openwrt/target/linux/bcm53xx/patches-4.1/075-ARM-8391-1-l2c-add-options-to-overwrite-prefetching-.patch

From ec3bd0e68a679a7af2c46af1ddc9af8b534a8b0e Mon Sep 17 00:00:00 2001
From: Hauke Mehrtens <hauke@hauke-m.de>
Date: Wed, 10 Jun 2015 20:23:24 +0100
Subject: [PATCH] ARM: 8391/1: l2c: add options to overwrite prefetching
 behavior

These options make it possible to overwrites the data and instruction
prefetching behavior of the arm pl310 cache controller.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 Documentation/devicetree/bindings/arm/l2cc.txt |  5 +++++
 arch/arm/mm/cache-l2x0.c                       | 20 ++++++++++++++++++++
 2 files changed, 25 insertions(+)

--- a/Documentation/devicetree/bindings/arm/l2cc.txt
+++ b/Documentation/devicetree/bindings/arm/l2cc.txt
@@ -67,6 +67,11 @@ Optional properties:
   disable if zero.
 - arm,prefetch-offset : Override prefetch offset value. Valid values are
   0-7, 15, 23, and 31.
+- prefetch-data : Data prefetch. Value: <0> (forcibly disable), <1>
+  (forcibly enable), property absent (retain settings set by firmware)
+- prefetch-instr : Instruction prefetch. Value: <0> (forcibly disable),
+  <1> (forcibly enable), property absent (retain settings set by
+  firmware)
 
 Example:
 
--- a/arch/arm/mm/cache-l2x0.c
+++ b/arch/arm/mm/cache-l2x0.c
@@ -1221,6 +1221,26 @@ static void __init l2c310_of_parse(const
 		pr_err("L2C-310 OF arm,prefetch-offset property value is missing\n");
 	}
 
+	ret = of_property_read_u32(np, "prefetch-data", &val);
+	if (ret == 0) {
+		if (val)
+			prefetch |= L310_PREFETCH_CTRL_DATA_PREFETCH;
+		else
+			prefetch &= ~L310_PREFETCH_CTRL_DATA_PREFETCH;
+	} else if (ret != -EINVAL) {
+		pr_err("L2C-310 OF prefetch-data property value is missing\n");
+	}
+
+	ret = of_property_read_u32(np, "prefetch-instr", &val);
+	if (ret == 0) {
+		if (val)
+			prefetch |= L310_PREFETCH_CTRL_INSTR_PREFETCH;
+		else
+			prefetch &= ~L310_PREFETCH_CTRL_INSTR_PREFETCH;
+	} else if (ret != -EINVAL) {
+		pr_err("L2C-310 OF prefetch-instr property value is missing\n");
+	}
+
 	l2x0_saved_regs.prefetch_ctrl = prefetch;
 }