root/drivers/hwtracing/intel_th/sth.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Intel(R) Trace Hub Software Trace Hub support
 *
 * Copyright (C) 2014-2015 Intel Corporation.
 */

#define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt

#include <linux/types.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/stm.h>

#include "intel_th.h"
#include "sth.h"

struct sth_device {
        void __iomem    *base;
        void __iomem    *channels;
        phys_addr_t     channels_phys;
        struct device   *dev;
        struct stm_data stm;
        unsigned int    sw_nmasters;
};

static struct intel_th_channel __iomem *
sth_channel(struct sth_device *sth, unsigned int master, unsigned int channel)
{
        struct intel_th_channel __iomem *sw_map = sth->channels;

        return &sw_map[(master - sth->stm.sw_start) * sth->stm.sw_nchannels +
                       channel];
}

static void sth_iowrite(void __iomem *dest, const unsigned char *payload,
                        unsigned int size)
{
        switch (size) {
#ifdef CONFIG_64BIT
        case 8:
                writeq_relaxed(*(u64 *)payload, dest);
                break;
#endif
        case 4:
                writel_relaxed(*(u32 *)payload, dest);
                break;
        case 2:
                writew_relaxed(*(u16 *)payload, dest);
                break;
        case 1:
                writeb_relaxed(*(u8 *)payload, dest);
                break;
        default:
                break;
        }
}

static ssize_t notrace sth_stm_packet(struct stm_data *stm_data,
                                      unsigned int master,
                                      unsigned int channel,
                                      unsigned int packet,
                                      unsigned int flags,
                                      unsigned int size,
                                      const unsigned char *payload)
{
        struct sth_device *sth = container_of(stm_data, struct sth_device, stm);
        struct intel_th_channel __iomem *out =
                sth_channel(sth, master, channel);
        unsigned long reg = REG_STH_TRIG;
        u64 __iomem *outp;

#ifndef CONFIG_64BIT
        if (size > 4)
                size = 4;
#endif

        size = rounddown_pow_of_two(size);

        switch (packet) {
        /* Global packets (GERR, XSYNC, TRIG) are sent with register writes */
        case STP_PACKET_GERR:
                reg += 4;
                fallthrough;

        case STP_PACKET_XSYNC:
                reg += 8;
                fallthrough;

        case STP_PACKET_TRIG:
                if (flags & STP_PACKET_TIMESTAMPED)
                        reg += 4;
                writeb_relaxed(*payload, sth->base + reg);
                break;

        case STP_PACKET_MERR:
                if (size > 4)
                        size = 4;

                sth_iowrite(&out->MERR, payload, size);
                break;

        case STP_PACKET_FLAG:
                if (flags & STP_PACKET_TIMESTAMPED)
                        outp = (u64 __iomem *)&out->FLAG_TS;
                else
                        outp = (u64 __iomem *)&out->FLAG;

                size = 0;
                writeb_relaxed(0, outp);
                break;

        case STP_PACKET_USER:
                if (flags & STP_PACKET_TIMESTAMPED)
                        outp = &out->USER_TS;
                else
                        outp = &out->USER;
                sth_iowrite(outp, payload, size);
                break;

        case STP_PACKET_DATA:
                outp = &out->Dn;

                if (flags & STP_PACKET_TIMESTAMPED)
                        outp += 2;
                if (flags & STP_PACKET_MARKED)
                        outp++;

                sth_iowrite(outp, payload, size);
                break;
        default:
                return -ENOTSUPP;
        }

        return size;
}

static phys_addr_t
sth_stm_mmio_addr(struct stm_data *stm_data, unsigned int master,
                  unsigned int channel, unsigned int nr_chans)
{
        struct sth_device *sth = container_of(stm_data, struct sth_device, stm);
        phys_addr_t addr;

        master -= sth->stm.sw_start;
        addr = sth->channels_phys + (master * sth->stm.sw_nchannels + channel) *
                sizeof(struct intel_th_channel);

        if (offset_in_page(addr) ||
            offset_in_page(nr_chans * sizeof(struct intel_th_channel)))
                return 0;

        return addr;
}

static int sth_stm_link(struct stm_data *stm_data, unsigned int master,
                         unsigned int channel)
{
        struct sth_device *sth = container_of(stm_data, struct sth_device, stm);

        return intel_th_set_output(to_intel_th_device(sth->dev), master);
}

static int intel_th_sw_init(struct sth_device *sth)
{
        u32 reg;

        reg = ioread32(sth->base + REG_STH_STHCAP1);
        sth->stm.sw_nchannels = reg & 0xff;

        reg = ioread32(sth->base + REG_STH_STHCAP0);
        sth->stm.sw_start = reg & 0xffff;
        sth->stm.sw_end = reg >> 16;

        sth->sw_nmasters = sth->stm.sw_end - sth->stm.sw_start;
        dev_dbg(sth->dev, "sw_start: %x sw_end: %x masters: %x nchannels: %x\n",
                sth->stm.sw_start, sth->stm.sw_end, sth->sw_nmasters,
                sth->stm.sw_nchannels);

        return 0;
}

static int intel_th_sth_probe(struct intel_th_device *thdev)
{
        struct device *dev = &thdev->dev;
        struct sth_device *sth;
        struct resource *res;
        void __iomem *base, *channels;
        int err;

        res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
        if (!res)
                return -ENODEV;

        base = devm_ioremap(dev, res->start, resource_size(res));
        if (!base)
                return -ENOMEM;

        res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 1);
        if (!res)
                return -ENODEV;

        channels = devm_ioremap(dev, res->start, resource_size(res));
        if (!channels)
                return -ENOMEM;

        sth = devm_kzalloc(dev, sizeof(*sth), GFP_KERNEL);
        if (!sth)
                return -ENOMEM;

        sth->dev = dev;
        sth->base = base;
        sth->channels = channels;
        sth->channels_phys = res->start;
        sth->stm.name = dev_name(dev);
        sth->stm.packet = sth_stm_packet;
        sth->stm.mmio_addr = sth_stm_mmio_addr;
        sth->stm.sw_mmiosz = sizeof(struct intel_th_channel);
        sth->stm.link = sth_stm_link;

        err = intel_th_sw_init(sth);
        if (err)
                return err;

        err = stm_register_device(dev, &sth->stm, THIS_MODULE);
        if (err) {
                dev_err(dev, "stm_register_device failed\n");
                return err;
        }

        dev_set_drvdata(dev, sth);

        return 0;
}

static void intel_th_sth_remove(struct intel_th_device *thdev)
{
        struct sth_device *sth = dev_get_drvdata(&thdev->dev);

        stm_unregister_device(&sth->stm);
}

static struct intel_th_driver intel_th_sth_driver = {
        .probe  = intel_th_sth_probe,
        .remove = intel_th_sth_remove,
        .driver = {
                .name   = "sth",
                .owner  = THIS_MODULE,
        },
};

module_driver(intel_th_sth_driver,
              intel_th_driver_register,
              intel_th_driver_unregister);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Intel(R) Trace Hub Software Trace Hub driver");
MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@intel.com>");