ACPI: pci_root: simplify list traversals

[linux-2.6/linux-acpi-2.6.git] / drivers / misc / sgi-gru / grukservices.c

/*
 * SN Platform GRU Driver
 *
 *              KERNEL SERVICES THAT USE THE GRU
 *
 *  Copyright (c) 2008 Silicon Graphics, Inc.  All Rights Reserved.
 *
 *  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.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/smp_lock.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
#include <linux/proc_fs.h>
#include <linux/interrupt.h>
#include <linux/uaccess.h>
#include "gru.h"
#include "grulib.h"
#include "grutables.h"
#include "grukservices.h"
#include "gru_instructions.h"
#include <asm/uv/uv_hub.h>

/*
 * Kernel GRU Usage
 *
 * The following is an interim algorithm for management of kernel GRU
 * resources. This will likely be replaced when we better understand the
 * kernel/user requirements.
 *
 * At boot time, the kernel permanently reserves a fixed number of
 * CBRs/DSRs for each cpu to use. The resources are all taken from
 * the GRU chiplet 1 on the blade. This leaves the full set of resources
 * of chiplet 0 available to be allocated to a single user.
 */

/* Blade percpu resources PERMANENTLY reserved for kernel use */
#define GRU_NUM_KERNEL_CBR      1
#define GRU_NUM_KERNEL_DSR_BYTES 256
#define GRU_NUM_KERNEL_DSR_CL   (GRU_NUM_KERNEL_DSR_BYTES /             \
                                        GRU_CACHE_LINE_BYTES)
#define KERNEL_CTXNUM           15

/* GRU instruction attributes for all instructions */
#define IMA                     IMA_CB_DELAY

/* GRU cacheline size is always 64 bytes - even on arches with 128 byte lines */
#define __gru_cacheline_aligned__                               \
        __attribute__((__aligned__(GRU_CACHE_LINE_BYTES)))

#define MAGIC   0x1234567887654321UL

/* Default retry count for GRU errors on kernel instructions */
#define EXCEPTION_RETRY_LIMIT   3

/* Status of message queue sections */
#define MQS_EMPTY               0
#define MQS_FULL                1
#define MQS_NOOP                2

/*----------------- RESOURCE MANAGEMENT -------------------------------------*/
/* optimized for x86_64 */
struct message_queue {
        union gru_mesqhead      head __gru_cacheline_aligned__; /* CL 0 */
        int                     qlines;                         /* DW 1 */
        long                    hstatus[2];
        void                    *next __gru_cacheline_aligned__;/* CL 1 */
        void                    *limit;
        void                    *start;
        void                    *start2;
        char                    data ____cacheline_aligned;     /* CL 2 */
};

/* First word in every message - used by mesq interface */
struct message_header {
        char    present;
        char    present2;
        char    lines;
        char    fill;
};

#define HSTATUS(mq, h)  ((mq) + offsetof(struct message_queue, hstatus[h]))

static int gru_get_cpu_resources(int dsr_bytes, void **cb, void **dsr)
{
        struct gru_blade_state *bs;
        int lcpu;

        BUG_ON(dsr_bytes > GRU_NUM_KERNEL_DSR_BYTES);
        preempt_disable();
        bs = gru_base[uv_numa_blade_id()];
        lcpu = uv_blade_processor_id();
        *cb = bs->kernel_cb + lcpu * GRU_HANDLE_STRIDE;
        *dsr = bs->kernel_dsr + lcpu * GRU_NUM_KERNEL_DSR_BYTES;
        return 0;
}

static void gru_free_cpu_resources(void *cb, void *dsr)
{
        preempt_enable();
}

int gru_get_cb_exception_detail(void *cb,
                struct control_block_extended_exc_detail *excdet)
{
        struct gru_control_block_extended *cbe;

        cbe = get_cbe(GRUBASE(cb), get_cb_number(cb));
        prefetchw(cbe); /* Harmless on hardware, required for emulator */
        excdet->opc = cbe->opccpy;
        excdet->exopc = cbe->exopccpy;
        excdet->ecause = cbe->ecause;
        excdet->exceptdet0 = cbe->idef1upd;
        excdet->exceptdet1 = cbe->idef3upd;
        return 0;
}

char *gru_get_cb_exception_detail_str(int ret, void *cb,
                                      char *buf, int size)
{
        struct gru_control_block_status *gen = (void *)cb;
        struct control_block_extended_exc_detail excdet;

        if (ret > 0 && gen->istatus == CBS_EXCEPTION) {
                gru_get_cb_exception_detail(cb, &excdet);
                snprintf(buf, size,
                        "GRU exception: cb %p, opc %d, exopc %d, ecause 0x%x,"
                        "excdet0 0x%lx, excdet1 0x%x",
                        gen, excdet.opc, excdet.exopc, excdet.ecause,
                        excdet.exceptdet0, excdet.exceptdet1);
        } else {
                snprintf(buf, size, "No exception");
        }
        return buf;
}

static int gru_wait_idle_or_exception(struct gru_control_block_status *gen)
{
        while (gen->istatus >= CBS_ACTIVE) {
                cpu_relax();
                barrier();
        }
        return gen->istatus;
}

static int gru_retry_exception(void *cb)
{
        struct gru_control_block_status *gen = (void *)cb;
        struct control_block_extended_exc_detail excdet;
        int retry = EXCEPTION_RETRY_LIMIT;

        while (1)  {
                if (gru_get_cb_message_queue_substatus(cb))
                        break;
                if (gru_wait_idle_or_exception(gen) == CBS_IDLE)
                        return CBS_IDLE;

                gru_get_cb_exception_detail(cb, &excdet);
                if (excdet.ecause & ~EXCEPTION_RETRY_BITS)
                        break;
                if (retry-- == 0)
                        break;
                gen->icmd = 1;
                gru_flush_cache(gen);
        }
        return CBS_EXCEPTION;
}

int gru_check_status_proc(void *cb)
{
        struct gru_control_block_status *gen = (void *)cb;
        int ret;

        ret = gen->istatus;
        if (ret != CBS_EXCEPTION)
                return ret;
        return gru_retry_exception(cb);

}

int gru_wait_proc(void *cb)
{
        struct gru_control_block_status *gen = (void *)cb;
        int ret;

        ret = gru_wait_idle_or_exception(gen);
        if (ret == CBS_EXCEPTION)
                ret = gru_retry_exception(cb);

        return ret;
}

void gru_abort(int ret, void *cb, char *str)
{
        char buf[GRU_EXC_STR_SIZE];

        panic("GRU FATAL ERROR: %s - %s\n", str,
              gru_get_cb_exception_detail_str(ret, cb, buf, sizeof(buf)));
}

void gru_wait_abort_proc(void *cb)
{
        int ret;

        ret = gru_wait_proc(cb);
        if (ret)
                gru_abort(ret, cb, "gru_wait_abort");
}


/*------------------------------ MESSAGE QUEUES -----------------------------*/

/* Internal status . These are NOT returned to the user. */
#define MQIE_AGAIN              -1      /* try again */


/*
 * Save/restore the "present" flag that is in the second line of 2-line
 * messages
 */
static inline int get_present2(void *p)
{
        struct message_header *mhdr = p + GRU_CACHE_LINE_BYTES;
        return mhdr->present;
}

static inline void restore_present2(void *p, int val)
{
        struct message_header *mhdr = p + GRU_CACHE_LINE_BYTES;
        mhdr->present = val;
}

/*
 * Create a message queue.
 *      qlines - message queue size in cache lines. Includes 2-line header.
 */
int gru_create_message_queue(struct gru_message_queue_desc *mqd,
                void *p, unsigned int bytes, int nasid, int vector, int apicid)
{
        struct message_queue *mq = p;
        unsigned int qlines;

        qlines = bytes / GRU_CACHE_LINE_BYTES - 2;
        memset(mq, 0, bytes);
        mq->start = &mq->data;
        mq->start2 = &mq->data + (qlines / 2 - 1) * GRU_CACHE_LINE_BYTES;
        mq->next = &mq->data;
        mq->limit = &mq->data + (qlines - 2) * GRU_CACHE_LINE_BYTES;
        mq->qlines = qlines;
        mq->hstatus[0] = 0;
        mq->hstatus[1] = 1;
        mq->head = gru_mesq_head(2, qlines / 2 + 1);
        mqd->mq = mq;
        mqd->mq_gpa = uv_gpa(mq);
        mqd->qlines = qlines;
        mqd->interrupt_pnode = UV_NASID_TO_PNODE(nasid);
        mqd->interrupt_vector = vector;
        mqd->interrupt_apicid = apicid;
        return 0;
}
EXPORT_SYMBOL_GPL(gru_create_message_queue);

/*
 * Send a NOOP message to a message queue
 *      Returns:
 *               0 - if queue is full after the send. This is the normal case
 *                   but various races can change this.
 *              -1 - if mesq sent successfully but queue not full
 *              >0 - unexpected error. MQE_xxx returned
 */
static int send_noop_message(void *cb, struct gru_message_queue_desc *mqd,
                                void *mesg)
{
        const struct message_header noop_header = {
                                        .present = MQS_NOOP, .lines = 1};
        unsigned long m;
        int substatus, ret;
        struct message_header save_mhdr, *mhdr = mesg;

        STAT(mesq_noop);
        save_mhdr = *mhdr;
        *mhdr = noop_header;
        gru_mesq(cb, mqd->mq_gpa, gru_get_tri(mhdr), 1, IMA);
        ret = gru_wait(cb);

        if (ret) {
                substatus = gru_get_cb_message_queue_substatus(cb);
                switch (substatus) {
                case CBSS_NO_ERROR:
                        STAT(mesq_noop_unexpected_error);
                        ret = MQE_UNEXPECTED_CB_ERR;
                        break;
                case CBSS_LB_OVERFLOWED:
                        STAT(mesq_noop_lb_overflow);
                        ret = MQE_CONGESTION;
                        break;
                case CBSS_QLIMIT_REACHED:
                        STAT(mesq_noop_qlimit_reached);
                        ret = 0;
                        break;
                case CBSS_AMO_NACKED:
                        STAT(mesq_noop_amo_nacked);
                        ret = MQE_CONGESTION;
                        break;
                case CBSS_PUT_NACKED:
                        STAT(mesq_noop_put_nacked);
                        m = mqd->mq_gpa + (gru_get_amo_value_head(cb) << 6);
                        gru_vstore(cb, m, gru_get_tri(mesg), XTYPE_CL, 1, 1,
                                                IMA);
                        if (gru_wait(cb) == CBS_IDLE)
                                ret = MQIE_AGAIN;
                        else
                                ret = MQE_UNEXPECTED_CB_ERR;
                        break;
                case CBSS_PAGE_OVERFLOW:
                default:
                        BUG();
                }
        }
        *mhdr = save_mhdr;
        return ret;
}

/*
 * Handle a gru_mesq full.
 */
static int send_message_queue_full(void *cb, struct gru_message_queue_desc *mqd,
                                void *mesg, int lines)
{
        union gru_mesqhead mqh;
        unsigned int limit, head;
        unsigned long avalue;
        int half, qlines;

        /* Determine if switching to first/second half of q */
        avalue = gru_get_amo_value(cb);
        head = gru_get_amo_value_head(cb);
        limit = gru_get_amo_value_limit(cb);

        qlines = mqd->qlines;
        half = (limit != qlines);

        if (half)
                mqh = gru_mesq_head(qlines / 2 + 1, qlines);
        else
                mqh = gru_mesq_head(2, qlines / 2 + 1);

        /* Try to get lock for switching head pointer */
        gru_gamir(cb, EOP_IR_CLR, HSTATUS(mqd->mq_gpa, half), XTYPE_DW, IMA);
        if (gru_wait(cb) != CBS_IDLE)
                goto cberr;
        if (!gru_get_amo_value(cb)) {
                STAT(mesq_qf_locked);
                return MQE_QUEUE_FULL;
        }

        /* Got the lock. Send optional NOP if queue not full, */
        if (head != limit) {
                if (send_noop_message(cb, mqd, mesg)) {
                        gru_gamir(cb, EOP_IR_INC, HSTATUS(mqd->mq_gpa, half),
                                        XTYPE_DW, IMA);
                        if (gru_wait(cb) != CBS_IDLE)
                                goto cberr;
                        STAT(mesq_qf_noop_not_full);
                        return MQIE_AGAIN;
                }
                avalue++;
        }

        /* Then flip queuehead to other half of queue. */
        gru_gamer(cb, EOP_ERR_CSWAP, mqd->mq_gpa, XTYPE_DW, mqh.val, avalue,
                                                        IMA);
        if (gru_wait(cb) != CBS_IDLE)
                goto cberr;

        /* If not successfully in swapping queue head, clear the hstatus lock */
        if (gru_get_amo_value(cb) != avalue) {
                STAT(mesq_qf_switch_head_failed);
                gru_gamir(cb, EOP_IR_INC, HSTATUS(mqd->mq_gpa, half), XTYPE_DW,
                                                        IMA);
                if (gru_wait(cb) != CBS_IDLE)
                        goto cberr;
        }
        return MQIE_AGAIN;
cberr:
        STAT(mesq_qf_unexpected_error);
        return MQE_UNEXPECTED_CB_ERR;
}

/*
 * Send a cross-partition interrupt to the SSI that contains the target
 * message queue. Normally, the interrupt is automatically delivered by hardware
 * but some error conditions require explicit delivery.
 */
static void send_message_queue_interrupt(struct gru_message_queue_desc *mqd)
{
        if (mqd->interrupt_vector)
                uv_hub_send_ipi(mqd->interrupt_pnode, mqd->interrupt_apicid,
                                mqd->interrupt_vector);
}


/*
 * Handle a gru_mesq failure. Some of these failures are software recoverable
 * or retryable.
 */
static int send_message_failure(void *cb, struct gru_message_queue_desc *mqd,
                                void *mesg, int lines)
{
        int substatus, ret = 0;
        unsigned long m;

        substatus = gru_get_cb_message_queue_substatus(cb);
        switch (substatus) {
        case CBSS_NO_ERROR:
                STAT(mesq_send_unexpected_error);
                ret = MQE_UNEXPECTED_CB_ERR;
                break;
        case CBSS_LB_OVERFLOWED:
                STAT(mesq_send_lb_overflow);
                ret = MQE_CONGESTION;
                break;
        case CBSS_QLIMIT_REACHED:
                STAT(mesq_send_qlimit_reached);
                ret = send_message_queue_full(cb, mqd, mesg, lines);
                break;
        case CBSS_AMO_NACKED:
                STAT(mesq_send_amo_nacked);
                ret = MQE_CONGESTION;
                break;
        case CBSS_PUT_NACKED:
                STAT(mesq_send_put_nacked);
                m = mqd->mq_gpa + (gru_get_amo_value_head(cb) << 6);
                gru_vstore(cb, m, gru_get_tri(mesg), XTYPE_CL, lines, 1, IMA);
                if (gru_wait(cb) == CBS_IDLE) {
                        ret = MQE_OK;
                        send_message_queue_interrupt(mqd);
                } else {
                        ret = MQE_UNEXPECTED_CB_ERR;
                }
                break;
        default:
                BUG();
        }
        return ret;
}

/*
 * Send a message to a message queue
 *      mqd     message queue descriptor
 *      mesg    message. ust be vaddr within a GSEG
 *      bytes   message size (<= 2 CL)
 */
int gru_send_message_gpa(struct gru_message_queue_desc *mqd, void *mesg,
                                unsigned int bytes)
{
        struct message_header *mhdr;
        void *cb;
        void *dsr;
        int istatus, clines, ret;

        STAT(mesq_send);
        BUG_ON(bytes < sizeof(int) || bytes > 2 * GRU_CACHE_LINE_BYTES);

        clines = DIV_ROUND_UP(bytes, GRU_CACHE_LINE_BYTES);
        if (gru_get_cpu_resources(bytes, &cb, &dsr))
                return MQE_BUG_NO_RESOURCES;
        memcpy(dsr, mesg, bytes);
        mhdr = dsr;
        mhdr->present = MQS_FULL;
        mhdr->lines = clines;
        if (clines == 2) {
                mhdr->present2 = get_present2(mhdr);
                restore_present2(mhdr, MQS_FULL);
        }

        do {
                ret = MQE_OK;
                gru_mesq(cb, mqd->mq_gpa, gru_get_tri(mhdr), clines, IMA);
                istatus = gru_wait(cb);
                if (istatus != CBS_IDLE)
                        ret = send_message_failure(cb, mqd, dsr, clines);
        } while (ret == MQIE_AGAIN);
        gru_free_cpu_resources(cb, dsr);

        if (ret)
                STAT(mesq_send_failed);
        return ret;
}
EXPORT_SYMBOL_GPL(gru_send_message_gpa);

/*
 * Advance the receive pointer for the queue to the next message.
 */
void gru_free_message(struct gru_message_queue_desc *mqd, void *mesg)
{
        struct message_queue *mq = mqd->mq;
        struct message_header *mhdr = mq->next;
        void *next, *pnext;
        int half = -1;
        int lines = mhdr->lines;

        if (lines == 2)
                restore_present2(mhdr, MQS_EMPTY);
        mhdr->present = MQS_EMPTY;

        pnext = mq->next;
        next = pnext + GRU_CACHE_LINE_BYTES * lines;
        if (next == mq->limit) {
                next = mq->start;
                half = 1;
        } else if (pnext < mq->start2 && next >= mq->start2) {
                half = 0;
        }

        if (half >= 0)
                mq->hstatus[half] = 1;
        mq->next = next;
}
EXPORT_SYMBOL_GPL(gru_free_message);

/*
 * Get next message from message queue. Return NULL if no message
 * present. User must call next_message() to move to next message.
 *      rmq     message queue
 */
void *gru_get_next_message(struct gru_message_queue_desc *mqd)
{
        struct message_queue *mq = mqd->mq;
        struct message_header *mhdr = mq->next;
        int present = mhdr->present;

        /* skip NOOP messages */
        STAT(mesq_receive);
        while (present == MQS_NOOP) {
                gru_free_message(mqd, mhdr);
                mhdr = mq->next;
                present = mhdr->present;
        }

        /* Wait for both halves of 2 line messages */
        if (present == MQS_FULL && mhdr->lines == 2 &&
                                get_present2(mhdr) == MQS_EMPTY)
                present = MQS_EMPTY;

        if (!present) {
                STAT(mesq_receive_none);
                return NULL;
        }

        if (mhdr->lines == 2)
                restore_present2(mhdr, mhdr->present2);

        return mhdr;
}
EXPORT_SYMBOL_GPL(gru_get_next_message);

/* ---------------------- GRU DATA COPY FUNCTIONS ---------------------------*/

/*
 * Copy a block of data using the GRU resources
 */
int gru_copy_gpa(unsigned long dest_gpa, unsigned long src_gpa,
                                unsigned int bytes)
{
        void *cb;
        void *dsr;
        int ret;

        STAT(copy_gpa);
        if (gru_get_cpu_resources(GRU_NUM_KERNEL_DSR_BYTES, &cb, &dsr))
                return MQE_BUG_NO_RESOURCES;
        gru_bcopy(cb, src_gpa, dest_gpa, gru_get_tri(dsr),
                  XTYPE_B, bytes, GRU_NUM_KERNEL_DSR_CL, IMA);
        ret = gru_wait(cb);
        gru_free_cpu_resources(cb, dsr);
        return ret;
}
EXPORT_SYMBOL_GPL(gru_copy_gpa);

/* ------------------- KERNEL QUICKTESTS RUN AT STARTUP ----------------*/
/*      Temp - will delete after we gain confidence in the GRU          */
static __cacheline_aligned unsigned long word0;
static __cacheline_aligned unsigned long word1;

static int quicktest(struct gru_state *gru)
{
        void *cb;
        void *ds;
        unsigned long *p;

        cb = get_gseg_base_address_cb(gru->gs_gru_base_vaddr, KERNEL_CTXNUM, 0);
        ds = get_gseg_base_address_ds(gru->gs_gru_base_vaddr, KERNEL_CTXNUM, 0);
        p = ds;
        word0 = MAGIC;

        gru_vload(cb, uv_gpa(&word0), 0, XTYPE_DW, 1, 1, IMA);
        if (gru_wait(cb) != CBS_IDLE)
                BUG();

        if (*(unsigned long *)ds != MAGIC)
                BUG();
        gru_vstore(cb, uv_gpa(&word1), 0, XTYPE_DW, 1, 1, IMA);
        if (gru_wait(cb) != CBS_IDLE)
                BUG();

        if (word0 != word1 || word0 != MAGIC) {
                printk
                    ("GRU quicktest err: gid %d, found 0x%lx, expected 0x%lx\n",
                     gru->gs_gid, word1, MAGIC);
                BUG();          /* ZZZ should not be fatal */
        }

        return 0;
}


int gru_kservices_init(struct gru_state *gru)
{
        struct gru_blade_state *bs;
        struct gru_context_configuration_handle *cch;
        unsigned long cbr_map, dsr_map;
        int err, num, cpus_possible;

        /*
         * Currently, resources are reserved ONLY on the second chiplet
         * on each blade. This leaves ALL resources on chiplet 0 available
         * for user code.
         */
        bs = gru->gs_blade;
        if (gru != &bs->bs_grus[1])
                return 0;

        cpus_possible = uv_blade_nr_possible_cpus(gru->gs_blade_id);

        num = GRU_NUM_KERNEL_CBR * cpus_possible;
        cbr_map = gru_reserve_cb_resources(gru, GRU_CB_COUNT_TO_AU(num), NULL);
        gru->gs_reserved_cbrs += num;

        num = GRU_NUM_KERNEL_DSR_BYTES * cpus_possible;
        dsr_map = gru_reserve_ds_resources(gru, GRU_DS_BYTES_TO_AU(num), NULL);
        gru->gs_reserved_dsr_bytes += num;

        gru->gs_active_contexts++;
        __set_bit(KERNEL_CTXNUM, &gru->gs_context_map);
        cch = get_cch(gru->gs_gru_base_vaddr, KERNEL_CTXNUM);

        bs->kernel_cb = get_gseg_base_address_cb(gru->gs_gru_base_vaddr,
                                        KERNEL_CTXNUM, 0);
        bs->kernel_dsr = get_gseg_base_address_ds(gru->gs_gru_base_vaddr,
                                        KERNEL_CTXNUM, 0);

        lock_cch_handle(cch);
        cch->tfm_fault_bit_enable = 0;
        cch->tlb_int_enable = 0;
        cch->tfm_done_bit_enable = 0;
        cch->unmap_enable = 1;
        err = cch_allocate(cch, 0, 0, cbr_map, dsr_map);
        if (err) {
                gru_dbg(grudev,
                        "Unable to allocate kernel CCH: gid %d, err %d\n",
                        gru->gs_gid, err);
                BUG();
        }
        if (cch_start(cch)) {
                gru_dbg(grudev, "Unable to start kernel CCH: gid %d, err %d\n",
                        gru->gs_gid, err);
                BUG();
        }
        unlock_cch_handle(cch);

        if (gru_options & GRU_QUICKLOOK)
                quicktest(gru);
        return 0;
}

void gru_kservices_exit(struct gru_state *gru)
{
        struct gru_context_configuration_handle *cch;
        struct gru_blade_state *bs;

        bs = gru->gs_blade;
        if (gru != &bs->bs_grus[1])
                return;

        cch = get_cch(gru->gs_gru_base_vaddr, KERNEL_CTXNUM);
        lock_cch_handle(cch);
        if (cch_interrupt_sync(cch))
                BUG();
        if (cch_deallocate(cch))
                BUG();
        unlock_cch_handle(cch);
}