Messages in this thread | | | Date | Fri, 21 Sep 2007 12:31:20 +0200 | From | Jens Axboe <> | Subject | Re: [PATCH] ahci: enable GHC.AE bit before set GHC.HR |
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On Fri, Sep 21 2007, Peer Chen wrote: > According to the description of section 5.2.2.1 and 10.1.2 of AHCI specification rev1_1/rev1_2, GHC.HR shall only be set to ¡®1¡¯ > by software when GHC.AE is set to ¡®1¡¯. > > Signed-off-by: Peer Chen <peerchen@gmail.com> > --- > --- linux-2.6.23-rc7/drivers/ata/ahci.c.orig 2007-09-20 11:01:55.000000000 -0400 > +++ linux-2.6.23-rc7/drivers/ata/ahci.c 2007-09-20 11:07:31.000000000 -0400 > @@ -834,6 +834,10 @@ static int ahci_reset_controller(struct > void __iomem *mmio = host->iomap[AHCI_PCI_BAR]; > u32 tmp; > > + /* turn on AHCI mode before controller reset*/ > + writel(HOST_AHCI_EN, mmio + HOST_CTL); > + (void) readl(mmio + HOST_CTL); /* flush */ > + > /* global controller reset */ > tmp = readl(mmio + HOST_CTL); > if ((tmp & HOST_RESET) == 0) {
I appreciate the readl() flushes, but in this particular case we end up reading the exact offset again below.
-- Jens Axboe
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