target/linux/brcm2708/patches-4.19/950-0198-dwc-otg-FIQ-Fix-bad-mode-in-data-abort-handler.patch

   1 From f36b3119d83e03c9d0c684b8712b66a979c48124 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Mon, 16 Jul 2018 14:40:13 +0100
   4 Subject: [PATCH] dwc-otg: FIQ: Fix "bad mode in data abort handler"
   5
   6 Create a semi-static mapping for the USB registers early in the boot
   7 process, before additional kernel threads are started, so all threads
   8 will have the mappings from the start. This avoids the need for
   9 data aborts to lazily update them.
  10
  11 See: https://github.com/raspberrypi/linux/issues/2450
  12
  13 Signed-off-by: Floris Bos <bos@je-eigen-domein.nl>
  14 ---
  15  arch/arm/mach-bcm/board_bcm2835.c         | 69 +++++++++++++++++++++++
  16  drivers/usb/host/dwc_otg/dwc_otg_driver.c |  2 +-
  17  2 files changed, 70 insertions(+), 1 deletion(-)
  18
  19 --- a/arch/arm/mach-bcm/board_bcm2835.c
  20 +++ b/arch/arm/mach-bcm/board_bcm2835.c
  21 @@ -15,6 +15,7 @@
  22  #include <linux/init.h>
  23  #include <linux/irqchip.h>
  24  #include <linux/of_address.h>
  25 +#include <linux/of_fdt.h>
  26  #include <asm/system_info.h>
  27
  28  #include <asm/mach/arch.h>
  29 @@ -22,6 +23,9 @@
  30
  31  #include "platsmp.h"
  32
  33 +#define BCM2835_USB_VIRT_BASE   0xf0980000
  34 +#define BCM2835_USB_VIRT_MPHI   0xf0006000
  35 +
  36  static void __init bcm2835_init(void)
  37  {
  38         struct device_node *np = of_find_node_by_path("/system");
  39 @@ -34,6 +38,70 @@ static void __init bcm2835_init(void)
  40                 system_serial_low = val64;
  41  }
  42
  43 +/*
  44 + * We need to map registers that are going to be accessed by the FIQ
  45 + * very early, before any kernel threads are spawned. Because if done
  46 + * later, the mapping tables are not updated instantly but lazily upon
  47 + * first access through a data abort handler. While that is fine
  48 + * when executing regular kernel code, if the first access in a specific
  49 + * thread happens while running FIQ code this will result in a panic.
  50 + *
  51 + * For more background see the following old mailing list thread:
  52 + * https://www.spinics.net/lists/arm-kernel/msg325250.html
  53 + */
  54 +static int __init bcm2835_map_usb(unsigned long node, const char *uname,
  55 +                                       int depth, void *data)
  56 +{
  57 +       struct map_desc map[2];
  58 +       const __be32 *reg;
  59 +       int len;
  60 +       unsigned long p2b_offset = *((unsigned long *) data);
  61 +
  62 +       if (!of_flat_dt_is_compatible(node, "brcm,bcm2708-usb"))
  63 +               return 0;
  64 +       reg = of_get_flat_dt_prop(node, "reg", &len);
  65 +       if (!reg || len != (sizeof(unsigned long) * 4))
  66 +               return 0;
  67 +
  68 +       /* Use information about the physical addresses of the
  69 +        * registers from the device tree, but use legacy
  70 +        * iotable_init() static mapping function to map them,
  71 +        * as ioremap() is not functional at this stage in boot.
  72 +        */
  73 +       map[0].virtual = (unsigned long) BCM2835_USB_VIRT_BASE;
  74 +       map[0].pfn = __phys_to_pfn(be32_to_cpu(reg[0]) - p2b_offset);
  75 +       map[0].length = be32_to_cpu(reg[1]);
  76 +       map[0].type = MT_DEVICE;
  77 +       map[1].virtual = (unsigned long) BCM2835_USB_VIRT_MPHI;
  78 +       map[1].pfn = __phys_to_pfn(be32_to_cpu(reg[2]) - p2b_offset);
  79 +       map[1].length = be32_to_cpu(reg[3]);
  80 +       map[1].type = MT_DEVICE;
  81 +               iotable_init(map, 2);
  82 +
  83 +       return 1;
  84 +}
  85 +
  86 +static void __init bcm2835_map_io(void)
  87 +{
  88 +       const __be32 *ranges;
  89 +       int soc, len;
  90 +       unsigned long p2b_offset;
  91 +
  92 +       debug_ll_io_init();
  93 +
  94 +       /* Find out how to map bus to physical address first from soc/ranges */
  95 +       soc = of_get_flat_dt_subnode_by_name(of_get_flat_dt_root(), "soc");
  96 +       if (soc < 0)
  97 +               return;
  98 +       ranges = of_get_flat_dt_prop(soc, "ranges", &len);
  99 +       if (!ranges || len < (sizeof(unsigned long) * 3))
 100 +               return;
 101 +       p2b_offset = be32_to_cpu(ranges[0]) - be32_to_cpu(ranges[1]);
 102 +
 103 +       /* Now search for bcm2708-usb node in device tree */
 104 +       of_scan_flat_dt(bcm2835_map_usb, &p2b_offset);
 105 +}
 106 +
 107  static const char * const bcm2835_compat[] = {
 108  #ifdef CONFIG_ARCH_MULTI_V6
 109         "brcm,bcm2835",
 110 @@ -46,6 +114,7 @@ static const char * const bcm2835_compat
 111  };
 112
 113  DT_MACHINE_START(BCM2835, "BCM2835")
 114 +       .map_io = bcm2835_map_io,
 115         .init_machine = bcm2835_init,
 116         .dt_compat = bcm2835_compat,
 117         .smp = smp_ops(bcm2836_smp_ops),
 118 --- a/drivers/usb/host/dwc_otg/dwc_otg_driver.c
 119 +++ b/drivers/usb/host/dwc_otg/dwc_otg_driver.c
 120 @@ -837,7 +837,7 @@ static int dwc_otg_driver_probe(
 121                 retval = -ENOMEM;
 122                 goto fail;
 123         }
 124 -       dev_dbg(&_dev->dev, "base=0x%08x\n",
 125 +       dev_info(&_dev->dev, "base=0x%08x\n",
 126                  (unsigned)dwc_otg_device->os_dep.base);
 127  #endif
 128