Eric Lee / smarc-fsl-linux-kernel

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Commit c9b4470e2d9d611181fe488fdf463948d8b24901

Authored by Lennert Buytenhek
Committed by Russell King
1 parent 36ddf5bbde

[ARM] 3414/1: ep93xx: reset ethernet controller before uncompressing 

Patch from Lennert Buytenhek

The Redboot version that cirrus supplies for the cirrus ep93xx doesn't
turn off DMA from the ethernet MAC before jumping to linux, which means
that we might end up with bits of RX status and packet data scribbled
over the uncompressed kernel image.

Work around this by resetting the ethernet MAC before we uncompress.

We don't usually work around bootloader bugs, but considering that the
large majority of ep93xx boards out there have this problem, I figured
this it was justified in this case.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

Showing 1 changed file with 39 additions and 1 deletions Side-by-side Diff

include/asm-arm/arch-ep93xx/uncompress.h
Diff comments   View file @ c9b4470
... ... @@ -16,12 +16,22 @@
16 16 return *((volatile unsigned char *)ptr);
17 17 }
18 18  
  19 +static unsigned int __raw_readl(unsigned int ptr)
  20 +{
  21 + return *((volatile unsigned int *)ptr);
  22 +}
  23 +
19 24 static void __raw_writeb(unsigned char value, unsigned int ptr)
20 25 {
21 26 *((volatile unsigned char *)ptr) = value;
22 27 }
23 28  
  29 +static void __raw_writel(unsigned int value, unsigned int ptr)
  30 +{
  31 + *((volatile unsigned int *)ptr) = value;
  32 +}
24 33  
  34 +
25 35 #define PHYS_UART1_DATA 0x808c0000
26 36 #define PHYS_UART1_FLAG 0x808c0018
27 37 #define UART1_FLAG_TXFF 0x20
... ... @@ -49,6 +59,34 @@
49 59 }
50 60 }
51 61  
52   -#define arch_decomp_setup()
  62 +
  63 +/*
  64 + * Some bootloaders don't turn off DMA from the ethernet MAC before
  65 + * jumping to linux, which means that we might end up with bits of RX
  66 + * status and packet data scribbled over the uncompressed kernel image.
  67 + * Work around this by resetting the ethernet MAC before we uncompress.
  68 + */
  69 +#define PHYS_ETH_SELF_CTL 0x80010020
  70 +#define ETH_SELF_CTL_RESET 0x00000001
  71 +
  72 +static void ethernet_reset(void)
  73 +{
  74 + unsigned int v;
  75 +
  76 + /* Reset the ethernet MAC. */
  77 + v = __raw_readl(PHYS_ETH_SELF_CTL);
  78 + __raw_writel(v | ETH_SELF_CTL_RESET, PHYS_ETH_SELF_CTL);
  79 +
  80 + /* Wait for reset to finish. */
  81 + while (__raw_readl(PHYS_ETH_SELF_CTL) & ETH_SELF_CTL_RESET)
  82 + ;
  83 +}
  84 +
  85 +
  86 +static void arch_decomp_setup(void)
  87 +{
  88 + ethernet_reset();
  89 +}
  90 +
53 91 #define arch_decomp_wdog()