From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH] ahci: retry enabling AHCI a few times before spitting out WARN_ON() Date: Wed, 23 Apr 2008 20:52:58 +0900 Message-ID: <480F231A.7020401@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from qb-out-0506.google.com ([72.14.204.230]:55969 "EHLO qb-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751642AbYDWLxJ (ORCPT ); Wed, 23 Apr 2008 07:53:09 -0400 Received: by qb-out-0506.google.com with SMTP id e11so2568686qbe.15 for ; Wed, 23 Apr 2008 04:53:08 -0700 (PDT) Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jeff Garzik , IDE/ATA development list , Peer Chen , "Hemmann, Volker Armin" 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: Tejun Heo Cc: Peer Chen Cc: Volker Armin Hemmann --- drivers/ata/ahci.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c index 739ba3f..711b5d7 100644 --- a/drivers/ata/ahci.c +++ b/drivers/ata/ahci.c @@ -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); } /**