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

   1 From ec3bd0e68a679a7af2c46af1ddc9af8b534a8b0e Mon Sep 17 00:00:00 2001
   2 From: Hauke Mehrtens <hauke@hauke-m.de>
   3 Date: Wed, 10 Jun 2015 20:23:24 +0100
   4 Subject: [PATCH] ARM: 8391/1: l2c: add options to overwrite prefetching
   5  behavior
   6
   7 These options make it possible to overwrites the data and instruction
   8 prefetching behavior of the arm pl310 cache controller.
   9
  10 Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
  11 Acked-by: Florian Fainelli <f.fainelli@gmail.com>
  12 Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
  13 ---
  14  Documentation/devicetree/bindings/arm/l2cc.txt |  5 +++++
  15  arch/arm/mm/cache-l2x0.c                       | 20 ++++++++++++++++++++
  16  2 files changed, 25 insertions(+)
  17
  18 --- a/Documentation/devicetree/bindings/arm/l2cc.txt
  19 +++ b/Documentation/devicetree/bindings/arm/l2cc.txt
  20 @@ -67,6 +67,11 @@ Optional properties:
  21    disable if zero.
  22  - arm,prefetch-offset : Override prefetch offset value. Valid values are
  23    0-7, 15, 23, and 31.
  24 +- prefetch-data : Data prefetch. Value: <0> (forcibly disable), <1>
  25 +  (forcibly enable), property absent (retain settings set by firmware)
  26 +- prefetch-instr : Instruction prefetch. Value: <0> (forcibly disable),
  27 +  <1> (forcibly enable), property absent (retain settings set by
  28 +  firmware)
  29
  30  Example:
  31
  32 --- a/arch/arm/mm/cache-l2x0.c
  33 +++ b/arch/arm/mm/cache-l2x0.c
  34 @@ -1221,6 +1221,26 @@ static void __init l2c310_of_parse(const
  35                 pr_err("L2C-310 OF arm,prefetch-offset property value is missing\n");
  36         }
  37
  38 +       ret = of_property_read_u32(np, "prefetch-data", &val);
  39 +       if (ret == 0) {
  40 +               if (val)
  41 +                       prefetch |= L310_PREFETCH_CTRL_DATA_PREFETCH;
  42 +               else
  43 +                       prefetch &= ~L310_PREFETCH_CTRL_DATA_PREFETCH;
  44 +       } else if (ret != -EINVAL) {
  45 +               pr_err("L2C-310 OF prefetch-data property value is missing\n");
  46 +       }
  47 +
  48 +       ret = of_property_read_u32(np, "prefetch-instr", &val);
  49 +       if (ret == 0) {
  50 +               if (val)
  51 +                       prefetch |= L310_PREFETCH_CTRL_INSTR_PREFETCH;
  52 +               else
  53 +                       prefetch &= ~L310_PREFETCH_CTRL_INSTR_PREFETCH;
  54 +       } else if (ret != -EINVAL) {
  55 +               pr_err("L2C-310 OF prefetch-instr property value is missing\n");
  56 +       }
  57 +
  58         l2x0_saved_regs.prefetch_ctrl = prefetch;
  59  }
  60