[PATCH] sched: disable preempt in idle tasks

[linux-2.6.git] / arch / powerpc / platforms / pseries / setup.c

/*
 *  64-bit pSeries and RS/6000 setup code.
 *
 *  Copyright (C) 1995  Linus Torvalds
 *  Adapted from 'alpha' version by Gary Thomas
 *  Modified by Cort Dougan (cort@cs.nmt.edu)
 *  Modified by PPC64 Team, IBM Corp
 *
 * 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 the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

/*
 * bootup setup stuff..
 */

#undef DEBUG

#include <linux/config.h>
#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/tty.h>
#include <linux/major.h>
#include <linux/interrupt.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/console.h>
#include <linux/pci.h>
#include <linux/utsname.h>
#include <linux/adb.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/seq_file.h>
#include <linux/root_dev.h>

#include <asm/mmu.h>
#include <asm/processor.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/prom.h>
#include <asm/rtas.h>
#include <asm/pci-bridge.h>
#include <asm/iommu.h>
#include <asm/dma.h>
#include <asm/machdep.h>
#include <asm/irq.h>
#include <asm/time.h>
#include <asm/nvram.h>
#include "xics.h"
#include <asm/firmware.h>
#include <asm/pmc.h>
#include <asm/mpic.h>
#include <asm/ppc-pci.h>
#include <asm/i8259.h>
#include <asm/udbg.h>
#include <asm/smp.h>

#include "plpar_wrappers.h"

#ifdef DEBUG
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif

extern void find_udbg_vterm(void);
extern void system_reset_fwnmi(void);   /* from head.S */
extern void machine_check_fwnmi(void);  /* from head.S */
extern void generic_find_legacy_serial_ports(u64 *physport,
                unsigned int *default_speed);

int fwnmi_active;  /* TRUE if an FWNMI handler is present */

extern void pSeries_system_reset_exception(struct pt_regs *regs);
extern int pSeries_machine_check_exception(struct pt_regs *regs);

static void pseries_shared_idle(void);
static void pseries_dedicated_idle(void);

struct mpic *pSeries_mpic;

void pSeries_show_cpuinfo(struct seq_file *m)
{
        struct device_node *root;
        const char *model = "";

        root = of_find_node_by_path("/");
        if (root)
                model = get_property(root, "model", NULL);
        seq_printf(m, "machine\t\t: CHRP %s\n", model);
        of_node_put(root);
}

/* Initialize firmware assisted non-maskable interrupts if
 * the firmware supports this feature.
 *
 */
static void __init fwnmi_init(void)
{
        int ret;
        int ibm_nmi_register = rtas_token("ibm,nmi-register");
        if (ibm_nmi_register == RTAS_UNKNOWN_SERVICE)
                return;
        ret = rtas_call(ibm_nmi_register, 2, 1, NULL,
                        __pa((unsigned long)system_reset_fwnmi),
                        __pa((unsigned long)machine_check_fwnmi));
        if (ret == 0)
                fwnmi_active = 1;
}

static void __init pSeries_init_mpic(void)
{
        unsigned int *addrp;
        struct device_node *np;
        unsigned long intack = 0;

        /* All ISUs are setup, complete initialization */
        mpic_init(pSeries_mpic);

        /* Check what kind of cascade ACK we have */
        if (!(np = of_find_node_by_name(NULL, "pci"))
            || !(addrp = (unsigned int *)
                 get_property(np, "8259-interrupt-acknowledge", NULL)))
                printk(KERN_ERR "Cannot find pci to get ack address\n");
        else
                intack = addrp[prom_n_addr_cells(np)-1];
        of_node_put(np);

        /* Setup the legacy interrupts & controller */
        i8259_init(intack, 0);

        /* Hook cascade to mpic */
        mpic_setup_cascade(NUM_ISA_INTERRUPTS, i8259_irq_cascade, NULL);
}

static void __init pSeries_setup_mpic(void)
{
        unsigned int *opprop;
        unsigned long openpic_addr = 0;
        unsigned char senses[NR_IRQS - NUM_ISA_INTERRUPTS];
        struct device_node *root;
        int irq_count;

        /* Find the Open PIC if present */
        root = of_find_node_by_path("/");
        opprop = (unsigned int *) get_property(root, "platform-open-pic", NULL);
        if (opprop != 0) {
                int n = prom_n_addr_cells(root);

                for (openpic_addr = 0; n > 0; --n)
                        openpic_addr = (openpic_addr << 32) + *opprop++;
                printk(KERN_DEBUG "OpenPIC addr: %lx\n", openpic_addr);
        }
        of_node_put(root);

        BUG_ON(openpic_addr == 0);

        /* Get the sense values from OF */
        prom_get_irq_senses(senses, NUM_ISA_INTERRUPTS, NR_IRQS);
        
        /* Setup the openpic driver */
        irq_count = NR_IRQS - NUM_ISA_INTERRUPTS - 4; /* leave room for IPIs */
        pSeries_mpic = mpic_alloc(openpic_addr, MPIC_PRIMARY,
                                  16, 16, irq_count, /* isu size, irq offset, irq count */ 
                                  NR_IRQS - 4, /* ipi offset */
                                  senses, irq_count, /* sense & sense size */
                                  " MPIC     ");
}

static void pseries_lpar_enable_pmcs(void)
{
        unsigned long set, reset;

        power4_enable_pmcs();

        set = 1UL << 63;
        reset = 0;
        plpar_hcall_norets(H_PERFMON, set, reset);

        /* instruct hypervisor to maintain PMCs */
        if (firmware_has_feature(FW_FEATURE_SPLPAR))
                get_paca()->lppaca.pmcregs_in_use = 1;
}

static void __init pSeries_setup_arch(void)
{
        /* Fixup ppc_md depending on the type of interrupt controller */
        if (ppc64_interrupt_controller == IC_OPEN_PIC) {
                ppc_md.init_IRQ       = pSeries_init_mpic;
                ppc_md.get_irq        = mpic_get_irq;
                ppc_md.cpu_irq_down   = mpic_teardown_this_cpu;
                /* Allocate the mpic now, so that find_and_init_phbs() can
                 * fill the ISUs */
                pSeries_setup_mpic();
        } else {
                ppc_md.init_IRQ       = xics_init_IRQ;
                ppc_md.get_irq        = xics_get_irq;
                ppc_md.cpu_irq_down   = xics_teardown_cpu;
        }

#ifdef CONFIG_SMP
        smp_init_pSeries();
#endif
        /* openpic global configuration register (64-bit format). */
        /* openpic Interrupt Source Unit pointer (64-bit format). */
        /* python0 facility area (mmio) (64-bit format) REAL address. */

        /* init to some ~sane value until calibrate_delay() runs */
        loops_per_jiffy = 50000000;

        if (ROOT_DEV == 0) {
                printk("No ramdisk, default root is /dev/sda2\n");
                ROOT_DEV = Root_SDA2;
        }

        fwnmi_init();

        /* Find and initialize PCI host bridges */
        init_pci_config_tokens();
        find_and_init_phbs();
        eeh_init();

        pSeries_nvram_init();

        /* Choose an idle loop */
        if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
                vpa_init(boot_cpuid);
                if (get_paca()->lppaca.shared_proc) {
                        printk(KERN_INFO "Using shared processor idle loop\n");
                        ppc_md.idle_loop = pseries_shared_idle;
                } else {
                        printk(KERN_INFO "Using dedicated idle loop\n");
                        ppc_md.idle_loop = pseries_dedicated_idle;
                }
        } else {
                printk(KERN_INFO "Using default idle loop\n");
                ppc_md.idle_loop = default_idle;
        }

        if (systemcfg->platform & PLATFORM_LPAR)
                ppc_md.enable_pmcs = pseries_lpar_enable_pmcs;
        else
                ppc_md.enable_pmcs = power4_enable_pmcs;
}

static int __init pSeries_init_panel(void)
{
        /* Manually leave the kernel version on the panel. */
        ppc_md.progress("Linux ppc64\n", 0);
        ppc_md.progress(system_utsname.version, 0);

        return 0;
}
arch_initcall(pSeries_init_panel);


/* Build up the ppc64_firmware_features bitmask field
 * using contents of device-tree/ibm,hypertas-functions.
 * Ultimately this functionality may be moved into prom.c prom_init().
 */
static void __init fw_feature_init(void)
{
        struct device_node * dn;
        char * hypertas;
        unsigned int len;

        DBG(" -> fw_feature_init()\n");

        ppc64_firmware_features = 0;
        dn = of_find_node_by_path("/rtas");
        if (dn == NULL) {
                printk(KERN_ERR "WARNING ! Cannot find RTAS in device-tree !\n");
                goto no_rtas;
        }

        hypertas = get_property(dn, "ibm,hypertas-functions", &len);
        if (hypertas) {
                while (len > 0){
                        int i, hypertas_len;
                        /* check value against table of strings */
                        for(i=0; i < FIRMWARE_MAX_FEATURES ;i++) {
                                if ((firmware_features_table[i].name) &&
                                    (strcmp(firmware_features_table[i].name,hypertas))==0) {
                                        /* we have a match */
                                        ppc64_firmware_features |= 
                                                (firmware_features_table[i].val);
                                        break;
                                } 
                        }
                        hypertas_len = strlen(hypertas);
                        len -= hypertas_len +1;
                        hypertas+= hypertas_len +1;
                }
        }

        of_node_put(dn);
 no_rtas:
        printk(KERN_INFO "firmware_features = 0x%lx\n", 
               ppc64_firmware_features);

        DBG(" <- fw_feature_init()\n");
}


static  void __init pSeries_discover_pic(void)
{
        struct device_node *np;
        char *typep;

        /*
         * Setup interrupt mapping options that are needed for finish_device_tree
         * to properly parse the OF interrupt tree & do the virtual irq mapping
         */
        __irq_offset_value = NUM_ISA_INTERRUPTS;
        ppc64_interrupt_controller = IC_INVALID;
        for (np = NULL; (np = of_find_node_by_name(np, "interrupt-controller"));) {
                typep = (char *)get_property(np, "compatible", NULL);
                if (strstr(typep, "open-pic"))
                        ppc64_interrupt_controller = IC_OPEN_PIC;
                else if (strstr(typep, "ppc-xicp"))
                        ppc64_interrupt_controller = IC_PPC_XIC;
                else
                        printk("pSeries_discover_pic: failed to recognize"
                               " interrupt-controller\n");
                break;
        }
}

static void pSeries_mach_cpu_die(void)
{
        local_irq_disable();
        idle_task_exit();
        /* Some hardware requires clearing the CPPR, while other hardware does not
         * it is safe either way
         */
        pSeriesLP_cppr_info(0, 0);
        rtas_stop_self();
        /* Should never get here... */
        BUG();
        for(;;);
}

static int pseries_set_dabr(unsigned long dabr)
{
        return plpar_hcall_norets(H_SET_DABR, dabr);
}

static int pseries_set_xdabr(unsigned long dabr)
{
        /* We want to catch accesses from kernel and userspace */
        return plpar_hcall_norets(H_SET_XDABR, dabr,
                        H_DABRX_KERNEL | H_DABRX_USER);
}

/*
 * Early initialization.  Relocation is on but do not reference unbolted pages
 */
static void __init pSeries_init_early(void)
{
        void *comport;
        int iommu_off = 0;
        unsigned int default_speed;
        u64 physport;

        DBG(" -> pSeries_init_early()\n");

        fw_feature_init();
        
        if (systemcfg->platform & PLATFORM_LPAR)
                hpte_init_lpar();
        else {
                hpte_init_native();
                iommu_off = (of_chosen &&
                             get_property(of_chosen, "linux,iommu-off", NULL));
        }

        generic_find_legacy_serial_ports(&physport, &default_speed);

        if (systemcfg->platform & PLATFORM_LPAR)
                find_udbg_vterm();
        else if (physport) {
                /* Map the uart for udbg. */
                comport = (void *)ioremap(physport, 16);
                udbg_init_uart(comport, default_speed);

                DBG("Hello World !\n");
        }

        if (firmware_has_feature(FW_FEATURE_DABR))
                ppc_md.set_dabr = pseries_set_dabr;
        else if (firmware_has_feature(FW_FEATURE_XDABR))
                ppc_md.set_dabr = pseries_set_xdabr;

        iommu_init_early_pSeries();

        pSeries_discover_pic();

        DBG(" <- pSeries_init_early()\n");
}


static int pSeries_check_legacy_ioport(unsigned int baseport)
{
        struct device_node *np;

#define I8042_DATA_REG  0x60
#define FDC_BASE        0x3f0


        switch(baseport) {
        case I8042_DATA_REG:
                np = of_find_node_by_type(NULL, "8042");
                if (np == NULL)
                        return -ENODEV;
                of_node_put(np);
                break;
        case FDC_BASE:
                np = of_find_node_by_type(NULL, "fdc");
                if (np == NULL)
                        return -ENODEV;
                of_node_put(np);
                break;
        }
        return 0;
}

/*
 * Called very early, MMU is off, device-tree isn't unflattened
 */
extern struct machdep_calls pSeries_md;

static int __init pSeries_probe(int platform)
{
        if (platform != PLATFORM_PSERIES &&
            platform != PLATFORM_PSERIES_LPAR)
                return 0;

        /* if we have some ppc_md fixups for LPAR to do, do
         * it here ...
         */

        return 1;
}

DECLARE_PER_CPU(unsigned long, smt_snooze_delay);

static inline void dedicated_idle_sleep(unsigned int cpu)
{
        struct paca_struct *ppaca = &paca[cpu ^ 1];

        /* Only sleep if the other thread is not idle */
        if (!(ppaca->lppaca.idle)) {
                local_irq_disable();

                /*
                 * We are about to sleep the thread and so wont be polling any
                 * more.
                 */
                clear_thread_flag(TIF_POLLING_NRFLAG);

                /*
                 * SMT dynamic mode. Cede will result in this thread going
                 * dormant, if the partner thread is still doing work.  Thread
                 * wakes up if partner goes idle, an interrupt is presented, or
                 * a prod occurs.  Returning from the cede enables external
                 * interrupts.
                 */
                if (!need_resched())
                        cede_processor();
                else
                        local_irq_enable();
        } else {
                /*
                 * Give the HV an opportunity at the processor, since we are
                 * not doing any work.
                 */
                poll_pending();
        }
}

static void pseries_dedicated_idle(void)
{ 
        long oldval;
        struct paca_struct *lpaca = get_paca();
        unsigned int cpu = smp_processor_id();
        unsigned long start_snooze;
        unsigned long *smt_snooze_delay = &__get_cpu_var(smt_snooze_delay);

        while (1) {
                /*
                 * Indicate to the HV that we are idle. Now would be
                 * a good time to find other work to dispatch.
                 */
                lpaca->lppaca.idle = 1;

                oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
                if (!oldval) {
                        set_thread_flag(TIF_POLLING_NRFLAG);

                        start_snooze = __get_tb() +
                                *smt_snooze_delay * tb_ticks_per_usec;

                        while (!need_resched() && !cpu_is_offline(cpu)) {
                                ppc64_runlatch_off();

                                /*
                                 * Go into low thread priority and possibly
                                 * low power mode.
                                 */
                                HMT_low();
                                HMT_very_low();

                                if (*smt_snooze_delay != 0 &&
                                    __get_tb() > start_snooze) {
                                        HMT_medium();
                                        dedicated_idle_sleep(cpu);
                                }

                        }

                        HMT_medium();
                        clear_thread_flag(TIF_POLLING_NRFLAG);
                } else {
                        set_need_resched();
                }

                lpaca->lppaca.idle = 0;
                ppc64_runlatch_on();

                preempt_enable_no_resched();
                schedule();
                preempt_disable();

                if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)
                        cpu_die();
        }
}

static void pseries_shared_idle(void)
{
        struct paca_struct *lpaca = get_paca();
        unsigned int cpu = smp_processor_id();

        while (1) {
                /*
                 * Indicate to the HV that we are idle. Now would be
                 * a good time to find other work to dispatch.
                 */
                lpaca->lppaca.idle = 1;

                while (!need_resched() && !cpu_is_offline(cpu)) {
                        local_irq_disable();
                        ppc64_runlatch_off();

                        /*
                         * Yield the processor to the hypervisor.  We return if
                         * an external interrupt occurs (which are driven prior
                         * to returning here) or if a prod occurs from another
                         * processor. When returning here, external interrupts
                         * are enabled.
                         *
                         * Check need_resched() again with interrupts disabled
                         * to avoid a race.
                         */
                        if (!need_resched())
                                cede_processor();
                        else
                                local_irq_enable();

                        HMT_medium();
                }

                lpaca->lppaca.idle = 0;
                ppc64_runlatch_on();

                preempt_enable_no_resched();
                schedule();
                preempt_disable();

                if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)
                        cpu_die();
        }
}

static int pSeries_pci_probe_mode(struct pci_bus *bus)
{
        if (systemcfg->platform & PLATFORM_LPAR)
                return PCI_PROBE_DEVTREE;
        return PCI_PROBE_NORMAL;
}

struct machdep_calls __initdata pSeries_md = {
        .probe                  = pSeries_probe,
        .setup_arch             = pSeries_setup_arch,
        .init_early             = pSeries_init_early,
        .show_cpuinfo           = pSeries_show_cpuinfo,
        .log_error              = pSeries_log_error,
        .pcibios_fixup          = pSeries_final_fixup,
        .pci_probe_mode         = pSeries_pci_probe_mode,
        .irq_bus_setup          = pSeries_irq_bus_setup,
        .restart                = rtas_restart,
        .power_off              = rtas_power_off,
        .halt                   = rtas_halt,
        .panic                  = rtas_os_term,
        .cpu_die                = pSeries_mach_cpu_die,
        .get_boot_time          = rtas_get_boot_time,
        .get_rtc_time           = rtas_get_rtc_time,
        .set_rtc_time           = rtas_set_rtc_time,
        .calibrate_decr         = generic_calibrate_decr,
        .progress               = rtas_progress,
        .check_legacy_ioport    = pSeries_check_legacy_ioport,
        .system_reset_exception = pSeries_system_reset_exception,
        .machine_check_exception = pSeries_machine_check_exception,
};