arch/arm/mach-sunxi/dram_helpers.c

   1 /*
   2  * DRAM init helper functions
   3  *
   4  * (C) Copyright 2015 Hans de Goede <hdegoede@redhat.com>
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <asm/armv7.h>
  11 #include <asm/io.h>
  12 #include <asm/arch/dram.h>
  13
  14 /*
  15  * Wait up to 1s for value to be set in given part of reg.
  16  */
  17 void mctl_await_completion(u32 *reg, u32 mask, u32 val)
  18 {
  19         unsigned long tmo = timer_get_us() + 1000000;
  20
  21         while ((readl(reg) & mask) != val) {
  22                 if (timer_get_us() > tmo)
  23                         panic("Timeout initialising DRAM\n");
  24         }
  25 }
  26
  27 /*
  28  * Test if memory at offset offset matches memory at begin of DRAM
  29  */
  30 bool mctl_mem_matches(u32 offset)
  31 {
  32         /* Try to write different values to RAM at two addresses */
  33         writel(0, CONFIG_SYS_SDRAM_BASE);
  34         writel(0xaa55aa55, (ulong)CONFIG_SYS_SDRAM_BASE + offset);
  35         DSB;
  36         /* Check if the same value is actually observed when reading back */
  37         return readl(CONFIG_SYS_SDRAM_BASE) ==
  38                readl((ulong)CONFIG_SYS_SDRAM_BASE + offset);
  39 }