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[PATCH] ahci: preserve PORTS_IMPL over host resets 

Instead of writing 0xf blindly, preserve the content of write-once
PORTS_IMPL register over host resets.

This patch is taken from Jeff Garzik's AHCI init update patch.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
This commit is contained in:
Tejun Heo 2006-11-02 12:17:23 +09:00 committed by Jeff Garzik
parent ada406c824
commit 98fa4b60c6
1 changed files with 20 additions and 3 deletions
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23
drivers/ata/ahci.c
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@ -421,6 +421,11 @@ static struct pci_driver ahci_pci_driver = {
};
static inline int ahci_nr_ports(u32 cap)
{
return (cap & 0x1f) + 1;
}
static inline unsigned long ahci_port_base_ul (unsigned long base, unsigned int port)
{
return base + 0x100 + (port * 0x80);
@ -630,11 +635,12 @@ static int ahci_deinit_port(void __iomem *port_mmio, u32 cap, const char **emsg)
static int ahci_reset_controller(void __iomem *mmio, struct pci_dev *pdev)
{
u32 cap_save, tmp;
u32 cap_save, impl_save, tmp;
cap_save = readl(mmio + HOST_CAP);
cap_save &= ( (1<<28) | (1<<17) );
cap_save |= (1 << 27);
impl_save = readl(mmio + HOST_PORTS_IMPL);
/* global controller reset */
tmp = readl(mmio + HOST_CTL);
@ -655,10 +661,21 @@ static int ahci_reset_controller(void __iomem *mmio, struct pci_dev *pdev)
return -EIO;
}
/* turn on AHCI mode */
writel(HOST_AHCI_EN, mmio + HOST_CTL);
(void) readl(mmio + HOST_CTL); /* flush */
/* These write-once registers are normally cleared on reset.
* Restore BIOS values... which we HOPE were present before
* reset.
*/
if (!impl_save) {
impl_save = (1 << ahci_nr_ports(cap_save)) - 1;
dev_printk(KERN_WARNING, &pdev->dev,
"PORTS_IMPL is zero, forcing 0x%x\n", impl_save);
}
writel(cap_save, mmio + HOST_CAP);
writel(0xf, mmio + HOST_PORTS_IMPL);
writel(impl_save, mmio + HOST_PORTS_IMPL);
(void) readl(mmio + HOST_PORTS_IMPL); /* flush */
if (pdev->vendor == PCI_VENDOR_ID_INTEL) {
@ -1467,7 +1484,7 @@ static int ahci_host_init(struct ata_probe_ent *probe_ent)
hpriv->cap = readl(mmio + HOST_CAP);
hpriv->port_map = readl(mmio + HOST_PORTS_IMPL);
probe_ent->n_ports = (hpriv->cap & 0x1f) + 1;
probe_ent->n_ports = ahci_nr_ports(hpriv->cap);
VPRINTK("cap 0x%x port_map 0x%x n_ports %d\n",
hpriv->cap, hpriv->port_map, probe_ent->n_ports);