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Commit 0baab86b authored by Edward Falk's avatar Edward Falk Committed by Jeff Garzik
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libata: update inline source docs

parent 92bab26b
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Showing with 334 additions and 7 deletions
drivers/scsi/libata-core.c
View file @ 0baab86b
......@@ -186,6 +186,28 @@ static void ata_tf_load_mmio(struct ata_port *ap, struct ata_taskfile *tf)
ata_wait_idle(ap);
}
/**
* ata_tf_load - send taskfile registers to host controller
* @ap: Port to which output is sent
* @tf: ATA taskfile register set
*
* Outputs ATA taskfile to standard ATA host controller using MMIO
* or PIO as indicated by the ATA_FLAG_MMIO flag.
* Writes the control, feature, nsect, lbal, lbam, and lbah registers.
* Optionally (ATA_TFLAG_LBA48) writes hob_feature, hob_nsect,
* hob_lbal, hob_lbam, and hob_lbah.
*
* This function waits for idle (!BUSY and !DRQ) after writing
* registers. If the control register has a new value, this
* function also waits for idle after writing control and before
* writing the remaining registers.
*
* May be used as the tf_load() entry in ata_port_operations.
*
* LOCKING:
* Inherited from caller.
*/
void ata_tf_load(struct ata_port *ap, struct ata_taskfile *tf)
{
if (ap->flags & ATA_FLAG_MMIO)
......@@ -195,11 +217,11 @@ void ata_tf_load(struct ata_port *ap, struct ata_taskfile *tf)
}
/**
* ata_exec_command - issue ATA command to host controller
* ata_exec_command_pio - issue ATA command to host controller
* @ap: port to which command is being issued
* @tf: ATA taskfile register set
*
* Issues PIO/MMIO write to ATA command register, with proper
* Issues PIO write to ATA command register, with proper
* synchronization with interrupt handler / other threads.
*
* LOCKING:
......@@ -235,6 +257,18 @@ static void ata_exec_command_mmio(struct ata_port *ap, struct ata_taskfile *tf)
ata_pause(ap);
}
/**
* ata_exec_command - issue ATA command to host controller
* @ap: port to which command is being issued
* @tf: ATA taskfile register set
*
* Issues PIO/MMIO write to ATA command register, with proper
* synchronization with interrupt handler / other threads.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
void ata_exec_command(struct ata_port *ap, struct ata_taskfile *tf)
{
if (ap->flags & ATA_FLAG_MMIO)
......@@ -305,7 +339,7 @@ void ata_tf_to_host_nolock(struct ata_port *ap, struct ata_taskfile *tf)
}
/**
* ata_tf_read - input device's ATA taskfile shadow registers
* ata_tf_read_pio - input device's ATA taskfile shadow registers
* @ap: Port from which input is read
* @tf: ATA taskfile register set for storing input
*
......@@ -368,6 +402,23 @@ static void ata_tf_read_mmio(struct ata_port *ap, struct ata_taskfile *tf)
}
}
/**
* ata_tf_read - input device's ATA taskfile shadow registers
* @ap: Port from which input is read
* @tf: ATA taskfile register set for storing input
*
* Reads ATA taskfile registers for currently-selected device
* into @tf.
*
* Reads nsect, lbal, lbam, lbah, and device. If ATA_TFLAG_LBA48
* is set, also reads the hob registers.
*
* May be used as the tf_read() entry in ata_port_operations.
*
* LOCKING:
* Inherited from caller.
*/
void ata_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
{
if (ap->flags & ATA_FLAG_MMIO)
......@@ -381,7 +432,7 @@ void ata_tf_read(struct ata_port *ap, struct ata_taskfile *tf)
* @ap: port where the device is
*
* Reads ATA taskfile status register for currently-selected device
* and return it's value. This also clears pending interrupts
* and return its value. This also clears pending interrupts
* from this device
*
* LOCKING:
......@@ -397,7 +448,7 @@ static u8 ata_check_status_pio(struct ata_port *ap)
* @ap: port where the device is
*
* Reads ATA taskfile status register for currently-selected device
* via MMIO and return it's value. This also clears pending interrupts
* via MMIO and return its value. This also clears pending interrupts
* from this device
*
* LOCKING:
......@@ -408,6 +459,20 @@ static u8 ata_check_status_mmio(struct ata_port *ap)
return readb((void __iomem *) ap->ioaddr.status_addr);
}
/**
* ata_check_status - Read device status reg & clear interrupt
* @ap: port where the device is
*
* Reads ATA taskfile status register for currently-selected device
* and return its value. This also clears pending interrupts
* from this device
*
* May be used as the check_status() entry in ata_port_operations.
*
* LOCKING:
* Inherited from caller.
*/
u8 ata_check_status(struct ata_port *ap)
{
if (ap->flags & ATA_FLAG_MMIO)
......@@ -415,6 +480,20 @@ u8 ata_check_status(struct ata_port *ap)
return ata_check_status_pio(ap);
}
/**
* ata_altstatus - Read device alternate status reg
* @ap: port where the device is
*
* Reads ATA taskfile alternate status register for
* currently-selected device and return its value.
*
* Note: may NOT be used as the check_altstatus() entry in
* ata_port_operations.
*
* LOCKING:
* Inherited from caller.
*/
u8 ata_altstatus(struct ata_port *ap)
{
if (ap->ops->check_altstatus)
......@@ -425,6 +504,20 @@ u8 ata_altstatus(struct ata_port *ap)
return inb(ap->ioaddr.altstatus_addr);
}
/**
* ata_chk_err - Read device error reg
* @ap: port where the device is
*
* Reads ATA taskfile error register for
* currently-selected device and return its value.
*
* Note: may NOT be used as the check_err() entry in
* ata_port_operations.
*
* LOCKING:
* Inherited from caller.
*/
u8 ata_chk_err(struct ata_port *ap)
{
if (ap->ops->check_err)
......@@ -873,10 +966,24 @@ void ata_dev_id_string(u16 *id, unsigned char *s,
}
}
/**
* ata_noop_dev_select - Select device 0/1 on ATA bus
* @ap: ATA channel to manipulate
* @device: ATA device (numbered from zero) to select
*
* This function performs no actual function.
*
* May be used as the dev_select() entry in ata_port_operations.
*
* LOCKING:
* caller.
*/
void ata_noop_dev_select (struct ata_port *ap, unsigned int device)
{
}
/**
* ata_std_dev_select - Select device 0/1 on ATA bus
* @ap: ATA channel to manipulate
......@@ -884,7 +991,9 @@ void ata_noop_dev_select (struct ata_port *ap, unsigned int device)
*
* Use the method defined in the ATA specification to
* make either device 0, or device 1, active on the
* ATA channel.
* ATA channel. Works with both PIO and MMIO.
*
* May be used as the dev_select() entry in ata_port_operations.
*
* LOCKING:
* caller.
......@@ -2127,6 +2236,19 @@ void ata_qc_prep(struct ata_queued_cmd *qc)
* spin_lock_irqsave(host_set lock)
*/
/**
* ata_sg_init_one - Prepare a one-entry scatter-gather list.
* @qc: Queued command
* @buf: transfer buffer
* @buflen: length of buf
*
* Builds a single-entry scatter-gather list to initiate a
* transfer utilizing the specified buffer.
*
* LOCKING:
*/
void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf, unsigned int buflen)
{
struct scatterlist *sg;
......@@ -2158,6 +2280,18 @@ void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf, unsigned int buflen)
* spin_lock_irqsave(host_set lock)
*/
/**
* ata_sg_init - Assign a scatter gather list to a queued command
* @qc: Queued command
* @sg: Scatter-gather list
* @n_elem: length of sg list
*
* Attaches a scatter-gather list to a queued command.
*
* LOCKING:
*/
void ata_sg_init(struct ata_queued_cmd *qc, struct scatterlist *sg,
unsigned int n_elem)
{
......@@ -2331,6 +2465,18 @@ static void ata_pio_complete (struct ata_port *ap)
ata_qc_complete(qc, drv_stat);
}
/**
* swap_buf_le16 -
* @buf: Buffer to swap
* @buf_words: Number of 16-bit words in buffer.
*
* Swap halves of 16-bit words if needed to convert from
* little-endian byte order to native cpu byte order, or
* vice-versa.
*
* LOCKING:
*/
void swap_buf_le16(u16 *buf, unsigned int buf_words)
{
#ifdef __BIG_ENDIAN
......@@ -2992,6 +3138,7 @@ int ata_qc_issue(struct ata_queued_cmd *qc)
return -1;
}
/**
* ata_qc_issue_prot - issue taskfile to device in proto-dependent manner
* @qc: command to issue to device
......@@ -3001,6 +3148,8 @@ int ata_qc_issue(struct ata_queued_cmd *qc)
* classes called "protocols", and issuing each type of protocol
* is slightly different.
*
* May be used as the qc_issue() entry in ata_port_operations.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*
......@@ -3058,7 +3207,7 @@ int ata_qc_issue_prot(struct ata_queued_cmd *qc)
}
/**
* ata_bmdma_setup - Set up PCI IDE BMDMA transaction
* ata_bmdma_setup_mmio - Set up PCI IDE BMDMA transaction
* @qc: Info associated with this ATA transaction.
*
* LOCKING:
......@@ -3165,6 +3314,18 @@ static void ata_bmdma_start_pio (struct ata_queued_cmd *qc)
ap->ioaddr.bmdma_addr + ATA_DMA_CMD);
}
/**
* ata_bmdma_start - Start a PCI IDE BMDMA transaction
* @qc: Info associated with this ATA transaction.
*
* Writes the ATA_DMA_START flag to the DMA command register.
*
* May be used as the bmdma_start() entry in ata_port_operations.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
void ata_bmdma_start(struct ata_queued_cmd *qc)
{
if (qc->ap->flags & ATA_FLAG_MMIO)
......@@ -3173,6 +3334,20 @@ void ata_bmdma_start(struct ata_queued_cmd *qc)
ata_bmdma_start_pio(qc);
}
/**
* ata_bmdma_setup - Set up PCI IDE BMDMA transaction
* @qc: Info associated with this ATA transaction.
*
* Writes address of PRD table to device's PRD Table Address
* register, sets the DMA control register, and calls
* ops->exec_command() to start the transfer.
*
* May be used as the bmdma_setup() entry in ata_port_operations.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
void ata_bmdma_setup(struct ata_queued_cmd *qc)
{
if (qc->ap->flags & ATA_FLAG_MMIO)
......@@ -3181,6 +3356,19 @@ void ata_bmdma_setup(struct ata_queued_cmd *qc)
ata_bmdma_setup_pio(qc);
}
/**
* ata_bmdma_irq_clear - Clear PCI IDE BMDMA interrupt.
* @qc: Info associated with this ATA transaction.
*
* Clear interrupt and error flags in DMA status register.
*
* May be used as the irq_clear() entry in ata_port_operations.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
void ata_bmdma_irq_clear(struct ata_port *ap)
{
if (ap->flags & ATA_FLAG_MMIO) {
......@@ -3193,6 +3381,19 @@ void ata_bmdma_irq_clear(struct ata_port *ap)
}
/**
* ata_bmdma_status - Read PCI IDE BMDMA status
* @qc: Info associated with this ATA transaction.
*
* Read and return BMDMA status register.
*
* May be used as the bmdma_status() entry in ata_port_operations.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
u8 ata_bmdma_status(struct ata_port *ap)
{
u8 host_stat;
......@@ -3204,6 +3405,19 @@ u8 ata_bmdma_status(struct ata_port *ap)
return host_stat;
}
/**
* ata_bmdma_stop - Stop PCI IDE BMDMA transfer
* @qc: Info associated with this ATA transaction.
*
* Clears the ATA_DMA_START flag in the dma control register
*
* May be used as the bmdma_stop() entry in ata_port_operations.
*
* LOCKING:
* spin_lock_irqsave(host_set lock)
*/
void ata_bmdma_stop(struct ata_port *ap)
{
if (ap->flags & ATA_FLAG_MMIO) {
......@@ -3407,6 +3621,19 @@ static void atapi_packet_task(void *_data)
ata_qc_complete(qc, ATA_ERR);
}
/**
* ata_port_start - Set port up for dma.
* @ap: Port to initialize
*
* Called just after data structures for each port are
* initialized. Allocates space for PRD table.
*
* May be used as the port_start() entry in ata_port_operations.
*
* LOCKING:
*/
int ata_port_start (struct ata_port *ap)
{
struct device *dev = ap->host_set->dev;
......@@ -3420,6 +3647,18 @@ int ata_port_start (struct ata_port *ap)
return 0;
}
/**
* ata_port_stop - Undo ata_port_start()
* @ap: Port to shut down
*
* Frees the PRD table.
*
* May be used as the port_stop() entry in ata_port_operations.
*
* LOCKING:
*/
void ata_port_stop (struct ata_port *ap)
{
struct device *dev = ap->host_set->dev;
......@@ -3720,7 +3959,15 @@ int ata_scsi_release(struct Scsi_Host *host)
/**
* ata_std_ports - initialize ioaddr with standard port offsets.
* @ioaddr: IO address structure to be initialized
*
* Utility function which initializes data_addr, error_addr,
* feature_addr, nsect_addr, lbal_addr, lbam_addr, lbah_addr,
* device_addr, status_addr, and command_addr to standard offsets
* relative to cmd_addr.
*
* Does not set ctl_addr, altstatus_addr, bmdma_addr, or scr_addr.
*/
void ata_std_ports(struct ata_ioports *ioaddr)
{
ioaddr->data_addr = ioaddr->cmd_addr + ATA_REG_DATA;
......@@ -3762,6 +4009,20 @@ ata_probe_ent_alloc(struct device *dev, struct ata_port_info *port)
return probe_ent;
}
/**
* ata_pci_init_native_mode - Initialize native-mode driver
* @pdev: pci device to be initialized
* @port: array[2] of pointers to port info structures.
*
* Utility function which allocates and initializes an
* ata_probe_ent structure for a standard dual-port
* PIO-based IDE controller. The returned ata_probe_ent
* structure can be passed to ata_device_add(). The returned
* ata_probe_ent structure should then be freed with kfree().
*/
#ifdef CONFIG_PCI
struct ata_probe_ent *
ata_pci_init_native_mode(struct pci_dev *pdev, struct ata_port_info **port)
......@@ -3843,6 +4104,14 @@ ata_pci_init_legacy_mode(struct pci_dev *pdev, struct ata_port_info **port,
* @port_info: Information from low-level host driver
* @n_ports: Number of ports attached to host controller
*
* This is a helper function which can be called from a driver's
* xxx_init_one() probe function if the hardware uses traditional
* IDE taskfile registers.
*
* This function calls pci_enable_device(), reserves its register
* regions, sets the dma mask, enables bus master mode, and calls
* ata_device_add()
*
* LOCKING:
* Inherited from PCI layer (may sleep).
*
......
include/linux/libata.h
View file @ 0baab86b
......@@ -466,12 +466,34 @@ static inline u8 ata_chk_status(struct ata_port *ap)
return ap->ops->check_status(ap);
}
/**
* ata_pause - Flush writes and pause 400 nanoseconds.
* @ap: Port to wait for.
*
* LOCKING:
* Inherited from caller.
*/
static inline void ata_pause(struct ata_port *ap)
{
ata_altstatus(ap);
ndelay(400);
}
/**
* ata_busy_wait - Wait for a port status register
* @ap: Port to wait for.
*
* Waits up to max*10 microseconds for the selected bits in the port's
* status register to be cleared.
* Returns final value of status register.
*
* LOCKING:
* Inherited from caller.
*/
static inline u8 ata_busy_wait(struct ata_port *ap, unsigned int bits,
unsigned int max)
{
......@@ -486,6 +508,18 @@ static inline u8 ata_busy_wait(struct ata_port *ap, unsigned int bits,
return status;
}
/**
* ata_wait_idle - Wait for a port to be idle.
* @ap: Port to wait for.
*
* Waits up to 10ms for port's BUSY and DRQ signals to clear.
* Returns final value of status register.
*
* LOCKING:
* Inherited from caller.
*/
static inline u8 ata_wait_idle(struct ata_port *ap)
{
u8 status = ata_busy_wait(ap, ATA_BUSY | ATA_DRQ, 1000);
......@@ -524,6 +558,18 @@ static inline void ata_tf_init(struct ata_port *ap, struct ata_taskfile *tf, uns
tf->device = ATA_DEVICE_OBS | ATA_DEV1;
}
/**
* ata_irq_on - Enable interrupts on a port.
* @ap: Port on which interrupts are enabled.
*
* Enable interrupts on a legacy IDE device using MMIO or PIO,
* wait for idle, clear any pending interrupts.
*
* LOCKING:
* Inherited from caller.
*/
static inline u8 ata_irq_on(struct ata_port *ap)
{
struct ata_ioports *ioaddr = &ap->ioaddr;
......@@ -543,6 +589,18 @@ static inline u8 ata_irq_on(struct ata_port *ap)
return tmp;
}
/**
* ata_irq_ack - Acknowledge a device interrupt.
* @ap: Port on which interrupts are enabled.
*
* Wait up to 10 ms for legacy IDE device to become idle (BUSY
* or BUSY+DRQ clear). Obtain dma status and port status from
* device. Clear the interrupt. Return port status.
*
* LOCKING:
*/
static inline u8 ata_irq_ack(struct ata_port *ap, unsigned int chk_drq)
{
unsigned int bits = chk_drq ? ATA_BUSY | ATA_DRQ : ATA_BUSY;
......
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