MIPS: Netlogic: Use PIC timer as a clocksource

The XLR/XLS/XLP PIC has a 8 countdown timers which run at the PIC
frequencey. One of these can be used as a clocksource to provide
timestamps that is common across cores. This can be used in place
of the count/compare clocksource which is per-CPU.

On XLR/XLS PIC registers are 32-bit, so we just use the lower 32-bits
of the PIC counter. On XLP, the whole 64-bit can be used.

Provide common macros and functions for PIC timer registers on XLR/XLS
and XLP, and use them to register a PIC clocksource.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Patchwork: http://patchwork.linux-mips.org/patch/4786/
Signed-off-by: John Crispin <blogic@openwrt.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/arch/mips/netlogic/common/time.c b/arch/mips/netlogic/common/time.c
index bd3e498157ff..20f89bc0507f 100644
--- a/arch/mips/netlogic/common/time.c
+++ b/arch/mips/netlogic/common/time.c
@@ -35,16 +35,68 @@
 #include <linux/init.h>
 
 #include <asm/time.h>
+#include <asm/cpu-features.h>
+
 #include <asm/netlogic/interrupt.h>
 #include <asm/netlogic/common.h>
+#include <asm/netlogic/haldefs.h>
+#include <asm/netlogic/common.h>
+
+#if defined(CONFIG_CPU_XLP)
+#include <asm/netlogic/xlp-hal/iomap.h>
+#include <asm/netlogic/xlp-hal/xlp.h>
+#include <asm/netlogic/xlp-hal/pic.h>
+#elif defined(CONFIG_CPU_XLR)
+#include <asm/netlogic/xlr/iomap.h>
+#include <asm/netlogic/xlr/pic.h>
+#include <asm/netlogic/xlr/xlr.h>
+#else
+#error "Unknown CPU"
+#endif
 
 unsigned int __cpuinit get_c0_compare_int(void)
 {
         return IRQ_TIMER;
 }
 
+static cycle_t nlm_get_pic_timer(struct clocksource *cs)
+{
+        uint64_t picbase = nlm_get_node(0)->picbase;
+
+        return ~nlm_pic_read_timer(picbase, PIC_CLOCK_TIMER);
+}
+
+static cycle_t nlm_get_pic_timer32(struct clocksource *cs)
+{
+        uint64_t picbase = nlm_get_node(0)->picbase;
+
+        return ~nlm_pic_read_timer32(picbase, PIC_CLOCK_TIMER);
+}
+
+static struct clocksource csrc_pic = {
+        .name           = "PIC",
+        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static void nlm_init_pic_timer(void)
+{
+        uint64_t picbase = nlm_get_node(0)->picbase;
+
+        nlm_pic_set_timer(picbase, PIC_CLOCK_TIMER, ~0ULL, 0, 0);
+        if (current_cpu_data.cputype == CPU_XLR) {
+                csrc_pic.mask   = CLOCKSOURCE_MASK(32);
+                csrc_pic.read   = nlm_get_pic_timer32;
+        } else {
+                csrc_pic.mask   = CLOCKSOURCE_MASK(64);
+                csrc_pic.read   = nlm_get_pic_timer;
+        }
+        csrc_pic.rating = 1000;
+        clocksource_register_hz(&csrc_pic, PIC_CLK_HZ);
+}
+
 void __init plat_time_init(void)
 {
+        nlm_init_pic_timer();
         mips_hpt_frequency = nlm_get_cpu_frequency();
         pr_info("MIPS counter frequency [%ld]\n",
                         (unsigned long)mips_hpt_frequency);