/*
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* SGI RTC clock/timer routines.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Copyright (c) 2009-2013 Silicon Graphics, Inc. All Rights Reserved.
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* Copyright (c) Dimitri Sivanich
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*/
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#include <linux/clockchips.h>
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#include <linux/slab.h>
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#include <asm/uv/uv_mmrs.h>
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#include <asm/uv/uv_hub.h>
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#include <asm/uv/bios.h>
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#include <asm/uv/uv.h>
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#include <asm/apic.h>
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#include <asm/cpu.h>
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#define RTC_NAME "sgi_rtc"
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static u64 uv_read_rtc(struct clocksource *cs);
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static int uv_rtc_next_event(unsigned long, struct clock_event_device *);
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static int uv_rtc_shutdown(struct clock_event_device *evt);
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static struct clocksource clocksource_uv = {
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.name = RTC_NAME,
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.rating = 299,
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.read = uv_read_rtc,
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.mask = (u64)UVH_RTC_REAL_TIME_CLOCK_MASK,
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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static struct clock_event_device clock_event_device_uv = {
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.name = RTC_NAME,
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.features = CLOCK_EVT_FEAT_ONESHOT,
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.shift = 20,
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.rating = 400,
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.irq = -1,
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.set_next_event = uv_rtc_next_event,
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.set_state_shutdown = uv_rtc_shutdown,
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.event_handler = NULL,
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};
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static DEFINE_PER_CPU(struct clock_event_device, cpu_ced);
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/* There is one of these allocated per node */
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struct uv_rtc_timer_head {
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spinlock_t lock;
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/* next cpu waiting for timer, local node relative: */
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int next_cpu;
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/* number of cpus on this node: */
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int ncpus;
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struct {
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int lcpu; /* systemwide logical cpu number */
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u64 expires; /* next timer expiration for this cpu */
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} cpu[1];
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};
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/*
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* Access to uv_rtc_timer_head via blade id.
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*/
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static struct uv_rtc_timer_head **blade_info __read_mostly;
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static int uv_rtc_evt_enable;
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/*
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* Hardware interface routines
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*/
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/* Send IPIs to another node */
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static void uv_rtc_send_IPI(int cpu)
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{
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unsigned long apicid, val;
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int pnode;
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apicid = cpu_physical_id(cpu);
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pnode = uv_apicid_to_pnode(apicid);
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apicid |= uv_apicid_hibits;
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val = (1UL << UVH_IPI_INT_SEND_SHFT) |
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(apicid << UVH_IPI_INT_APIC_ID_SHFT) |
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(X86_PLATFORM_IPI_VECTOR << UVH_IPI_INT_VECTOR_SHFT);
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uv_write_global_mmr64(pnode, UVH_IPI_INT, val);
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}
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/* Check for an RTC interrupt pending */
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static int uv_intr_pending(int pnode)
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{
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if (is_uv1_hub())
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return uv_read_global_mmr64(pnode, UVH_EVENT_OCCURRED0) &
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UV1H_EVENT_OCCURRED0_RTC1_MASK;
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else if (is_uvx_hub())
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return uv_read_global_mmr64(pnode, UVXH_EVENT_OCCURRED2) &
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UVXH_EVENT_OCCURRED2_RTC_1_MASK;
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return 0;
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}
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/* Setup interrupt and return non-zero if early expiration occurred. */
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static int uv_setup_intr(int cpu, u64 expires)
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{
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u64 val;
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unsigned long apicid = cpu_physical_id(cpu) | uv_apicid_hibits;
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int pnode = uv_cpu_to_pnode(cpu);
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uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG,
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UVH_RTC1_INT_CONFIG_M_MASK);
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uv_write_global_mmr64(pnode, UVH_INT_CMPB, -1L);
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if (is_uv1_hub())
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uv_write_global_mmr64(pnode, UVH_EVENT_OCCURRED0_ALIAS,
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UV1H_EVENT_OCCURRED0_RTC1_MASK);
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else
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uv_write_global_mmr64(pnode, UVXH_EVENT_OCCURRED2_ALIAS,
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UVXH_EVENT_OCCURRED2_RTC_1_MASK);
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val = (X86_PLATFORM_IPI_VECTOR << UVH_RTC1_INT_CONFIG_VECTOR_SHFT) |
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((u64)apicid << UVH_RTC1_INT_CONFIG_APIC_ID_SHFT);
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/* Set configuration */
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uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG, val);
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/* Initialize comparator value */
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uv_write_global_mmr64(pnode, UVH_INT_CMPB, expires);
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if (uv_read_rtc(NULL) <= expires)
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return 0;
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return !uv_intr_pending(pnode);
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}
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/*
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* Per-cpu timer tracking routines
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*/
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static __init void uv_rtc_deallocate_timers(void)
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{
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int bid;
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for_each_possible_blade(bid) {
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kfree(blade_info[bid]);
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}
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kfree(blade_info);
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}
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/* Allocate per-node list of cpu timer expiration times. */
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static __init int uv_rtc_allocate_timers(void)
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{
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int cpu;
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blade_info = kcalloc(uv_possible_blades, sizeof(void *), GFP_KERNEL);
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if (!blade_info)
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return -ENOMEM;
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for_each_present_cpu(cpu) {
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int nid = cpu_to_node(cpu);
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int bid = uv_cpu_to_blade_id(cpu);
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int bcpu = uv_cpu_blade_processor_id(cpu);
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struct uv_rtc_timer_head *head = blade_info[bid];
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if (!head) {
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head = kmalloc_node(sizeof(struct uv_rtc_timer_head) +
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(uv_blade_nr_possible_cpus(bid) *
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2 * sizeof(u64)),
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GFP_KERNEL, nid);
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if (!head) {
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uv_rtc_deallocate_timers();
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return -ENOMEM;
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}
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spin_lock_init(&head->lock);
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head->ncpus = uv_blade_nr_possible_cpus(bid);
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head->next_cpu = -1;
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blade_info[bid] = head;
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}
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head->cpu[bcpu].lcpu = cpu;
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head->cpu[bcpu].expires = ULLONG_MAX;
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}
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return 0;
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}
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/* Find and set the next expiring timer. */
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static void uv_rtc_find_next_timer(struct uv_rtc_timer_head *head, int pnode)
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{
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u64 lowest = ULLONG_MAX;
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int c, bcpu = -1;
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head->next_cpu = -1;
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for (c = 0; c < head->ncpus; c++) {
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u64 exp = head->cpu[c].expires;
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if (exp < lowest) {
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bcpu = c;
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lowest = exp;
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}
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}
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if (bcpu >= 0) {
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head->next_cpu = bcpu;
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c = head->cpu[bcpu].lcpu;
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if (uv_setup_intr(c, lowest))
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/* If we didn't set it up in time, trigger */
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uv_rtc_send_IPI(c);
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} else {
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uv_write_global_mmr64(pnode, UVH_RTC1_INT_CONFIG,
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UVH_RTC1_INT_CONFIG_M_MASK);
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}
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}
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/*
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* Set expiration time for current cpu.
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*
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* Returns 1 if we missed the expiration time.
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*/
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static int uv_rtc_set_timer(int cpu, u64 expires)
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{
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int pnode = uv_cpu_to_pnode(cpu);
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int bid = uv_cpu_to_blade_id(cpu);
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struct uv_rtc_timer_head *head = blade_info[bid];
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int bcpu = uv_cpu_blade_processor_id(cpu);
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u64 *t = &head->cpu[bcpu].expires;
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unsigned long flags;
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int next_cpu;
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spin_lock_irqsave(&head->lock, flags);
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next_cpu = head->next_cpu;
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*t = expires;
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/* Will this one be next to go off? */
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if (next_cpu < 0 || bcpu == next_cpu ||
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expires < head->cpu[next_cpu].expires) {
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head->next_cpu = bcpu;
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if (uv_setup_intr(cpu, expires)) {
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*t = ULLONG_MAX;
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uv_rtc_find_next_timer(head, pnode);
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spin_unlock_irqrestore(&head->lock, flags);
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return -ETIME;
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}
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}
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spin_unlock_irqrestore(&head->lock, flags);
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return 0;
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}
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/*
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* Unset expiration time for current cpu.
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*
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* Returns 1 if this timer was pending.
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*/
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static int uv_rtc_unset_timer(int cpu, int force)
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{
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int pnode = uv_cpu_to_pnode(cpu);
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int bid = uv_cpu_to_blade_id(cpu);
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struct uv_rtc_timer_head *head = blade_info[bid];
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int bcpu = uv_cpu_blade_processor_id(cpu);
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u64 *t = &head->cpu[bcpu].expires;
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unsigned long flags;
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int rc = 0;
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spin_lock_irqsave(&head->lock, flags);
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if ((head->next_cpu == bcpu && uv_read_rtc(NULL) >= *t) || force)
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rc = 1;
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if (rc) {
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*t = ULLONG_MAX;
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/* Was the hardware setup for this timer? */
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if (head->next_cpu == bcpu)
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uv_rtc_find_next_timer(head, pnode);
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}
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spin_unlock_irqrestore(&head->lock, flags);
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return rc;
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}
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/*
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* Kernel interface routines.
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*/
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/*
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* Read the RTC.
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*
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* Starting with HUB rev 2.0, the UV RTC register is replicated across all
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* cachelines of it's own page. This allows faster simultaneous reads
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* from a given socket.
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*/
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static u64 uv_read_rtc(struct clocksource *cs)
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{
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unsigned long offset;
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if (uv_get_min_hub_revision_id() == 1)
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offset = 0;
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else
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offset = (uv_blade_processor_id() * L1_CACHE_BYTES) % PAGE_SIZE;
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return (u64)uv_read_local_mmr(UVH_RTC | offset);
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}
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/*
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* Program the next event, relative to now
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*/
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static int uv_rtc_next_event(unsigned long delta,
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struct clock_event_device *ced)
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{
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int ced_cpu = cpumask_first(ced->cpumask);
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return uv_rtc_set_timer(ced_cpu, delta + uv_read_rtc(NULL));
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}
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/*
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* Shutdown the RTC timer
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*/
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static int uv_rtc_shutdown(struct clock_event_device *evt)
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{
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int ced_cpu = cpumask_first(evt->cpumask);
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uv_rtc_unset_timer(ced_cpu, 1);
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return 0;
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}
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static void uv_rtc_interrupt(void)
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{
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int cpu = smp_processor_id();
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struct clock_event_device *ced = &per_cpu(cpu_ced, cpu);
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if (!ced || !ced->event_handler)
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return;
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if (uv_rtc_unset_timer(cpu, 0) != 1)
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return;
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ced->event_handler(ced);
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}
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static int __init uv_enable_evt_rtc(char *str)
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{
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uv_rtc_evt_enable = 1;
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return 1;
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}
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__setup("uvrtcevt", uv_enable_evt_rtc);
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static __init void uv_rtc_register_clockevents(struct work_struct *dummy)
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{
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struct clock_event_device *ced = this_cpu_ptr(&cpu_ced);
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*ced = clock_event_device_uv;
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ced->cpumask = cpumask_of(smp_processor_id());
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clockevents_register_device(ced);
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}
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static __init int uv_rtc_setup_clock(void)
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{
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int rc;
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if (!is_uv_system())
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return -ENODEV;
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rc = clocksource_register_hz(&clocksource_uv, sn_rtc_cycles_per_second);
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if (rc)
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printk(KERN_INFO "UV RTC clocksource failed rc %d\n", rc);
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else
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printk(KERN_INFO "UV RTC clocksource registered freq %lu MHz\n",
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sn_rtc_cycles_per_second/(unsigned long)1E6);
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if (rc || !uv_rtc_evt_enable || x86_platform_ipi_callback)
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return rc;
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/* Setup and register clockevents */
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rc = uv_rtc_allocate_timers();
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if (rc)
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goto error;
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x86_platform_ipi_callback = uv_rtc_interrupt;
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clock_event_device_uv.mult = div_sc(sn_rtc_cycles_per_second,
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NSEC_PER_SEC, clock_event_device_uv.shift);
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clock_event_device_uv.min_delta_ns = NSEC_PER_SEC /
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sn_rtc_cycles_per_second;
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clock_event_device_uv.min_delta_ticks = 1;
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clock_event_device_uv.max_delta_ns = clocksource_uv.mask *
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(NSEC_PER_SEC / sn_rtc_cycles_per_second);
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clock_event_device_uv.max_delta_ticks = clocksource_uv.mask;
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rc = schedule_on_each_cpu(uv_rtc_register_clockevents);
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if (rc) {
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x86_platform_ipi_callback = NULL;
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uv_rtc_deallocate_timers();
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goto error;
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}
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printk(KERN_INFO "UV RTC clockevents registered\n");
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return 0;
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error:
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clocksource_unregister(&clocksource_uv);
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printk(KERN_INFO "UV RTC clockevents failed rc %d\n", rc);
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return rc;
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}
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arch_initcall(uv_rtc_setup_clock);
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