target/linux/ramips/patches-3.18/0023-MIPS-ralink-mt7620-fix-usb-issue-during-frequency-sc.patch

   1 From 1f1c12e85defba9459b41ec95b86f23b4791f1ab Mon Sep 17 00:00:00 2001
   2 From: John Crispin <blogic@openwrt.org>
   3 Date: Mon, 4 Aug 2014 20:43:25 +0200
   4 Subject: [PATCH 23/57] MIPS: ralink: mt7620: fix usb issue during frequency
   5  scaling
   6
   7  If the USB HCD is running and the cpu is scaled too low, then the USB stops
   8  working. Increase the idle speed of the core to fix this if the kernel is
   9  built with USB support.
  10
  11  The values are taken from the Ralink SDK Kernel.
  12
  13  Signed-off-by: John Crispin <blogic@openwrt.org>
  14 ---
  15  arch/mips/ralink/mt7620.c |   19 +++++++++++++++++++
  16  1 file changed, 19 insertions(+)
  17
  18 --- a/arch/mips/ralink/mt7620.c
  19 +++ b/arch/mips/ralink/mt7620.c
  20 @@ -36,6 +36,12 @@
  21  #define PMU1_CFG               0x8C
  22  #define DIG_SW_SEL             BIT(25)
  23
  24 +/* clock scaling */
  25 +#define CLKCFG_FDIV_MASK       0x1f00
  26 +#define CLKCFG_FDIV_USB_VAL    0x0300
  27 +#define CLKCFG_FFRAC_MASK      0x001f
  28 +#define CLKCFG_FFRAC_USB_VAL   0x0003
  29 +
  30  /* does the board have sdram or ddram */
  31  static int dram_type;
  32
  33 @@ -337,6 +343,19 @@ void __init ralink_clk_init(void)
  34         ralink_clk_add("10000b00.spi", sys_rate);
  35         ralink_clk_add("10000c00.uartlite", periph_rate);
  36         ralink_clk_add("10180000.wmac", xtal_rate);
  37 +
  38 +       if (IS_ENABLED(CONFIG_USB)) {
  39 +               /*
  40 +                * When the CPU goes into sleep mode, the BUS clock will be too low for
  41 +                * USB to function properly
  42 +                */
  43 +               u32 val = rt_sysc_r32(SYSC_REG_CPU_SYS_CLKCFG);
  44 +
  45 +               val &= ~(CLKCFG_FDIV_MASK | CLKCFG_FFRAC_MASK);
  46 +               val |= CLKCFG_FDIV_USB_VAL | CLKCFG_FFRAC_USB_VAL;
  47 +
  48 +               rt_sysc_w32(val, SYSC_REG_CPU_SYS_CLKCFG);
  49 +       }
  50  }
  51
  52  void __init ralink_of_remap(void)