[PATCH v4] libata: pata_samsung_cf: Add Samsung PATA controller driver
Sergei Shtylyov
sshtylyov at mvista.com
Mon Jun 28 06:12:06 EDT 2010
Hello.
Kukjin Kim wrote:
> From: Abhilash Kesavan <a.kesavan at 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.
> Signed-off-by: Abhilash Kesavan <a.kesavan at samsung.com>
> Signed-off-by: Kukjin Kim <kgene.kim at samsung.com>
[...]
> diff --git a/drivers/ata/pata_samsung_cf.c b/drivers/ata/pata_samsung_cf.c
> new file mode 100644
> index 0000000..aeb2825
> --- /dev/null
> +++ b/drivers/ata/pata_samsung_cf.c
> @@ -0,0 +1,735 @@
[...]
> +static unsigned long
> +pata_s3c_setup_timing(struct s3c_ide_info *info, const struct ata_timing *ata)
> +{
> + int t1;
> + int t2;
> + int t2i;
> + ulong piotime;
> +
> + t1 = ata->setup;
> + t2 = ata->act8b;
> + t2i = ata->rec8b;
Could be initializers...
[...]
> +/*
> + * pata_s3c_data_xfer - Transfer data by PIO
> + */
> +unsigned int pata_s3c_data_xfer(struct ata_device *dev, unsigned char *buf,
> + unsigned int buflen, int rw)
> +{
> + struct ata_port *ap = dev->link->ap;
> + struct s3c_ide_info *info = ap->host->private_data;
> + void __iomem *data_addr = ap->ioaddr.data_addr;
> + unsigned int words = buflen >> 1, i;
> + u16 *data_ptr = (u16 *)buf;
> +
> + /* Requires wait same as in ata_inb/ata_outb */
> + if (rw == READ)
> + for (i = 0; i < words; i++, data_ptr++) {
> + wait_for_host_ready(info);
> + (void) readw(data_addr);
> + wait_for_host_ready(info);
> + *data_ptr = readw(info->ide_addr
> + + S3C_ATA_PIO_RDATA);
> + }
> + else
> + for (i = 0; i < words; i++, data_ptr++) {
> + wait_for_host_ready(info);
> + writew(*data_ptr, data_addr);
> + }
> +
> + if (buflen & 0x01) {
> + dev_err(ap->dev, "unexpected trailing data\n");
> + return -EINVAL;
This method should return number of bytes consumed, never error...
> + }
> +
> + return words << 1;
> +}
[...]
> +/*
> + * pata_s3c_devchk - PATA device presence detection
> + */
> +static unsigned int pata_s3c_devchk(struct ata_port *ap,
> + unsigned int device)
> +{
> + struct ata_ioports *ioaddr = &ap->ioaddr;
> + u8 nsect, lbal;
> +
> + ap->ops->sff_dev_select(ap, device);
Can call pata_s3c_dev_select() directly...
> +/*
> + * pata_s3c_wait_after_reset - wait for devices to become ready after reset
> + */
> +static int pata_s3c_wait_after_reset(struct ata_link *link,
> + unsigned int devmask, unsigned long deadline)
> +{
> + struct ata_port *ap = link->ap;
> + struct ata_ioports *ioaddr = &ap->ioaddr;
> + unsigned int dev0 = devmask & (1 << 0);
> + unsigned int dev1 = devmask & (1 << 1);
> + int rc, ret = 0;
> +
> + msleep(ATA_WAIT_AFTER_RESET);
> +
> + /* always check readiness of the master device */
> + rc = ata_sff_wait_ready(link, deadline);
> + if (rc)
> + return rc;
> +
> + /* if device 1 was found in ata_devchk, wait for register
> + * access briefly, then wait for BSY to clear.
> + */
> + if (dev1) {
> + int i;
> +
> + ap->ops->sff_dev_select(ap, 1);
Ditto.
> +
> + for (i = 0; i < 2; i++) {
> + u8 nsect, lbal;
> +
> + nsect = ata_inb(ap->host, ioaddr->nsect_addr);
> + lbal = ata_inb(ap->host, ioaddr->lbal_addr);
> + if ((nsect == 1) && (lbal == 1))
> + break;
> + msleep(50); /* give drive a breather */
> + }
> +
> + rc = ata_sff_wait_ready(link, deadline);
> + if (rc) {
> + if (rc != -ENODEV)
> + return rc;
> + ret = rc;
> + }
> + }
> +
Should have copied the original commant here, cause I dount that this
drive selection trickery is indeed necessary...
> + ap->ops->sff_dev_select(ap, 0);
> + if (dev1)
> + ap->ops->sff_dev_select(ap, 1);
> + if (dev0)
> + ap->ops->sff_dev_select(ap, 0);
Ditto.
> +/*
> + * pata_s3c_softreset - reset host port via ATA SRST
> + */
> +static int pata_s3c_softreset(struct ata_link *link, unsigned int *classes,
> + unsigned long deadline)
> +{
> + struct ata_port *ap = link->ap;
> + unsigned int slave_possible = ap->flags & ATA_FLAG_SLAVE_POSS;
I don't see where you set this flag, hence the check seems useless.
> + unsigned int devmask = 0;
> + int rc;
> + u8 err;
> +
> + /* determine if device 0/1 are present */
> + if (pata_s3c_devchk(ap, 0))
> + devmask |= (1 << 0);
> + if (slave_possible && pata_s3c_devchk(ap, 1))
> + devmask |= (1 << 1);
> +
> + /* select device 0 again */
> + ap->ops->sff_dev_select(ap, 0);
Can call pata_s3c_dev_select() directly...
> +
> + /* issue bus reset */
> + rc = pata_s3c_bus_softreset(ap, devmask, deadline);
> + /* if link is occupied, -ENODEV too is an error */
> + if (rc && (rc != -ENODEV || sata_scr_valid(link))) {
sata_scr_valid() doesn't apply to your PATA driver, no need to call it.
> +static void pata_s3c_hwinit(struct s3c_ide_info *info,
> + struct s3c_ide_platdata *pdata)
> +{
> + switch (info->cpu_type) {
> + case TYPE_S3C64XX:
> + /* Configure as big endian */
> + pata_s3c_cfg_mode(info->sfr_addr);
> + pata_s3c_set_endian(info->ide_addr, 1);
> + pata_s3c_enable(info->ide_addr, true);
> + msleep(100);
> +
> + /* Remove IRQ Status */
> + writel(0x1f, info->ide_addr + S3C_ATA_IRQ);
> + writel(0x1b, info->ide_addr + S3C_ATA_IRQ_MSK);
> + break;
Mis-indented: one more tab needed.
> +
> + case TYPE_S5PC100:
> + pata_s3c_cfg_mode(info->sfr_addr);
There should be a comment like /* FALLTHRU */ if *break* is omitted.
> + case TYPE_S5PV210:
> + /* Configure as little endian */
> + pata_s3c_set_endian(info->ide_addr, 0);
> + pata_s3c_enable(info->ide_addr, true);
> + msleep(100);
> +
> + /* Remove IRQ Status */
> + writel(0x3f, info->ide_addr + S3C_ATA_IRQ);
> + writel(0x3f, info->ide_addr + S3C_ATA_IRQ_MSK);
> + break;
Mis-indented.
> +static int __devinit pata_s3c_probe(struct platform_device *pdev)
Is this device really hot-pluggable? Shouldn't this be '__init' instead?
> +{
> + struct s3c_ide_platdata *pdata = pdev->dev.platform_data;
> + struct device *dev = &pdev->dev;
> + struct s3c_ide_info *info;
> + struct resource *res;
> + struct ata_port *ap;
> + struct ata_host *host;
> + enum s3c_cpu_type cpu_type;
> + int ret;
> +
> + cpu_type = platform_get_device_id(pdev)->driver_data;
> +
> + info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
> + if (!info) {
> + dev_err(dev, "failed to allocate memory for device data\n");
> + return -ENOMEM;
> + }
> +
> + info->irq = platform_get_irq(pdev, 0);
> + if (info->irq < 0) {
> + dev_err(dev, "could not obtain irq number\n");
You driver permits working without IRQ -- why require an IRQ resource even
if there's no IRQ?
[...]
> + if (!info->irq) {
Should be (info->irq <= 0) instead, I think, with the above check removed.
> + ap->flags |= ATA_FLAG_PIO_POLLING;
> + ata_port_desc(ap, "no IRQ, using PIO polling\n");
> + }
> +
[...]
> +static struct platform_driver pata_s3c_driver = {
> + .probe = pata_s3c_probe,
If this function will be '__init', this needs to be removed.
[...]
> +static int __init pata_s3c_init(void)
> +{
> + return platform_driver_register(&pata_s3c_driver);
I'd coinsider platform_driver_probe() -- this device doesn't seem to be
hot-pluggable...
MBR, Sergei
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