[PATCH v3] libata: pata_samsung_cf: Add Samsung PATA controller driver

[kgene.kim@samsung.com (Kukjin Kim)]

Sergei Shtylyov wrote:
> 
> Hello.
> 
> Kukjin Kim wrote:
> 
> >>> From: Abhilash Kesavan <a.kesavan@samsung.com>
> >>> Adds support for the Samsung PATA controller. This driver is based on
the
> >>> Libata subsystem and references the earlier patches sent for IDE
subsystem.
> 
> > Hi,
> 
> > Thanks for your comments.
> 
> >>> Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
> >>> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
> >> [...]
> 
> >>> diff --git a/drivers/ata/pata_samsung_cf.c
b/drivers/ata/pata_samsung_cf.c
> >>> new file mode 100644
> >>> index 0000000..fef5515
> >>> --- /dev/null
> >>> +++ b/drivers/ata/pata_samsung_cf.c
> >>> @@ -0,0 +1,608 @@
> >>> +/* linux/drivers/ata/pata_samsung_cf.c
> 
> >>     File names in the heading comment are discouraged.
> 
> > Hmm. I used like that in other device drivers.
> 
>     Nevertheless, it's quite an old rule already.
> 
> > Ok..will remove the file name in the heading comment.
> 
> >> [...]
> 
> >>> +
> >>> +	piotime = (t2i << 12) | (t2 << 4) | t1;
> >>> +
> >>> +	return piotime;
> >>> +}
> >>> +
> >>> +static void pata_s3c_set_piomode(struct ata_port *ap, struct
ata_device
> *adev)
> >>> +{
> >>> +	int mode = adev->pio_mode - XFER_PIO_0;
> >>> +	struct s3c_ide_info *info = ap->host->private_data;
> >>> +	ulong ata_cfg = readl(info->ide_addr + S3C_ATA_CFG);
> >>> +	ulong piotime;
> >>> +
> >>> +	/* Calculates timing parameters for PIO mode */
> >>> +	piotime = pata_s3c_setup_timing(info, adev);
> 
> >>     In fact, for 8-bit (command) timing you should program the slowest
mode
> of
> >> the two drives. However, with CF, you probably only have only one drive
per
> >> channel...
> 
> > Below code looks OK ?
> 
>     No, it doesn't.
> 
> > 	if (ata_timing_compute(adev, adev->pio_mode, &timing, cycle_time, 0))
> > {
> > 		dev_err(ap->dev, "Failed to compute ATA timing\n");
> > 		piotime = pata_s3c_setup_timing(info, &initial_timing);
> > 	} else {
> > 		piotime = pata_s3c_setup_timing(info, &timing);
> > 	}
> > where initial_timing is for PIO0. I have added the below struct
> 
> > static const struct ata_timing initial_timing =
> > 	{XFER_PIO_0, 70, 290, 240, 600, 165, 150, 0, 600, 0};
> 
>     I'd call ata_timing_find_mode(XFER_PIO_0) rather than duplicating the
> ata_timing entry. But really, you shouldn't set any timing for an invalid
mode
> and, as I said, you won't be passed one, so there's nor much sense in
calling
> ata_timing_compute() and checking its result; anyway, you'd want to call
> ata_timing_find_mode() here instead of ata_timing_compute() because the
latter
> returns already quantized timings, but initial_timing is not quantized,
you'll
> have to call ata_timing_compute() in pata_s3c_setup_timing() anyway.
> 
OK, no check for invalid mode then. Now using 'ata_timing_compute' to get the
quantized timings t1, t2 and t2i and then writing them to PIO_TIME registers.
PIO_TIME [0:3]  t1      [4:11] t2      [12:19] t2i.

> >>> +
> >>> +	/* Enables IORDY if mode requires it */
> >>> +	if (ata_pio_need_iordy(adev))
> >>> +		ata_cfg |= S3C_ATA_CFG_IORDYEN;
> >>> +	else
> >>> +		ata_cfg &= ~S3C_ATA_CFG_IORDYEN;
> >>> +
> >>> +	/* Host controller supports upto PIO4 only */
> >>> +	if (mode >= 0 && mode <= 4) {
> 
> >>     No need to check -- you won't be passed a mode not specified by your
> >> pio_mask.
> 
> > Will remove the check.
> 
> >>> +static int __devinit pata_s3c_probe(struct platform_device *pdev)
> [...]
> >>> +	if (!request_mem_region(res->start, resource_size(res), DRV_NAME)) {
> 
> >>     Probably should call devm_request_mem_region() if you're using
> >> devm_ioremap()...
> 
> > Will change to devm_request_mem_region.
> 
>     This function does exist, if I don't mistake...
> 
> >>> +release_mem:
> >>> +	release_mem_region(res->start, resource_size(res));
> >>> +release_device_mem:
> >>> +	kfree(info);
> 
> >>     Doesn't using devm_kzalloc() guarantee that the memory will be freed
up
> >> automatically?
> 
> > Will remove kfree and release_mem_region because of devm_kzalloc and
> > devm_request_mem_region usage
> 
>     I don't know devres librarry capabilities well. Tejun, am I right?
> 
> >>> +static struct platform_driver pata_s3c_driver = {
> >>> +	.probe		= pata_s3c_probe,
> >>>
> >>>
> 
> >>     2 empty lines -- broken patch?
> 
> > Seems OK at my end.
> 
>     The sent patch had them, nevertheless.
> 
> MBR, Sergei


Thanks.

Best regards,
Kgene.
--
Kukjin Kim <kgene.kim@samsung.com>, Senior Engineer,
SW Solution Development Team, Samsung Electronics Co., Ltd.