linux/drivers/ata/pata_of_platform.c
Alexander Shiyan f3d5e4f18d 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>
2019-02-08 06:42:53 -07:00

94 lines
2.3 KiB
C

/*
* OF-platform PATA driver
*
* Copyright (c) 2007 MontaVista Software, Inc.
* Anton Vorontsov <avorontsov@ru.mvista.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License (Version 2) as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/ata_platform.h>
#include <linux/libata.h>
#define DRV_NAME "pata_of_platform"
static struct scsi_host_template pata_platform_sht = {
ATA_PIO_SHT(DRV_NAME),
};
static int pata_of_platform_probe(struct platform_device *ofdev)
{
int ret;
struct device_node *dn = ofdev->dev.of_node;
struct resource io_res;
struct resource ctl_res;
struct resource *irq_res;
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) {
dev_err(&ofdev->dev, "can't get IO address from "
"device tree\n");
return -EINVAL;
}
ret = of_address_to_resource(dn, 1, &ctl_res);
if (ret) {
dev_err(&ofdev->dev, "can't get CTL address from "
"device tree\n");
return -EINVAL;
}
irq_res = platform_get_resource(ofdev, IORESOURCE_IRQ, 0);
of_property_read_u32(dn, "reg-shift", &reg_shift);
if (!of_property_read_u32(dn, "pio-mode", &pio_mode)) {
if (pio_mode > 6) {
dev_err(&ofdev->dev, "invalid pio-mode\n");
return -EINVAL;
}
} else {
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,
use16bit);
}
static const struct of_device_id pata_of_platform_match[] = {
{ .compatible = "ata-generic", },
{ },
};
MODULE_DEVICE_TABLE(of, pata_of_platform_match);
static struct platform_driver pata_of_platform_driver = {
.driver = {
.name = DRV_NAME,
.of_match_table = pata_of_platform_match,
},
.probe = pata_of_platform_probe,
.remove = ata_platform_remove_one,
};
module_platform_driver(pata_of_platform_driver);
MODULE_DESCRIPTION("OF-platform PATA driver");
MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
MODULE_LICENSE("GPL");