[ARM] 3206/1: Modifications to the bus arbiter controller for the Intel PXA27x

Patch from Jared Hulbert

The following patch changes the bus arbiter controller settings
for the Intel PXA27x Application Processor Family.  Up to 5%
better video performance.  It parks the bus on the core while not
in use and sets the arbitration for other bus items.  The patch
only applies changes to the Intel Mainstone development platform.

This patch is not compatible with preproduction Intel PXA27x
silicon.

This patch is based on the Intel Linux Preview Kit released to the
public on 25 Feb. 2005 found at
ftp://ftp.arm.linux.org.uk/pub/linux/arm/people/xscale/mainstone/02-25-2005/.

Signed-off-by: Justin A Treon <justin_treon@yahoo.com>
Signed-off-by: Jared Hulbert <jaredeh@gmail.com>
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 18 insertions, 0 deletions

diff --git a/arch/arm/mach-pxa/mainstone.c b/arch/arm/mach-pxa/mainstone.c
index 07892f4012d8..fe7404318aa8 100644
--- a/arch/arm/mach-pxa/mainstone.c
+++ b/arch/arm/mach-pxa/mainstone.c
@@ -407,6 +407,12 @@ static void __init mainstone_init(void)
         printk(KERN_NOTICE "Mainstone configured to boot from %s\n",
                mst_flash_data[0].name);
 
+        /* system bus arbiter setting
+         * - Core_Park
+         * - LCD_wt:DMA_wt:CORE_Wt = 2:3:4
+         */
+        ARB_CNTRL = ARB_CORE_PARK | 0x234;
+
         /*
          * On Mainstone, we route AC97_SYSCLK via GPIO45 to
          * the audio daughter card
diff --git a/include/asm-arm/arch-pxa/pxa-regs.h b/include/asm-arm/arch-pxa/pxa-regs.h
index a75a2470f4f5..dae138b9cac5 100644
--- a/include/asm-arm/arch-pxa/pxa-regs.h
+++ b/include/asm-arm/arch-pxa/pxa-regs.h
@@ -2042,6 +2042,18 @@
 
 #ifdef CONFIG_PXA27x
 
+#define ARB_CNTRL       __REG(0x48000048)  /* Arbiter Control Register */
+
+#define ARB_DMA_SLV_PARK        (1<<31)    /* Be parked with DMA slave when idle */
+#define ARB_CI_PARK             (1<<30)    /* Be parked with Camera Interface when idle */
+#define ARB_EX_MEM_PARK         (1<<29)    /* Be parked with external MEMC when idle */
+#define ARB_INT_MEM_PARK        (1<<28)    /* Be parked with internal MEMC when idle */
+#define ARB_USB_PARK            (1<<27)    /* Be parked with USB when idle */
+#define ARB_LCD_PARK            (1<<26)    /* Be parked with LCD when idle */
+#define ARB_DMA_PARK            (1<<25)    /* Be parked with DMA when idle */
+#define ARB_CORE_PARK           (1<<24)    /* Be parked with core when idle */
+#define ARB_LOCK_FLAG           (1<<23)    /* Only Locking masters gain access to the bus */
+
 /*
  * Keypad
  */