From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@arm.linux.org.uk (Russell King - ARM Linux) Date: Sun, 21 Feb 2010 21:07:40 +0000 Subject: [PATCH 3/7] ARM: U300: set f_max to 24 MHz for MMCI In-Reply-To: <1266537931-12560-1-git-send-email-linus.walleij@stericsson.com> References: <1266537931-12560-1-git-send-email-linus.walleij@stericsson.com> Message-ID: <20100221210740.GA3528@n2100.arm.linux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Feb 19, 2010 at 01:05:31AM +0100, Linus Walleij wrote: > This employs the frequency setting mechanism introduced to the > MMCI to specify that this system can actually be clocked at 24 MHz. > > Signed-off-by: Linus Walleij > --- > arch/arm/mach-u300/mmc.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/arch/arm/mach-u300/mmc.c b/arch/arm/mach-u300/mmc.c > index 109f5a6..c1cb977 100644 > --- a/arch/arm/mach-u300/mmc.c > +++ b/arch/arm/mach-u300/mmc.c > @@ -101,6 +101,7 @@ int __devinit mmc_init(struct amba_device *adev) > * we have a regulator we can control instead. > */ > /* Nominally 2.85V on our platform */ > + mmci_card->mmc0_plat_data.f_max = 24000000; I bet setting this without DMA support leads to overruns/underruns on the interface. That's why MMCI has a low default - to ensure that PIO mode can keep up with the data transfers; the low maximum isn't because of something to do with ARM platforms.