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ata: pata_of_platform: Allow to use 16-bit wide data transfer 

In some cases, the system bus can be configured for 16-bit mode,
in this case using read/write functions for 32-bit values
results in two cycles of 16 bits each, which is wrong.
This patch adds the devicetree flag to switch the driver to
use 16-bit mode for I/O transfers.

Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Alexander Shiyan 2019-01-19 07:52:01 +03:00 committed by Jens Axboe
parent 740c68a0cd
commit f3d5e4f18d
3 changed files with 19 additions and 12 deletions
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6
drivers/ata/pata_of_platform.c
View File

@ -32,6 +32,7 @@ static int pata_of_platform_probe(struct platform_device *ofdev)
unsigned int reg_shift = 0;
int pio_mode = 0;
int pio_mask;
bool use16bit;
ret = of_address_to_resource(dn, 0, &io_res);
if (ret) {
@ -60,11 +61,14 @@ static int pata_of_platform_probe(struct platform_device *ofdev)
dev_info(&ofdev->dev, "pio-mode unspecified, assuming PIO0\n");
}
use16bit = of_property_read_bool(dn, "ata-generic,use16bit");
pio_mask = 1 << pio_mode;
pio_mask |= (1 << pio_mode) - 1;
return __pata_platform_probe(&ofdev->dev, &io_res, &ctl_res, irq_res,
reg_shift, pio_mask, &pata_platform_sht);
reg_shift, pio_mask, &pata_platform_sht,
use16bit);
}
static const struct of_device_id pata_of_platform_match[] = {

22
drivers/ata/pata_platform.c
View File

@ -47,13 +47,6 @@ static struct scsi_host_template pata_platform_sht = {
ATA_PIO_SHT(DRV_NAME),
};
static struct ata_port_operations pata_platform_port_ops = {
.inherits = &ata_sff_port_ops,
.sff_data_xfer = ata_sff_data_xfer32,
.cable_detect = ata_cable_unknown,
.set_mode = pata_platform_set_mode,
};
static void pata_platform_setup_port(struct ata_ioports *ioaddr,
unsigned int shift)
{
@ -79,6 +72,7 @@ static void pata_platform_setup_port(struct ata_ioports *ioaddr,
* @ioport_shift: I/O port shift
* @__pio_mask: PIO mask
* @sht: scsi_host_template to use when registering
* @use16bit: Flag to indicate 16-bit IO instead of 32-bit
*
* Register a platform bus IDE interface. Such interfaces are PIO and we
* assume do not support IRQ sharing.
@ -101,7 +95,7 @@ static void pata_platform_setup_port(struct ata_ioports *ioaddr,
int __pata_platform_probe(struct device *dev, struct resource *io_res,
struct resource *ctl_res, struct resource *irq_res,
unsigned int ioport_shift, int __pio_mask,
struct scsi_host_template *sht)
struct scsi_host_template *sht, bool use16bit)
{
struct ata_host *host;
struct ata_port *ap;
@ -131,7 +125,15 @@ int __pata_platform_probe(struct device *dev, struct resource *io_res,
return -ENOMEM;
ap = host->ports[0];
ap->ops = &pata_platform_port_ops;
ap->ops = devm_kzalloc(dev, sizeof(*ap->ops), GFP_KERNEL);
ap->ops->inherits = &ata_sff_port_ops;
ap->ops->cable_detect = ata_cable_unknown;
ap->ops->set_mode = pata_platform_set_mode;
if (use16bit)
ap->ops->sff_data_xfer = ata_sff_data_xfer;
else
ap->ops->sff_data_xfer = ata_sff_data_xfer32;
ap->pio_mask = __pio_mask;
ap->flags |= ATA_FLAG_SLAVE_POSS;
@ -218,7 +220,7 @@ static int pata_platform_probe(struct platform_device *pdev)
return __pata_platform_probe(&pdev->dev, io_res, ctl_res, irq_res,
pp_info ? pp_info->ioport_shift : 0,
pio_mask, &pata_platform_sht);
pio_mask, &pata_platform_sht, false);
}
static struct platform_driver pata_platform_driver = {

3
include/linux/ata_platform.h
View File

@ -19,7 +19,8 @@ extern int __pata_platform_probe(struct device *dev,
struct resource *irq_res,
unsigned int ioport_shift,
int __pio_mask,
struct scsi_host_template *sht);
struct scsi_host_template *sht,
bool use16bit);
/*
* Marvell SATA private data