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

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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>
This commit is contained in:
Huacai Chen 2014-11-04 14:15:31 +08:00 committed by Ralf Baechle
parent 89467e73d3
commit e292ccde21
6 changed files with 350 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

73
arch/mips/include/asm/hpet.h Normal file
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@ -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 */

12
arch/mips/loongson/Kconfig
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@ -108,6 +108,18 @@ config CS5536_MFGPT
If unsure, say Yes.
config RS780_HPET
bool "RS780/SBX00 HPET Timer"
depends on LOONGSON_MACH3X
select MIPS_EXTERNAL_TIMER
help
This option enables the hpet timer of AMD RS780/SBX00.
If you want to enable the Loongson3 CPUFreq Driver, Please enable
this option at first, otherwise, You will get wrong system time.
If unsure, say Yes.
config LOONGSON_SUSPEND
bool
default y

5
arch/mips/loongson/common/time.c
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@ -12,6 +12,7 @@
*/
#include <asm/mc146818-time.h>
#include <asm/time.h>
#include <asm/hpet.h>
#include <loongson.h>
#include <cs5536/cs5536_mfgpt.h>
@ -21,7 +22,11 @@ void __init plat_time_init(void)
/* setup mips r4k timer */
mips_hpt_frequency = cpu_clock_freq / 2;
#ifdef CONFIG_RS780_HPET
setup_hpet_timer();
#else
setup_mfgpt0_timer();
#endif
}
void read_persistent_clock(struct timespec *ts)

2
arch/mips/loongson/loongson-3/Makefile
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@ -6,3 +6,5 @@ obj-y += irq.o cop2-ex.o platform.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_NUMA) += numa.o
obj-$(CONFIG_RS780_HPET) += hpet.o

257
arch/mips/loongson/loongson-3/hpet.c Normal file
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@ -0,0 +1,257 @@
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/percpu.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <asm/hpet.h>
#include <asm/time.h>
#define SMBUS_CFG_BASE (loongson_sysconf.ht_control_base + 0x0300a000)
#define SMBUS_PCI_REG40 0x40
#define SMBUS_PCI_REG64 0x64
#define SMBUS_PCI_REGB4 0xb4
static DEFINE_SPINLOCK(hpet_lock);
DEFINE_PER_CPU(struct clock_event_device, hpet_clockevent_device);
static unsigned int smbus_read(int offset)
{
return *(volatile unsigned int *)(SMBUS_CFG_BASE + offset);
}
static void smbus_write(int offset, int data)
{
*(volatile unsigned int *)(SMBUS_CFG_BASE + offset) = data;
}
static void smbus_enable(int offset, int bit)
{
unsigned int cfg = smbus_read(offset);
cfg |= bit;
smbus_write(offset, cfg);
}
static int hpet_read(int offset)
{
return *(volatile unsigned int *)(HPET_MMIO_ADDR + offset);
}
static void hpet_write(int offset, int data)
{
*(volatile unsigned int *)(HPET_MMIO_ADDR + offset) = data;
}
static void hpet_start_counter(void)
{
unsigned int cfg = hpet_read(HPET_CFG);
cfg |= HPET_CFG_ENABLE;
hpet_write(HPET_CFG, cfg);
}
static void hpet_stop_counter(void)
{
unsigned int cfg = hpet_read(HPET_CFG);
cfg &= ~HPET_CFG_ENABLE;
hpet_write(HPET_CFG, cfg);
}
static void hpet_reset_counter(void)
{
hpet_write(HPET_COUNTER, 0);
hpet_write(HPET_COUNTER + 4, 0);
}
static void hpet_restart_counter(void)
{
hpet_stop_counter();
hpet_reset_counter();
hpet_start_counter();
}
static void hpet_enable_legacy_int(void)
{
/* Do nothing on Loongson-3 */
}
static void hpet_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
int cfg = 0;
spin_lock(&hpet_lock);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
pr_info("set clock event to periodic mode!\n");
/* stop counter */
hpet_stop_counter();
/* enables the timer0 to generate a periodic interrupt */
cfg = hpet_read(HPET_T0_CFG);
cfg &= ~HPET_TN_LEVEL;
cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC |
HPET_TN_SETVAL | HPET_TN_32BIT;
hpet_write(HPET_T0_CFG, cfg);
/* set the comparator */
hpet_write(HPET_T0_CMP, HPET_COMPARE_VAL);
udelay(1);
hpet_write(HPET_T0_CMP, HPET_COMPARE_VAL);
/* start counter */
hpet_start_counter();
break;
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_UNUSED:
cfg = hpet_read(HPET_T0_CFG);
cfg &= ~HPET_TN_ENABLE;
hpet_write(HPET_T0_CFG, cfg);
break;
case CLOCK_EVT_MODE_ONESHOT:
pr_info("set clock event to one shot mode!\n");
cfg = hpet_read(HPET_T0_CFG);
/* set timer0 type
* 1 : periodic interrupt
* 0 : non-periodic(oneshot) interrupt
*/
cfg &= ~HPET_TN_PERIODIC;
cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
hpet_write(HPET_T0_CFG, cfg);
break;
case CLOCK_EVT_MODE_RESUME:
hpet_enable_legacy_int();
break;
}
spin_unlock(&hpet_lock);
}
static int hpet_next_event(unsigned long delta,
struct clock_event_device *evt)
{
unsigned int cnt;
int res;
cnt = hpet_read(HPET_COUNTER);
cnt += delta;
hpet_write(HPET_T0_CMP, cnt);
res = ((int)(hpet_read(HPET_COUNTER) - cnt) > 0) ? -ETIME : 0;
return res;
}
static irqreturn_t hpet_irq_handler(int irq, void *data)
{
int is_irq;
struct clock_event_device *cd;
unsigned int cpu = smp_processor_id();
is_irq = hpet_read(HPET_STATUS);
if (is_irq & HPET_T0_IRS) {
/* clear the TIMER0 irq status register */
hpet_write(HPET_STATUS, HPET_T0_IRS);
cd = &per_cpu(hpet_clockevent_device, cpu);
cd->event_handler(cd);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
static struct irqaction hpet_irq = {
.handler = hpet_irq_handler,
.flags = IRQF_DISABLED | IRQF_NOBALANCING | IRQF_TIMER,
.name = "hpet",
};
/*
* hpet address assignation and irq setting should be done in bios.
* but pmon don't do this, we just setup here directly.
* The operation under is normal. unfortunately, hpet_setup process
* is before pci initialize.
*
* {
* struct pci_dev *pdev;
*
* pdev = pci_get_device(PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_SBX00_SMBUS, NULL);
* pci_write_config_word(pdev, SMBUS_PCI_REGB4, HPET_ADDR);
*
* ...
* }
*/
static void hpet_setup(void)
{
/* set hpet base address */
smbus_write(SMBUS_PCI_REGB4, HPET_ADDR);
/* enable decodeing of access to HPET MMIO*/
smbus_enable(SMBUS_PCI_REG40, (1 << 28));
/* HPET irq enable */
smbus_enable(SMBUS_PCI_REG64, (1 << 10));
hpet_enable_legacy_int();
}
void __init setup_hpet_timer(void)
{
unsigned int cpu = smp_processor_id();
struct clock_event_device *cd;
hpet_setup();
cd = &per_cpu(hpet_clockevent_device, cpu);
cd->name = "hpet";
cd->rating = 320;
cd->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
cd->set_mode = hpet_set_mode;
cd->set_next_event = hpet_next_event;
cd->irq = HPET_T0_IRQ;
cd->cpumask = cpumask_of(cpu);
clockevent_set_clock(cd, HPET_FREQ);
cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
cd->min_delta_ns = 5000;
clockevents_register_device(cd);
setup_irq(HPET_T0_IRQ, &hpet_irq);
pr_info("hpet clock event device register\n");
}
static cycle_t hpet_read_counter(struct clocksource *cs)
{
return (cycle_t)hpet_read(HPET_COUNTER);
}
static void hpet_suspend(struct clocksource *cs)
{
}
static void hpet_resume(struct clocksource *cs)
{
hpet_setup();
hpet_restart_counter();
}
static struct clocksource csrc_hpet = {
.name = "hpet",
/* mips clocksource rating is less than 300, so hpet is better. */
.rating = 300,
.read = hpet_read_counter,
.mask = CLOCKSOURCE_MASK(32),
/* oneshot mode work normal with this flag */
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.suspend = hpet_suspend,
.resume = hpet_resume,
.mult = 0,
.shift = 10,
};
int __init init_hpet_clocksource(void)
{
csrc_hpet.mult = clocksource_hz2mult(HPET_FREQ, csrc_hpet.shift);
return clocksource_register_hz(&csrc_hpet, HPET_FREQ);
}
arch_initcall(init_hpet_clocksource);

2
arch/mips/loongson/loongson-3/irq.c
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@ -9,7 +9,7 @@
#include "smp.h"
unsigned int ht_irq[] = {1, 3, 4, 5, 6, 7, 8, 12, 14, 15};
unsigned int ht_irq[] = {0, 1, 3, 4, 5, 6, 7, 8, 12, 14, 15};
static void ht_irqdispatch(void)
{