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Commit 4374d649 authored by Russell King's avatar Russell King
Browse files

ARM: l2c: add automatic enable of early BRESP 



The AXI bus protocol requires that a write response should only be
sent back to the master when the last write has been accepted.  Early
BRESP allows the L2C-310 to send the write response as soon as the
store buffer accepts the write address.

Cortex-A9 processors can signal to the L2C-310 that they wish to be
notified early, and if this optimisation is enabled, the L2C-310 can
signal an early write response.

Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent ddf7d79b

arch/arm/mm/cache-l2x0.c

+22 −3
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/of_address.h>



#include <asm/cacheflush.h>

#include <asm/cputype.h>

#include <asm/hardware/cache-l2x0.h>

#include "cache-tauros3.h"

#include "cache-aurora-l2.h"
@@ -638,6 +639,24 @@ static void l2c310_resume(void) 
	}

}



static void __init l2c310_enable(void __iomem *base, u32 aux, unsigned num_lock)

{

	unsigned rev = readl_relaxed(base + L2X0_CACHE_ID) & L2X0_CACHE_ID_PART_MASK;

	bool cortex_a9 = read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9;



	if (rev >= L310_CACHE_ID_RTL_R2P0) {

		if (cortex_a9) {

			aux |= L310_AUX_CTRL_EARLY_BRESP;

			pr_info("L2C-310 enabling early BRESP for Cortex-A9\n");

		} else if (aux & L310_AUX_CTRL_EARLY_BRESP) {

			pr_warn("L2C-310 early BRESP only supported with Cortex-A9\n");

			aux &= ~L310_AUX_CTRL_EARLY_BRESP;

		}

	}



	l2c_enable(base, aux, num_lock);

}



static void __init l2c310_fixup(void __iomem *base, u32 cache_id,

	struct outer_cache_fns *fns)

{
@@ -699,7 +718,7 @@ static const struct l2c_init_data l2c310_init_fns __initconst = { 
	.type = "L2C-310",

	.way_size_0 = SZ_8K,

	.num_lock = 8,

	.enable = l2c_enable,

	.enable = l2c310_enable,

	.fixup = l2c310_fixup,

	.save = l2c310_save,

	.outer_cache = {
@@ -940,7 +959,7 @@ static const struct l2c_init_data of_l2c310_data __initconst = { 
	.way_size_0 = SZ_8K,

	.num_lock = 8,

	.of_parse = l2c310_of_parse,

	.enable = l2c_enable,

	.enable = l2c310_enable,

	.fixup = l2c310_fixup,

	.save  = l2c310_save,

	.outer_cache = {
@@ -1289,7 +1308,7 @@ static const struct l2c_init_data of_bcm_l2x0_data __initconst = { 
	.way_size_0 = SZ_8K,

	.num_lock = 8,

	.of_parse = l2c310_of_parse,

	.enable = l2c_enable,

	.enable = l2c310_enable,

	.save  = l2c310_save,

	.outer_cache = {

		.inv_range   = bcm_inv_range,