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Commit 15fe982e authored by Tejun Heo's avatar Tejun Heo Committed by Jeff Garzik
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ahci: retry enabling AHCI a few times before spitting out WARN_ON() 



Some chips need AHCI_EN set more than once to actually set it.  Try a
few times before giving up and spitting out WARN_ON().

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Cc: Peer Chen <pchen@nvidia.com>
Cc: Volker Armin Hemmann <volker.armin.hemmann@tu-clausthal.de>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent 411cb386

drivers/ata/ahci.c

+13 −2
Original line number Diff line number Diff line
@@ -556,16 +556,27 @@ static inline void __iomem *ahci_port_base(struct ata_port *ap) 


static void ahci_enable_ahci(void __iomem *mmio)

{

	int i;

	u32 tmp;



	/* turn on AHCI_EN */

	tmp = readl(mmio + HOST_CTL);

	if (!(tmp & HOST_AHCI_EN)) {

	if (tmp & HOST_AHCI_EN)

		return;



	/* Some controllers need AHCI_EN to be written multiple times.

	 * Try a few times before giving up.

	 */

	for (i = 0; i < 5; i++) {

		tmp |= HOST_AHCI_EN;

		writel(tmp, mmio + HOST_CTL);

		tmp = readl(mmio + HOST_CTL);	/* flush && sanity check */

		WARN_ON(!(tmp & HOST_AHCI_EN));

		if (tmp & HOST_AHCI_EN)

			return;

		msleep(10);

	}



	WARN_ON(1);

}



/**