MIPS: Loongson-3: Add RS780/SBX00 HPET support

CPUFreq driver need external timer, so add hpet at first.

In Loongson 3, only Core-0 can receive external interrupt. As a result,
timekeeping cannot absolutely use HPET timer. We use a hybrid solution:
Core-0 use HPET as its clock event device, but other cores still use
MIPS; clock source is global and doesn't need interrupt, so use HPET.

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: Hongliang Tao <taohl@lemote.com>
Cc: John Crispin <john@phrozen.org>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/8329/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 73 insertions, 0 deletions

diff --git a/arch/mips/include/asm/hpet.h b/arch/mips/include/asm/hpet.h
new file mode 100644
index 0000000..18a8f77
--- /dev/null
+++ b/arch/mips/include/asm/hpet.h
@@ -0,0 +1,73 @@
+#ifndef _ASM_HPET_H
+#define _ASM_HPET_H
+
+#ifdef CONFIG_RS780_HPET
+
+#define HPET_MMAP_SIZE		1024
+
+#define HPET_ID			0x000
+#define HPET_PERIOD		0x004
+#define HPET_CFG		0x010
+#define HPET_STATUS		0x020
+#define HPET_COUNTER	0x0f0
+
+#define HPET_Tn_CFG(n)		(0x100 + 0x20 * n)
+#define HPET_Tn_CMP(n)		(0x108 + 0x20 * n)
+#define HPET_Tn_ROUTE(n)	(0x110 + 0x20 * n)
+
+#define HPET_T0_IRS		0x001
+#define HPET_T1_IRS		0x002
+#define HPET_T3_IRS		0x004
+
+#define HPET_T0_CFG		0x100
+#define HPET_T0_CMP		0x108
+#define HPET_T0_ROUTE	0x110
+#define HPET_T1_CFG		0x120
+#define HPET_T1_CMP		0x128
+#define HPET_T1_ROUTE	0x130
+#define HPET_T2_CFG		0x140
+#define HPET_T2_CMP		0x148
+#define HPET_T2_ROUTE	0x150
+
+#define HPET_ID_REV			0x000000ff
+#define HPET_ID_NUMBER		0x00001f00
+#define HPET_ID_64BIT		0x00002000
+#define HPET_ID_LEGSUP		0x00008000
+#define HPET_ID_VENDOR		0xffff0000
+#define HPET_ID_NUMBER_SHIFT	8
+#define HPET_ID_VENDOR_SHIFT	16
+
+#define HPET_CFG_ENABLE		0x001
+#define HPET_CFG_LEGACY		0x002
+#define HPET_LEGACY_8254		2
+#define HPET_LEGACY_RTC		8
+
+#define HPET_TN_LEVEL		0x0002
+#define HPET_TN_ENABLE		0x0004
+#define HPET_TN_PERIODIC	0x0008
+#define HPET_TN_PERIODIC_CAP	0x0010
+#define HPET_TN_64BIT_CAP	0x0020
+#define HPET_TN_SETVAL		0x0040
+#define HPET_TN_32BIT		0x0100
+#define HPET_TN_ROUTE		0x3e00
+#define HPET_TN_FSB			0x4000
+#define HPET_TN_FSB_CAP		0x8000
+#define HPET_TN_ROUTE_SHIFT	9
+
+/* Max HPET Period is 10^8 femto sec as in HPET spec */
+#define HPET_MAX_PERIOD		100000000UL
+/*
+ * Min HPET period is 10^5 femto sec just for safety. If it is less than this,
+ * then 32 bit HPET counter wrapsaround in less than 0.5 sec.
+ */
+#define HPET_MIN_PERIOD		100000UL
+
+#define HPET_ADDR		0x20000
+#define HPET_MMIO_ADDR	0x90000e0000020000
+#define HPET_FREQ		14318780
+#define HPET_COMPARE_VAL	((HPET_FREQ + HZ / 2) / HZ)
+#define HPET_T0_IRQ		0
+
+extern void __init setup_hpet_timer(void);
+#endif /* CONFIG_RS780_HPET */
+#endif /* _ASM_HPET_H */