treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

[mirror_ubuntu-hirsute-kernel.git] / arch / powerpc / sysdev / xive / spapr.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright 2016,2017 IBM Corporation.
 */

#define pr_fmt(fmt) "xive: " fmt

#include <linux/types.h>
#include <linux/irq.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/cpumask.h>
#include <linux/mm.h>
#include <linux/delay.h>

#include <asm/prom.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/irq.h>
#include <asm/errno.h>
#include <asm/xive.h>
#include <asm/xive-regs.h>
#include <asm/hvcall.h>

#include "xive-internal.h"

static u32 xive_queue_shift;

struct xive_irq_bitmap {
        unsigned long           *bitmap;
        unsigned int            base;
        unsigned int            count;
        spinlock_t              lock;
        struct list_head        list;
};

static LIST_HEAD(xive_irq_bitmaps);

static int xive_irq_bitmap_add(int base, int count)
{
        struct xive_irq_bitmap *xibm;

        xibm = kzalloc(sizeof(*xibm), GFP_ATOMIC);
        if (!xibm)
                return -ENOMEM;

        spin_lock_init(&xibm->lock);
        xibm->base = base;
        xibm->count = count;
        xibm->bitmap = kzalloc(xibm->count, GFP_KERNEL);
        list_add(&xibm->list, &xive_irq_bitmaps);

        pr_info("Using IRQ range [%x-%x]", xibm->base,
                xibm->base + xibm->count - 1);
        return 0;
}

static int __xive_irq_bitmap_alloc(struct xive_irq_bitmap *xibm)
{
        int irq;

        irq = find_first_zero_bit(xibm->bitmap, xibm->count);
        if (irq != xibm->count) {
                set_bit(irq, xibm->bitmap);
                irq += xibm->base;
        } else {
                irq = -ENOMEM;
        }

        return irq;
}

static int xive_irq_bitmap_alloc(void)
{
        struct xive_irq_bitmap *xibm;
        unsigned long flags;
        int irq = -ENOENT;

        list_for_each_entry(xibm, &xive_irq_bitmaps, list) {
                spin_lock_irqsave(&xibm->lock, flags);
                irq = __xive_irq_bitmap_alloc(xibm);
                spin_unlock_irqrestore(&xibm->lock, flags);
                if (irq >= 0)
                        break;
        }
        return irq;
}

static void xive_irq_bitmap_free(int irq)
{
        unsigned long flags;
        struct xive_irq_bitmap *xibm;

        list_for_each_entry(xibm, &xive_irq_bitmaps, list) {
                if ((irq >= xibm->base) && (irq < xibm->base + xibm->count)) {
                        spin_lock_irqsave(&xibm->lock, flags);
                        clear_bit(irq - xibm->base, xibm->bitmap);
                        spin_unlock_irqrestore(&xibm->lock, flags);
                        break;
                }
        }
}


/* Based on the similar routines in RTAS */
static unsigned int plpar_busy_delay_time(long rc)
{
        unsigned int ms = 0;

        if (H_IS_LONG_BUSY(rc)) {
                ms = get_longbusy_msecs(rc);
        } else if (rc == H_BUSY) {
                ms = 10; /* seems appropriate for XIVE hcalls */
        }

        return ms;
}

static unsigned int plpar_busy_delay(int rc)
{
        unsigned int ms;

        ms = plpar_busy_delay_time(rc);
        if (ms)
                mdelay(ms);

        return ms;
}

/*
 * Note: this call has a partition wide scope and can take a while to
 * complete. If it returns H_LONG_BUSY_* it should be retried
 * periodically.
 */
static long plpar_int_reset(unsigned long flags)
{
        long rc;

        do {
                rc = plpar_hcall_norets(H_INT_RESET, flags);
        } while (plpar_busy_delay(rc));

        if (rc)
                pr_err("H_INT_RESET failed %ld\n", rc);

        return rc;
}

static long plpar_int_get_source_info(unsigned long flags,
                                      unsigned long lisn,
                                      unsigned long *src_flags,
                                      unsigned long *eoi_page,
                                      unsigned long *trig_page,
                                      unsigned long *esb_shift)
{
        unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
        long rc;

        do {
                rc = plpar_hcall(H_INT_GET_SOURCE_INFO, retbuf, flags, lisn);
        } while (plpar_busy_delay(rc));

        if (rc) {
                pr_err("H_INT_GET_SOURCE_INFO lisn=%ld failed %ld\n", lisn, rc);
                return rc;
        }

        *src_flags = retbuf[0];
        *eoi_page  = retbuf[1];
        *trig_page = retbuf[2];
        *esb_shift = retbuf[3];

        pr_devel("H_INT_GET_SOURCE_INFO flags=%lx eoi=%lx trig=%lx shift=%lx\n",
                retbuf[0], retbuf[1], retbuf[2], retbuf[3]);

        return 0;
}

#define XIVE_SRC_SET_EISN (1ull << (63 - 62))
#define XIVE_SRC_MASK     (1ull << (63 - 63)) /* unused */

static long plpar_int_set_source_config(unsigned long flags,
                                        unsigned long lisn,
                                        unsigned long target,
                                        unsigned long prio,
                                        unsigned long sw_irq)
{
        long rc;


        pr_devel("H_INT_SET_SOURCE_CONFIG flags=%lx lisn=%lx target=%lx prio=%lx sw_irq=%lx\n",
                flags, lisn, target, prio, sw_irq);


        do {
                rc = plpar_hcall_norets(H_INT_SET_SOURCE_CONFIG, flags, lisn,
                                        target, prio, sw_irq);
        } while (plpar_busy_delay(rc));

        if (rc) {
                pr_err("H_INT_SET_SOURCE_CONFIG lisn=%ld target=%lx prio=%lx failed %ld\n",
                       lisn, target, prio, rc);
                return rc;
        }

        return 0;
}

static long plpar_int_get_queue_info(unsigned long flags,
                                     unsigned long target,
                                     unsigned long priority,
                                     unsigned long *esn_page,
                                     unsigned long *esn_size)
{
        unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
        long rc;

        do {
                rc = plpar_hcall(H_INT_GET_QUEUE_INFO, retbuf, flags, target,
                                 priority);
        } while (plpar_busy_delay(rc));

        if (rc) {
                pr_err("H_INT_GET_QUEUE_INFO cpu=%ld prio=%ld failed %ld\n",
                       target, priority, rc);
                return rc;
        }

        *esn_page = retbuf[0];
        *esn_size = retbuf[1];

        pr_devel("H_INT_GET_QUEUE_INFO page=%lx size=%lx\n",
                retbuf[0], retbuf[1]);

        return 0;
}

#define XIVE_EQ_ALWAYS_NOTIFY (1ull << (63 - 63))

static long plpar_int_set_queue_config(unsigned long flags,
                                       unsigned long target,
                                       unsigned long priority,
                                       unsigned long qpage,
                                       unsigned long qsize)
{
        long rc;

        pr_devel("H_INT_SET_QUEUE_CONFIG flags=%lx target=%lx priority=%lx qpage=%lx qsize=%lx\n",
                flags,  target, priority, qpage, qsize);

        do {
                rc = plpar_hcall_norets(H_INT_SET_QUEUE_CONFIG, flags, target,
                                        priority, qpage, qsize);
        } while (plpar_busy_delay(rc));

        if (rc) {
                pr_err("H_INT_SET_QUEUE_CONFIG cpu=%ld prio=%ld qpage=%lx returned %ld\n",
                       target, priority, qpage, rc);
                return  rc;
        }

        return 0;
}

static long plpar_int_sync(unsigned long flags, unsigned long lisn)
{
        long rc;

        do {
                rc = plpar_hcall_norets(H_INT_SYNC, flags, lisn);
        } while (plpar_busy_delay(rc));

        if (rc) {
                pr_err("H_INT_SYNC lisn=%ld returned %ld\n", lisn, rc);
                return  rc;
        }

        return 0;
}

#define XIVE_ESB_FLAG_STORE (1ull << (63 - 63))

static long plpar_int_esb(unsigned long flags,
                          unsigned long lisn,
                          unsigned long offset,
                          unsigned long in_data,
                          unsigned long *out_data)
{
        unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
        long rc;

        pr_devel("H_INT_ESB flags=%lx lisn=%lx offset=%lx in=%lx\n",
                flags,  lisn, offset, in_data);

        do {
                rc = plpar_hcall(H_INT_ESB, retbuf, flags, lisn, offset,
                                 in_data);
        } while (plpar_busy_delay(rc));

        if (rc) {
                pr_err("H_INT_ESB lisn=%ld offset=%ld returned %ld\n",
                       lisn, offset, rc);
                return  rc;
        }

        *out_data = retbuf[0];

        return 0;
}

static u64 xive_spapr_esb_rw(u32 lisn, u32 offset, u64 data, bool write)
{
        unsigned long read_data;
        long rc;

        rc = plpar_int_esb(write ? XIVE_ESB_FLAG_STORE : 0,
                           lisn, offset, data, &read_data);
        if (rc)
                return -1;

        return write ? 0 : read_data;
}

#define XIVE_SRC_H_INT_ESB     (1ull << (63 - 60))
#define XIVE_SRC_LSI           (1ull << (63 - 61))
#define XIVE_SRC_TRIGGER       (1ull << (63 - 62))
#define XIVE_SRC_STORE_EOI     (1ull << (63 - 63))

static int xive_spapr_populate_irq_data(u32 hw_irq, struct xive_irq_data *data)
{
        long rc;
        unsigned long flags;
        unsigned long eoi_page;
        unsigned long trig_page;
        unsigned long esb_shift;

        memset(data, 0, sizeof(*data));

        rc = plpar_int_get_source_info(0, hw_irq, &flags, &eoi_page, &trig_page,
                                       &esb_shift);
        if (rc)
                return  -EINVAL;

        if (flags & XIVE_SRC_H_INT_ESB)
                data->flags  |= XIVE_IRQ_FLAG_H_INT_ESB;
        if (flags & XIVE_SRC_STORE_EOI)
                data->flags  |= XIVE_IRQ_FLAG_STORE_EOI;
        if (flags & XIVE_SRC_LSI)
                data->flags  |= XIVE_IRQ_FLAG_LSI;
        data->eoi_page  = eoi_page;
        data->esb_shift = esb_shift;
        data->trig_page = trig_page;

        /*
         * No chip-id for the sPAPR backend. This has an impact how we
         * pick a target. See xive_pick_irq_target().
         */
        data->src_chip = XIVE_INVALID_CHIP_ID;

        data->eoi_mmio = ioremap(data->eoi_page, 1u << data->esb_shift);
        if (!data->eoi_mmio) {
                pr_err("Failed to map EOI page for irq 0x%x\n", hw_irq);
                return -ENOMEM;
        }

        data->hw_irq = hw_irq;

        /* Full function page supports trigger */
        if (flags & XIVE_SRC_TRIGGER) {
                data->trig_mmio = data->eoi_mmio;
                return 0;
        }

        data->trig_mmio = ioremap(data->trig_page, 1u << data->esb_shift);
        if (!data->trig_mmio) {
                pr_err("Failed to map trigger page for irq 0x%x\n", hw_irq);
                return -ENOMEM;
        }
        return 0;
}

static int xive_spapr_configure_irq(u32 hw_irq, u32 target, u8 prio, u32 sw_irq)
{
        long rc;

        rc = plpar_int_set_source_config(XIVE_SRC_SET_EISN, hw_irq, target,
                                         prio, sw_irq);

        return rc == 0 ? 0 : -ENXIO;
}

/* This can be called multiple time to change a queue configuration */
static int xive_spapr_configure_queue(u32 target, struct xive_q *q, u8 prio,
                                   __be32 *qpage, u32 order)
{
        s64 rc = 0;
        unsigned long esn_page;
        unsigned long esn_size;
        u64 flags, qpage_phys;

        /* If there's an actual queue page, clean it */
        if (order) {
                if (WARN_ON(!qpage))
                        return -EINVAL;
                qpage_phys = __pa(qpage);
        } else {
                qpage_phys = 0;
        }

        /* Initialize the rest of the fields */
        q->msk = order ? ((1u << (order - 2)) - 1) : 0;
        q->idx = 0;
        q->toggle = 0;

        rc = plpar_int_get_queue_info(0, target, prio, &esn_page, &esn_size);
        if (rc) {
                pr_err("Error %lld getting queue info CPU %d prio %d\n", rc,
                       target, prio);
                rc = -EIO;
                goto fail;
        }

        /* TODO: add support for the notification page */
        q->eoi_phys = esn_page;

        /* Default is to always notify */
        flags = XIVE_EQ_ALWAYS_NOTIFY;

        /* Configure and enable the queue in HW */
        rc = plpar_int_set_queue_config(flags, target, prio, qpage_phys, order);
        if (rc) {
                pr_err("Error %lld setting queue for CPU %d prio %d\n", rc,
                       target, prio);
                rc = -EIO;
        } else {
                q->qpage = qpage;
        }
fail:
        return rc;
}

static int xive_spapr_setup_queue(unsigned int cpu, struct xive_cpu *xc,
                                  u8 prio)
{
        struct xive_q *q = &xc->queue[prio];
        __be32 *qpage;

        qpage = xive_queue_page_alloc(cpu, xive_queue_shift);
        if (IS_ERR(qpage))
                return PTR_ERR(qpage);

        return xive_spapr_configure_queue(get_hard_smp_processor_id(cpu),
                                          q, prio, qpage, xive_queue_shift);
}

static void xive_spapr_cleanup_queue(unsigned int cpu, struct xive_cpu *xc,
                                  u8 prio)
{
        struct xive_q *q = &xc->queue[prio];
        unsigned int alloc_order;
        long rc;
        int hw_cpu = get_hard_smp_processor_id(cpu);

        rc = plpar_int_set_queue_config(0, hw_cpu, prio, 0, 0);
        if (rc)
                pr_err("Error %ld setting queue for CPU %d prio %d\n", rc,
                       hw_cpu, prio);

        alloc_order = xive_alloc_order(xive_queue_shift);
        free_pages((unsigned long)q->qpage, alloc_order);
        q->qpage = NULL;
}

static bool xive_spapr_match(struct device_node *node)
{
        /* Ignore cascaded controllers for the moment */
        return 1;
}

#ifdef CONFIG_SMP
static int xive_spapr_get_ipi(unsigned int cpu, struct xive_cpu *xc)
{
        int irq = xive_irq_bitmap_alloc();

        if (irq < 0) {
                pr_err("Failed to allocate IPI on CPU %d\n", cpu);
                return -ENXIO;
        }

        xc->hw_ipi = irq;
        return 0;
}

static void xive_spapr_put_ipi(unsigned int cpu, struct xive_cpu *xc)
{
        if (!xc->hw_ipi)
                return;

        xive_irq_bitmap_free(xc->hw_ipi);
        xc->hw_ipi = 0;
}
#endif /* CONFIG_SMP */

static void xive_spapr_shutdown(void)
{
        plpar_int_reset(0);
}

/*
 * Perform an "ack" cycle on the current thread. Grab the pending
 * active priorities and update the CPPR to the most favored one.
 */
static void xive_spapr_update_pending(struct xive_cpu *xc)
{
        u8 nsr, cppr;
        u16 ack;

        /*
         * Perform the "Acknowledge O/S to Register" cycle.
         *
         * Let's speedup the access to the TIMA using the raw I/O
         * accessor as we don't need the synchronisation routine of
         * the higher level ones
         */
        ack = be16_to_cpu(__raw_readw(xive_tima + TM_SPC_ACK_OS_REG));

        /* Synchronize subsequent queue accesses */
        mb();

        /*
         * Grab the CPPR and the "NSR" field which indicates the source
         * of the interrupt (if any)
         */
        cppr = ack & 0xff;
        nsr = ack >> 8;

        if (nsr & TM_QW1_NSR_EO) {
                if (cppr == 0xff)
                        return;
                /* Mark the priority pending */
                xc->pending_prio |= 1 << cppr;

                /*
                 * A new interrupt should never have a CPPR less favored
                 * than our current one.
                 */
                if (cppr >= xc->cppr)
                        pr_err("CPU %d odd ack CPPR, got %d at %d\n",
                               smp_processor_id(), cppr, xc->cppr);

                /* Update our idea of what the CPPR is */
                xc->cppr = cppr;
        }
}

static void xive_spapr_eoi(u32 hw_irq)
{
        /* Not used */;
}

static void xive_spapr_setup_cpu(unsigned int cpu, struct xive_cpu *xc)
{
        /* Only some debug on the TIMA settings */
        pr_debug("(HW value: %08x %08x %08x)\n",
                 in_be32(xive_tima + TM_QW1_OS + TM_WORD0),
                 in_be32(xive_tima + TM_QW1_OS + TM_WORD1),
                 in_be32(xive_tima + TM_QW1_OS + TM_WORD2));
}

static void xive_spapr_teardown_cpu(unsigned int cpu, struct xive_cpu *xc)
{
        /* Nothing to do */;
}

static void xive_spapr_sync_source(u32 hw_irq)
{
        /* Specs are unclear on what this is doing */
        plpar_int_sync(0, hw_irq);
}

static const struct xive_ops xive_spapr_ops = {
        .populate_irq_data      = xive_spapr_populate_irq_data,
        .configure_irq          = xive_spapr_configure_irq,
        .setup_queue            = xive_spapr_setup_queue,
        .cleanup_queue          = xive_spapr_cleanup_queue,
        .match                  = xive_spapr_match,
        .shutdown               = xive_spapr_shutdown,
        .update_pending         = xive_spapr_update_pending,
        .eoi                    = xive_spapr_eoi,
        .setup_cpu              = xive_spapr_setup_cpu,
        .teardown_cpu           = xive_spapr_teardown_cpu,
        .sync_source            = xive_spapr_sync_source,
        .esb_rw                 = xive_spapr_esb_rw,
#ifdef CONFIG_SMP
        .get_ipi                = xive_spapr_get_ipi,
        .put_ipi                = xive_spapr_put_ipi,
#endif /* CONFIG_SMP */
        .name                   = "spapr",
};

/*
 * get max priority from "/ibm,plat-res-int-priorities"
 */
static bool xive_get_max_prio(u8 *max_prio)
{
        struct device_node *rootdn;
        const __be32 *reg;
        u32 len;
        int prio, found;

        rootdn = of_find_node_by_path("/");
        if (!rootdn) {
                pr_err("not root node found !\n");
                return false;
        }

        reg = of_get_property(rootdn, "ibm,plat-res-int-priorities", &len);
        if (!reg) {
                pr_err("Failed to read 'ibm,plat-res-int-priorities' property\n");
                return false;
        }

        if (len % (2 * sizeof(u32)) != 0) {
                pr_err("invalid 'ibm,plat-res-int-priorities' property\n");
                return false;
        }

        /* HW supports priorities in the range [0-7] and 0xFF is a
         * wildcard priority used to mask. We scan the ranges reserved
         * by the hypervisor to find the lowest priority we can use.
         */
        found = 0xFF;
        for (prio = 0; prio < 8; prio++) {
                int reserved = 0;
                int i;

                for (i = 0; i < len / (2 * sizeof(u32)); i++) {
                        int base  = be32_to_cpu(reg[2 * i]);
                        int range = be32_to_cpu(reg[2 * i + 1]);

                        if (prio >= base && prio < base + range)
                                reserved++;
                }

                if (!reserved)
                        found = prio;
        }

        if (found == 0xFF) {
                pr_err("no valid priority found in 'ibm,plat-res-int-priorities'\n");
                return false;
        }

        *max_prio = found;
        return true;
}

bool __init xive_spapr_init(void)
{
        struct device_node *np;
        struct resource r;
        void __iomem *tima;
        struct property *prop;
        u8 max_prio;
        u32 val;
        u32 len;
        const __be32 *reg;
        int i;

        if (xive_cmdline_disabled)
                return false;

        pr_devel("%s()\n", __func__);
        np = of_find_compatible_node(NULL, NULL, "ibm,power-ivpe");
        if (!np) {
                pr_devel("not found !\n");
                return false;
        }
        pr_devel("Found %s\n", np->full_name);

        /* Resource 1 is the OS ring TIMA */
        if (of_address_to_resource(np, 1, &r)) {
                pr_err("Failed to get thread mgmnt area resource\n");
                return false;
        }
        tima = ioremap(r.start, resource_size(&r));
        if (!tima) {
                pr_err("Failed to map thread mgmnt area\n");
                return false;
        }

        if (!xive_get_max_prio(&max_prio))
                return false;

        /* Feed the IRQ number allocator with the ranges given in the DT */
        reg = of_get_property(np, "ibm,xive-lisn-ranges", &len);
        if (!reg) {
                pr_err("Failed to read 'ibm,xive-lisn-ranges' property\n");
                return false;
        }

        if (len % (2 * sizeof(u32)) != 0) {
                pr_err("invalid 'ibm,xive-lisn-ranges' property\n");
                return false;
        }

        for (i = 0; i < len / (2 * sizeof(u32)); i++, reg += 2)
                xive_irq_bitmap_add(be32_to_cpu(reg[0]),
                                    be32_to_cpu(reg[1]));

        /* Iterate the EQ sizes and pick one */
        of_property_for_each_u32(np, "ibm,xive-eq-sizes", prop, reg, val) {
                xive_queue_shift = val;
                if (val == PAGE_SHIFT)
                        break;
        }

        /* Initialize XIVE core with our backend */
        if (!xive_core_init(&xive_spapr_ops, tima, TM_QW1_OS, max_prio))
                return false;

        pr_info("Using %dkB queues\n", 1 << (xive_queue_shift - 10));
        return true;
}