ata_sg_setup_one -
- * @qc:
+ * ata_sg_setup_one - DMA-map the memory buffer associated with a command.
+ * @qc: Command with memory buffer to be mapped.
+ *
+ * DMA-map the memory buffer associated with queued_cmd @qc.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*
* RETURNS:
- *
+ * Zero on success, negative on error.
*/
static int ata_sg_setup_one(struct ata_queued_cmd *qc)
@@ -2146,13 +2201,16 @@ static int ata_sg_setup_one(struct ata_queued_cmd *qc)
}
/**
- * ata_sg_setup -
- * @qc:
+ * ata_sg_setup - DMA-map the scatter-gather table associated with a command.
+ * @qc: Command with scatter-gather table to be mapped.
+ *
+ * DMA-map the scatter-gather table associated with queued_cmd @qc.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*
* RETURNS:
+ * Zero on success, negative on error.
*
*/
@@ -2182,6 +2240,7 @@ static int ata_sg_setup(struct ata_queued_cmd *qc)
* @ap:
*
* LOCKING:
+ * None. (executing in kernel thread context)
*
* RETURNS:
*
@@ -2229,6 +2288,7 @@ static unsigned long ata_pio_poll(struct ata_port *ap)
* @ap:
*
* LOCKING:
+ * None. (executing in kernel thread context)
*/
static void ata_pio_complete (struct ata_port *ap)
@@ -2446,6 +2506,7 @@ err_out:
* @ap:
*
* LOCKING:
+ * None. (executing in kernel thread context)
*/
static void ata_pio_block(struct ata_port *ap)
@@ -2614,6 +2675,7 @@ static void atapi_request_sense(struct ata_port *ap, struct ata_device *dev,
* transaction completed successfully.
*
* LOCKING:
+ * Inherited from SCSI layer (none, can sleep)
*/
static void ata_qc_timeout(struct ata_queued_cmd *qc)
@@ -2723,6 +2785,7 @@ out:
* @dev: Device from whom we request an available command structure
*
* LOCKING:
+ * None.
*/
static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
@@ -2748,6 +2811,7 @@ static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
* @dev: Device from whom we request an available command structure
*
* LOCKING:
+ * None.
*/
struct ata_queued_cmd *ata_qc_new_init(struct ata_port *ap,
@@ -2812,6 +2876,7 @@ static void __ata_qc_complete(struct ata_queued_cmd *qc)
* in case something prevents using it.
*
* LOCKING:
+ * spin_lock_irqsave(host_set lock)
*
*/
void ata_qc_free(struct ata_queued_cmd *qc)
@@ -2825,9 +2890,13 @@ void ata_qc_free(struct ata_queued_cmd *qc)
/**
* ata_qc_complete - Complete an active ATA command
* @qc: Command to complete
- * @drv_stat: ATA status register contents
+ * @drv_stat: ATA Status register contents
+ *
+ * Indicate to the mid and upper layers that an ATA
+ * command has completed, with either an ok or not-ok status.
*
* LOCKING:
+ * spin_lock_irqsave(host_set lock)
*
*/
@@ -3234,13 +3303,18 @@ idle_irq:
/**
* ata_interrupt - Default ATA host interrupt handler
- * @irq: irq line
- * @dev_instance: pointer to our host information structure
+ * @irq: irq line (unused)
+ * @dev_instance: pointer to our ata_host_set information structure
* @regs: unused
*
+ * Default interrupt handler for PCI IDE devices. Calls
+ * ata_host_intr() for each port that is not disabled.
+ *
* LOCKING:
+ * Obtains host_set lock during operation.
*
* RETURNS:
+ * IRQ_NONE or IRQ_HANDLED.
*
*/
@@ -3381,7 +3455,11 @@ static void ata_host_remove(struct ata_port *ap, unsigned int do_unregister)
* @ent: Probe information provided by low-level driver
* @port_no: Port number associated with this ata_port
*
+ * Initialize a new ata_port structure, and its associated
+ * scsi_host.
+ *
* LOCKING:
+ * Inherited from caller.
*
*/
@@ -3436,9 +3514,13 @@ static void ata_host_init(struct ata_port *ap, struct Scsi_Host *host,
* @host_set: Collections of ports to which we add
* @port_no: Port number associated with this host
*
+ * Attach low-level ATA driver to system.
+ *
* LOCKING:
+ * PCI/etc. bus probe sem.
*
* RETURNS:
+ * New ata_port on success, for NULL on error.
*
*/
@@ -3471,12 +3553,22 @@ err_out:
}
/**
- * ata_device_add -
- * @ent:
+ * ata_device_add - Register hardware device with ATA and SCSI layers
+ * @ent: Probe information describing hardware device to be registered
+ *
+ * This function processes the information provided in the probe
+ * information struct @ent, allocates the necessary ATA and SCSI
+ * host information structures, initializes them, and registers
+ * everything with requisite kernel subsystems.
+ *
+ * This function requests irqs, probes the ATA bus, and probes
+ * the SCSI bus.
*
* LOCKING:
+ * PCI/etc. bus probe sem.
*
* RETURNS:
+ * Number of ports registered. Zero on error (no ports registered).
*
*/
@@ -3755,6 +3847,7 @@ ata_pci_init_legacy_mode(struct pci_dev *pdev, struct ata_port_info **port,
* Inherited from PCI layer (may sleep).
*
* RETURNS:
+ * Zero on success, negative on errno-based value on error.
*
*/
@@ -3974,15 +4067,6 @@ int pci_test_config_bits(struct pci_dev *pdev, struct pci_bits *bits)
#endif /* CONFIG_PCI */
-/**
- * ata_init -
- *
- * LOCKING:
- *
- * RETURNS:
- *
- */
-
static int __init ata_init(void)
{
ata_wq = create_workqueue("ata");

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