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Commit 98fa4b60 authored by Tejun Heo's avatar Tejun Heo Committed by Jeff Garzik
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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: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent ada406c8

drivers/ata/ahci.c

+20 −3
Original line number Diff line number Diff line
@@ -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);