From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Date: Wed, 14 Oct 2015 18:32:42 +0200 Subject: [U-Boot] [PATCH 2/2] arm: socfpga: enable data/inst prefetch and shared override in the L2 In-Reply-To: <1444661997-23059-2-git-send-email-dinguyen@opensource.altera.com> References: <1444661997-23059-1-git-send-email-dinguyen@opensource.altera.com> <1444661997-23059-2-git-send-email-dinguyen@opensource.altera.com> Message-ID: <20151014163242.GB1954@amd> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Mon 2015-10-12 09:59:57, dinguyen at opensource.altera.com wrote: > From: Dinh Nguyen > > Update the L2 AUX CTRL settings for the SoCFPGA. > > Enabling D and I prefetch bits helps improve SDRAM performance on the > platform. > > Also, we need to enable bit 22 of the L2. By not having bit 22 set in the > PL310 Auxiliary Control register (shared attribute override enable) has the > side effect of transforming Normal Shared Non-cacheable reads into Cacheable > no-allocate reads. > > Coherent DMA buffers in Linux always have a Cacheable alias via the > kernel linear mapping and the processor can speculatively load cache > lines into the PL310 controller. With bit 22 cleared, Non-cacheable > reads would unexpectedly hit such cache lines leading to buffer > corruption. > > Signed-off-by: Dinh Nguyen > --- > arch/arm/include/asm/pl310.h | 2 ++ > arch/arm/mach-socfpga/misc.c | 12 ++++++++++++ > 2 files changed, 14 insertions(+) > > diff --git a/arch/arm/include/asm/pl310.h b/arch/arm/include/asm/pl310.h > index 18b90b7..7a11405 100644 > --- a/arch/arm/include/asm/pl310.h > +++ b/arch/arm/include/asm/pl310.h > @@ -17,6 +17,8 @@ > #define L2X0_CTRL_EN 1 > > #define PL310_SHARED_ATT_OVERRIDE_ENABLE (1 << 22) > +#define PL310_AUX_CTRL_DATA_PREFETCH_MASK (1 << 28) > +#define PL310_AUX_CTRL_INST_PREFETCH_MASK (1 << 29) These would be arch/arm/include/asm/hardware/cache-l2x0.h:#define L310_PREFETCH_CTRL_DATA_PREFETCH BIT(28) arch/arm/include/asm/hardware/cache-l2x0.h:#define L310_PREFETCH_CTRL_INSTR_PREFETCH BIT(29) ...in kernel. So maybe staying with L310_ prefix makes sense? Otherwise it looks ok. Best regards, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html