ARM: shmobile: rcar-gen2: Add CA7 arch_timer initialization for r8a7794

On E2, the arch timer is hooked up to a different clock, and the CA7's arch
timer CNTVOFF register must be initialized.

Based on work by Hisashi Nakamura.

Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

1 files changed, 49 insertions, 23 deletions

diff --git a/arch/arm/mach-shmobile/setup-rcar-gen2.c b/arch/arm/mach-shmobile/setup-rcar-gen2.c
index 42d5b4308923..7ed92790d13f 100644
--- a/arch/arm/mach-shmobile/setup-rcar-gen2.c
+++ b/arch/arm/mach-shmobile/setup-rcar-gen2.c
@@ -3,6 +3,7 @@
  *
  * Copyright (C) 2013  Renesas Solutions Corp.
  * Copyright (C) 2013  Magnus Damm
+ * Copyright (C) 2014  Ulrich Hecht
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -24,6 +25,7 @@
 #include <linux/dma-contiguous.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
+#include <linux/of.h>
 #include <linux/of_fdt.h>
 #include <asm/mach/arch.h>
 #include "common.h"
@@ -54,37 +56,61 @@ void __init rcar_gen2_timer_init(void)
 {
 #if defined(CONFIG_ARM_ARCH_TIMER) || defined(CONFIG_COMMON_CLK)
         u32 mode = rcar_gen2_read_mode_pins();
+        bool is_e2 = (bool)of_find_compatible_node(NULL, NULL,
+                "renesas,r8a7794");
 #endif
 #ifdef CONFIG_ARM_ARCH_TIMER
         void __iomem *base;
         int extal_mhz = 0;
         u32 freq;
 
-        /* At Linux boot time the r8a7790 arch timer comes up
-         * with the counter disabled. Moreover, it may also report
-         * a potentially incorrect fixed 13 MHz frequency. To be
-         * correct these registers need to be updated to use the
-         * frequency EXTAL / 2 which can be determined by the MD pins.
-         */
-
-        switch (mode & (MD(14) | MD(13))) {
-        case 0:
-                extal_mhz = 15;
-                break;
-        case MD(13):
-                extal_mhz = 20;
-                break;
-        case MD(14):
-                extal_mhz = 26;
-                break;
-        case MD(13) | MD(14):
-                extal_mhz = 30;
-                break;
+        if (is_e2) {
+                freq = 260000000 / 8;   /* ZS / 8 */
+                /* CNTVOFF has to be initialized either from non-secure
+                 * Hypervisor mode or secure Monitor mode with SCR.NS==1.
+                 * If TrustZone is enabled then it should be handled by the
+                 * secure code.
+                 */
+                asm volatile(
+                "       cps     0x16\n"
+                "       mrc     p15, 0, r1, c1, c1, 0\n"
+                "       orr     r0, r1, #1\n"
+                "       mcr     p15, 0, r0, c1, c1, 0\n"
+                "       isb\n"
+                "       mov     r0, #0\n"
+                "       mcrr    p15, 4, r0, r0, c14\n"
+                "       isb\n"
+                "       mcr     p15, 0, r1, c1, c1, 0\n"
+                "       isb\n"
+                "       cps     0x13\n"
+                        : : : "r0", "r1");
+        } else {
+                /* At Linux boot time the r8a7790 arch timer comes up
+                 * with the counter disabled. Moreover, it may also report
+                 * a potentially incorrect fixed 13 MHz frequency. To be
+                 * correct these registers need to be updated to use the
+                 * frequency EXTAL / 2 which can be determined by the MD pins.
+                 */
+
+                switch (mode & (MD(14) | MD(13))) {
+                case 0:
+                        extal_mhz = 15;
+                        break;
+                case MD(13):
+                        extal_mhz = 20;
+                        break;
+                case MD(14):
+                        extal_mhz = 26;
+                        break;
+                case MD(13) | MD(14):
+                        extal_mhz = 30;
+                        break;
+                }
+
+                /* The arch timer frequency equals EXTAL / 2 */
+                freq = extal_mhz * (1000000 / 2);
         }
 
-        /* The arch timer frequency equals EXTAL / 2 */
-        freq = extal_mhz * (1000000 / 2);
-
         /* Remap "armgcnt address map" space */
         base = ioremap(0xe6080000, PAGE_SIZE);