device/hypertransport.c: Remove dead assignment

[coreboot.git] / src / device / hypertransport.c

/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2003-2004 Linux Networx
 * (Written by Eric Biederman <ebiederman@lnxi.com> for Linux Networx)
 * Copyright (C) 2004 David Hendricks <sc@flagen.com>
 * Copyright (C) 2004 Li-Ta Lo <ollie@lanl.gov>
 * Copyright (C) 2005-2006 Tyan
 * (Written by Yinghai Lu <yhlu@tyan.com> for Tyan)
 * Copyright (C) 2005-2006 Stefan Reinauer <stepan@openbios.org>
 * Copyright (C) 2015 Timothy Pearson <tpearson@raptorengineeringinc.com>, Raptor Engineering
 *
 * 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; version 2 of the License.
 *
 * 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.
 */

#include <console/console.h>
#include <device/device.h>
#include <device/path.h>
#include <device/pci.h>
#include <device/pci_ops.h>
#include <device/pci_ids.h>
#include <device/hypertransport.h>

struct ht_link {
        struct device *dev;
        unsigned pos;
        unsigned char ctrl_off, config_off, freq_off, freq_cap_off;
};

static struct device *ht_scan_get_devs(struct device **old_devices)
{
        struct device *first, *last;

        first = *old_devices;
        last = first;

        /*
         * Extract the chain of devices to (first through last) for the next
         * hypertransport device.
         */
        while (last && last->sibling &&
               (last->sibling->path.type == DEVICE_PATH_PCI) &&
               (last->sibling->path.pci.devfn > last->path.pci.devfn))
        {
                last = last->sibling;
        }

        if (first) {
                struct device *child;

                /* Unlink the chain from the list of old devices. */
                *old_devices = last->sibling;
                last->sibling = 0;

                /* Now add the device to the list of devices on the bus. */
                /* Find the last child of our parent. */
                for (child = first->bus->children; child && child->sibling;)
                        child = child->sibling;

                /* Place the chain on the list of children of their parent. */
                if (child)
                        child->sibling = first;
                else
                        first->bus->children = first;
        }
        return first;
}

static int ht_setup_link(struct ht_link *prev, struct device *dev, unsigned pos)
{
        struct ht_link cur[1];
        int linkb_to_host;

        /* Set the hypertransport link width and frequency. */

        /*
         * See which side of the device our previous write to set the unitid
         * came from.
         */
        cur->dev = dev;
        cur->pos = pos;
        linkb_to_host =
          (pci_read_config16(cur->dev, cur->pos + PCI_CAP_FLAGS) >> 10) & 1;

        if (!linkb_to_host) {
                cur->ctrl_off     = PCI_HT_CAP_SLAVE_CTRL0;
                cur->config_off   = PCI_HT_CAP_SLAVE_WIDTH0;
                cur->freq_off     = PCI_HT_CAP_SLAVE_FREQ0;
                cur->freq_cap_off = PCI_HT_CAP_SLAVE_FREQ_CAP0;
        } else {
                cur->ctrl_off     = PCI_HT_CAP_SLAVE_CTRL1;
                cur->config_off   = PCI_HT_CAP_SLAVE_WIDTH1;
                cur->freq_off     = PCI_HT_CAP_SLAVE_FREQ1;
                cur->freq_cap_off = PCI_HT_CAP_SLAVE_FREQ_CAP1;
        }

        /*
         * Remember the current link as the previous link, but look at the
         * other offsets.
         */
        prev->dev = cur->dev;
        prev->pos = cur->pos;
        if (cur->ctrl_off == PCI_HT_CAP_SLAVE_CTRL0) {
                prev->ctrl_off     = PCI_HT_CAP_SLAVE_CTRL1;
                prev->config_off   = PCI_HT_CAP_SLAVE_WIDTH1;
                prev->freq_off     = PCI_HT_CAP_SLAVE_FREQ1;
                prev->freq_cap_off = PCI_HT_CAP_SLAVE_FREQ_CAP1;
        } else {
                prev->ctrl_off     = PCI_HT_CAP_SLAVE_CTRL0;
                prev->config_off   = PCI_HT_CAP_SLAVE_WIDTH0;
                prev->freq_off     = PCI_HT_CAP_SLAVE_FREQ0;
                prev->freq_cap_off = PCI_HT_CAP_SLAVE_FREQ_CAP0;
        }

        return 0;
}

static unsigned ht_lookup_slave_capability(struct device *dev)
{
        unsigned pos;

        pos = 0;
        do {
                pos = pci_find_next_capability(dev, PCI_CAP_ID_HT, pos);
                if (pos) {
                        u16 flags;
                        flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);
                        printk(BIOS_SPEW, "flags: 0x%04x\n", flags);
                        if ((flags >> 13) == 0) {
                                /* Entry is a slave secondary, success... */
                                break;
                        }
                }
        } while (pos);

        return pos;
}

static void ht_collapse_early_enumeration(struct bus *bus,
                                          unsigned offset_unitid)
{
        unsigned int devfn;
        struct ht_link prev;
        u16 ctrl;

        /* Initialize the hypertransport enumeration state. */
        prev.dev = bus->dev;
        prev.pos = bus->cap;
        prev.ctrl_off     = PCI_HT_CAP_HOST_CTRL;
        prev.config_off   = PCI_HT_CAP_HOST_WIDTH;
        prev.freq_off     = PCI_HT_CAP_HOST_FREQ;
        prev.freq_cap_off = PCI_HT_CAP_HOST_FREQ_CAP;

        /* Wait until the link initialization is complete. */
        do {
                ctrl = pci_read_config16(prev.dev, prev.pos + prev.ctrl_off);

                /* Is this the end of the hypertransport chain? */
                if (ctrl & (1 << 6))
                        return;

                /* Has the link failed? */
                if (ctrl & (1 << 4)) {
                        /*
                         * Either the link has failed, or we have a CRC error.
                         * Sometimes this can happen due to link retrain, so
                         * lets knock it down and see if its transient.
                         */
                        ctrl |= ((1 << 4) | (1 << 8)); /* Link fail + CRC */
                        pci_write_config16(prev.dev, prev.pos + prev.ctrl_off,
                                           ctrl);
                        ctrl = pci_read_config16(prev.dev,
                                                 prev.pos + prev.ctrl_off);
                        if (ctrl & ((1 << 4) | (1 << 8))) {
                                printk(BIOS_ALERT, "Detected error on "
                                       "Hypertransport link\n");
                                return;
                        }
                }
        } while ((ctrl & (1 << 5)) == 0);

        /* Actually, only for one HT device HT chain, and unitid is 0. */
#if !CONFIG_HT_CHAIN_UNITID_BASE
        if (offset_unitid)
                return;
#endif

        /* Check if is already collapsed. */
        if ((!offset_unitid) || (offset_unitid
            && (!((CONFIG_HT_CHAIN_END_UNITID_BASE == 0)
            && (CONFIG_HT_CHAIN_END_UNITID_BASE
            < CONFIG_HT_CHAIN_UNITID_BASE))))) {

                struct device dummy;
                u32 id;

                dummy.bus = bus;
                dummy.path.type = DEVICE_PATH_PCI;
                dummy.path.pci.devfn = PCI_DEVFN(0, 0);

                id = pci_read_config32(&dummy, PCI_VENDOR_ID);
                if (!((id == 0xffffffff) || (id == 0x00000000)
                    || (id == 0x0000ffff) || (id == 0xffff0000))) {
                        return;
                }
        }

        /* Spin through the devices and collapse any early HT enumeration. */
        for (devfn = PCI_DEVFN(1, 0); devfn <= 0xff; devfn += 8) {
                struct device dummy;
                u32 id;
                unsigned pos, flags;

                dummy.bus = bus;
                dummy.path.type = DEVICE_PATH_PCI;
                dummy.path.pci.devfn = devfn;

                id = pci_read_config32(&dummy, PCI_VENDOR_ID);
                if ((id == 0xffffffff) || (id == 0x00000000)
                    || (id == 0x0000ffff) || (id == 0xffff0000)) {
                        continue;
                }

                dummy.vendor = id & 0xffff;
                dummy.device = (id >> 16) & 0xffff;
                dummy.hdr_type = pci_read_config8(&dummy, PCI_HEADER_TYPE);

                pos = ht_lookup_slave_capability(&dummy);
                if (!pos)
                        continue;

                /* Clear the unitid. */
                flags = pci_read_config16(&dummy, pos + PCI_CAP_FLAGS);
                flags &= ~0x1f;
                pci_write_config16(&dummy, pos + PCI_CAP_FLAGS, flags);
                printk(BIOS_SPEW, "Collapsing %s [%04x/%04x]\n",
                       dev_path(&dummy), dummy.vendor, dummy.device);
        }
}

static unsigned int do_hypertransport_scan_chain(struct bus *bus, unsigned min_devfn,
                                       unsigned max_devfn,
                                       unsigned *ht_unitid_base,
                                       unsigned offset_unitid)
{
        /*
         * Even CONFIG_HT_CHAIN_UNITID_BASE == 0, we still can go through this
         * function, because of end_of_chain check. Also, we need it to
         * optimize link.
         */
        unsigned int next_unitid, last_unitid, min_unitid, max_unitid;
        struct device *old_devices, *dev, *func, *last_func = NULL;
        struct ht_link prev;
        int ht_dev_num = 0;

        printk(BIOS_SPEW, "%s for bus %02x\n", __func__, bus->secondary);

        min_unitid = (offset_unitid) ? CONFIG_HT_CHAIN_UNITID_BASE : 1;

#if CONFIG_HT_CHAIN_END_UNITID_BASE != 0x20
        /*
         * Let's record the device of last HT device, so we can set the unitid
         * to CONFIG_HT_CHAIN_END_UNITID_BASE.
         */
        unsigned int real_last_unitid = 0, end_used = 0;
        u8 real_last_pos = 0;
        struct device *real_last_dev = NULL;
#endif

        /* Restore the hypertransport chain to it's uninitialized state. */
        ht_collapse_early_enumeration(bus, offset_unitid);

        /* See which static device nodes I have. */
        old_devices = bus->children;
        bus->children = 0;

        /* Initialize the hypertransport enumeration state. */
        prev.dev = bus->dev;
        prev.pos = bus->cap;

        prev.ctrl_off     = PCI_HT_CAP_HOST_CTRL;
        prev.config_off   = PCI_HT_CAP_HOST_WIDTH;
        prev.freq_off     = PCI_HT_CAP_HOST_FREQ;
        prev.freq_cap_off = PCI_HT_CAP_HOST_FREQ_CAP;

        /* If present, assign unitid to a hypertransport chain. */
        max_unitid = next_unitid = min_unitid;
        do {
                u8 pos;
                u16 flags, ctrl;
                unsigned int count, static_count;

                last_unitid = next_unitid;

                /* Wait until the link initialization is complete. */
                do {
                        ctrl = pci_read_config16(prev.dev,
                                                 prev.pos + prev.ctrl_off);

                        /* End of chain? */
                        if (ctrl & (1 << 6))
                                goto end_of_chain;

                        if (ctrl & ((1 << 4) | (1 << 8))) {
                                /*
                                 * Either the link has failed, or we have a CRC
                                 * error. Sometimes this can happen due to link
                                 * retrain, so lets knock it down and see if
                                 * it's transient.
                                 */
                                ctrl |= ((1 << 4) | (1 <<8)); // Link fail + CRC
                                pci_write_config16(prev.dev,
                                        prev.pos + prev.ctrl_off, ctrl);
                                ctrl = pci_read_config16(prev.dev,
                                                prev.pos + prev.ctrl_off);
                                if (ctrl & ((1 << 4) | (1 << 8))) {
                                        printk(BIOS_ALERT, "Detected error on "
                                               "hypertransport link\n");
                                        goto end_of_chain;
                                }
                        }
                } while ((ctrl & (1 << 5)) == 0);


                /* Get and setup the device_structure. */
                dev = ht_scan_get_devs(&old_devices);

                /* See if a device is present and setup the device structure. */
                dev = pci_probe_dev(dev, bus, 0);
                if (!dev || !dev->enabled)
                        break;

                /* Find the hypertransport link capability. */
                pos = ht_lookup_slave_capability(dev);
                if (pos == 0) {
                        printk(BIOS_ERR, "%s Hypertransport link capability "
                               "not found", dev_path(dev));
                        break;
                }

                /* Update the unitid of the current device. */
                flags = pci_read_config16(dev, pos + PCI_CAP_FLAGS);

                /*
                 * If the device has a unitid set and is at devfn 0 we are
                 * done. This can happen with shadow hypertransport devices,
                 * or if we have reached the bottom of a HT device chain.
                 */
                if (flags & 0x1f)
                        break;

                flags &= ~0x1f; /* Mask out base Unit ID. */

                count = (flags >> 5) & 0x1f; /* Het unit count. */

#if CONFIG_HT_CHAIN_END_UNITID_BASE != 0x20
                if (offset_unitid) {
                        /* max_devfn will be (0x17<<3)|7 or (0x1f<<3)|7. */
                        if (next_unitid > (max_devfn >> 3)) {
                                if (!end_used) {
                                        next_unitid =
                                          CONFIG_HT_CHAIN_END_UNITID_BASE;
                                        end_used = 1;
                                } else {
                                        goto end_of_chain;
                                }
                        }
                }
#endif

                flags |= next_unitid & 0x1f;
                pci_write_config16(dev, pos + PCI_CAP_FLAGS, flags);

                /* Update the unitid in the device structure. */
                static_count = 1;
                for (func = dev; func; func = func->sibling) {
                        func->path.pci.devfn += (next_unitid << 3);
                        static_count = (func->path.pci.devfn >> 3)
                                        - (dev->path.pci.devfn >> 3) + 1;
                        last_func = func;
                }

                /* Compute the number of unitids consumed. */
                printk(BIOS_SPEW, "%s count: %04x static_count: %04x\n",
                       dev_path(dev), count, static_count);
                if (count < static_count)
                        count = static_count;

                /* Update the unitid of the next device. */
                ht_unitid_base[ht_dev_num] = next_unitid;
                ht_dev_num++;

#if CONFIG_HT_CHAIN_END_UNITID_BASE != 0x20
                if (offset_unitid) {
                        real_last_pos = pos;
                        real_last_unitid = next_unitid;
                        real_last_dev = dev;
                }
#endif
                next_unitid += count;
                if (next_unitid > max_unitid)
                        max_unitid = next_unitid;

                /* Setup the hypertransport link. */
                bus->reset_needed |= ht_setup_link(&prev, dev, pos);

                printk(BIOS_DEBUG, "%s [%04x/%04x] %s next_unitid: %04x\n",
                       dev_path(dev), dev->vendor, dev->device,
                       (dev->enabled? "enabled" : "disabled"), next_unitid);

        } while (last_unitid != next_unitid);

end_of_chain:

#if CONFIG_HT_CHAIN_END_UNITID_BASE != 0x20
        if (offset_unitid && (ht_dev_num > 1)
            && (real_last_unitid != CONFIG_HT_CHAIN_END_UNITID_BASE)
            && !end_used) {
                u16 flags;
                flags = pci_read_config16(real_last_dev,
                                          real_last_pos + PCI_CAP_FLAGS);
                flags &= ~0x1f;
                flags |= CONFIG_HT_CHAIN_END_UNITID_BASE & 0x1f;
                pci_write_config16(real_last_dev,
                                   real_last_pos + PCI_CAP_FLAGS, flags);

                for (func = real_last_dev; func; func = func->sibling) {
                        func->path.pci.devfn -= ((real_last_unitid
                                - CONFIG_HT_CHAIN_END_UNITID_BASE) << 3);
                        last_func = func;
                }

                /* Update last one. */
                ht_unitid_base[ht_dev_num-1] = CONFIG_HT_CHAIN_END_UNITID_BASE;

                printk(BIOS_DEBUG, " unitid: %04x --> %04x\n",
                       real_last_unitid, CONFIG_HT_CHAIN_END_UNITID_BASE);
        }
#endif
        next_unitid = max_unitid;

        if (next_unitid > 0x20)
                next_unitid = 0x20;

        if ((bus->secondary == 0) && (next_unitid > 0x18))
                next_unitid = 0x18; /* Avoid K8 on bus 0. */

        /*
         * Die if any leftover static devices are are found. There's probably
         * a problem in devicetree.cb.
         */
        if (old_devices) {
                struct device *left;
                for (left = old_devices; left; left = left->sibling)
                        printk(BIOS_DEBUG, "%s\n", dev_path(left));

                printk(BIOS_ERR, "HT: Leftover static devices. "
                       "Check your devicetree.cb\n");

                /*
                 * Put back the leftover static device, and let pci_scan_bus()
                 * disable it.
                 */
                if (last_func && !last_func->sibling)
                        last_func->sibling = old_devices;
        }

        return next_unitid;
}

unsigned int hypertransport_scan_chain(struct bus *bus)
{
        int i;
        unsigned int max_devfn;
        u32 ht_unitid_base[4];

        for (i = 0; i < 4; i++)
                ht_unitid_base[i] = 0x20;

        if (bus->secondary == 0)
                max_devfn = (CONFIG_CDB << 3) - 1;
        else
                max_devfn = (0x20 << 3) - 1;

        unsigned int next_unitid = do_hypertransport_scan_chain(bus, 0, max_devfn,
                                         ht_unitid_base, offset_unit_id(bus->secondary == 0));

        bus->hcdn_reg = 0;
        for (i = 0; i < 4; i++)
                bus->hcdn_reg |= (ht_unitid_base[i] & 0xff) << (i*8);

        return next_unitid;
}

/**
 * Scan a PCI bridge and the buses behind the bridge.
 *
 * Determine the existence of buses behind the bridge. Set up the bridge
 * according to the result of the scan.
 *
 * This function is the default scan_bus() method for PCI bridge devices.
 *
 * @param bus TODO
 * @param min_devfn TODO
 * @param max_devfn TODO
 */
static void hypertransport_scan_chain_x(struct bus *bus,
        unsigned int min_devfn, unsigned int max_devfn)
{
        unsigned int ht_unitid_base[4];
        unsigned int offset_unitid = 1;

        unsigned int next_unitid = do_hypertransport_scan_chain(bus, min_devfn, max_devfn,
                                         ht_unitid_base, offset_unitid);

        /* Now that nothing is overlapping it is safe to scan the children. */
        pci_scan_bus(bus, 0x00, ((next_unitid - 1) << 3) | 7);
}

void ht_scan_bridge(struct device *dev)
{
        do_pci_scan_bridge(dev, hypertransport_scan_chain_x);
}

bool ht_is_non_coherent_link(struct bus *link)
{
        u32 link_type;
        do {
                link_type = pci_read_config32(link->dev, link->cap + 0x18);
        } while (link_type & ConnectionPending);

        if (!(link_type & LinkConnected))
                return false;

        do {
                link_type = pci_read_config32(link->dev, link->cap + 0x18);
        } while (!(link_type & InitComplete));

        return !!(link_type & NonCoherent);
}

/** Default device operations for hypertransport bridges */
static struct pci_operations ht_bus_ops_pci = {
        .set_subsystem = 0,
};

struct device_operations default_ht_ops_bus = {
        .read_resources   = pci_bus_read_resources,
        .set_resources    = pci_dev_set_resources,
        .enable_resources = pci_bus_enable_resources,
        .init             = 0,
        .scan_bus         = ht_scan_bridge,
        .enable           = 0,
        .reset_bus        = pci_bus_reset,
        .ops_pci          = &ht_bus_ops_pci,
};