/*
 * Copyright (C) 2016 Red Hat
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors:
 * Rob Clark <robdclark@gmail.com>
 */

#define DEBUG /* for pr_debug() */

#include <linux/stdarg.h>

#include <linux/io.h>
#include <linux/moduleparam.h>
#include <linux/seq_file.h>
#include <linux/slab.h>

#include <drm/drm.h>
#include <drm/drm_drv.h>
#include <drm/drm_print.h>

/*
 * __drm_debug: Enable debug output.
 * Bitmask of DRM_UT_x. See include/drm/drm_print.h for details.
 */
unsigned int __drm_debug;
EXPORT_SYMBOL(__drm_debug);

MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug category.\n"
"\t\tBit 0 (0x01)  will enable CORE messages (drm core code)\n"
"\t\tBit 1 (0x02)  will enable DRIVER messages (drm controller code)\n"
"\t\tBit 2 (0x04)  will enable KMS messages (modesetting code)\n"
"\t\tBit 3 (0x08)  will enable PRIME messages (prime code)\n"
"\t\tBit 4 (0x10)  will enable ATOMIC messages (atomic code)\n"
"\t\tBit 5 (0x20)  will enable VBL messages (vblank code)\n"
"\t\tBit 7 (0x80)  will enable LEASE messages (leasing code)\n"
"\t\tBit 8 (0x100) will enable DP messages (displayport code)");
module_param_named(debug, __drm_debug, int, 0600);

void __drm_puts_coredump(struct drm_printer *p, const char *str)
{
        struct drm_print_iterator *iterator = p->arg;
        ssize_t len;

        if (!iterator->remain)
                return;

        if (iterator->offset < iterator->start) {
                ssize_t copy;

                len = strlen(str);

                if (iterator->offset + len <= iterator->start) {
                        iterator->offset += len;
                        return;
                }

                copy = len - (iterator->start - iterator->offset);

                if (copy > iterator->remain)
                        copy = iterator->remain;

                /* Copy out the bit of the string that we need */
                memcpy(iterator->data,
                        str + (iterator->start - iterator->offset), copy);

                iterator->offset = iterator->start + copy;
                iterator->remain -= copy;
        } else {
                ssize_t pos = iterator->offset - iterator->start;

                len = min_t(ssize_t, strlen(str), iterator->remain);

                memcpy(iterator->data + pos, str, len);

                iterator->offset += len;
                iterator->remain -= len;
        }
}
EXPORT_SYMBOL(__drm_puts_coredump);

void __drm_printfn_coredump(struct drm_printer *p, struct va_format *vaf)
{
        struct drm_print_iterator *iterator = p->arg;
        size_t len;
        char *buf;

        if (!iterator->remain)
                return;

        /* Figure out how big the string will be */
        len = snprintf(NULL, 0, "%pV", vaf);

        /* This is the easiest path, we've already advanced beyond the offset */
        if (iterator->offset + len <= iterator->start) {
                iterator->offset += len;
                return;
        }

        /* Then check if we can directly copy into the target buffer */
        if ((iterator->offset >= iterator->start) && (len < iterator->remain)) {
                ssize_t pos = iterator->offset - iterator->start;

                snprintf(((char *) iterator->data) + pos,
                        iterator->remain, "%pV", vaf);

                iterator->offset += len;
                iterator->remain -= len;

                return;
        }

        /*
         * Finally, hit the slow path and make a temporary string to copy over
         * using _drm_puts_coredump
         */
        buf = kmalloc(len + 1, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);
        if (!buf)
                return;

        snprintf(buf, len + 1, "%pV", vaf);
        __drm_puts_coredump(p, (const char *) buf);

        kfree(buf);
}
EXPORT_SYMBOL(__drm_printfn_coredump);

void __drm_puts_seq_file(struct drm_printer *p, const char *str)
{
        seq_puts(p->arg, str);
}
EXPORT_SYMBOL(__drm_puts_seq_file);

void __drm_printfn_seq_file(struct drm_printer *p, struct va_format *vaf)
{
        seq_printf(p->arg, "%pV", vaf);
}
EXPORT_SYMBOL(__drm_printfn_seq_file);

void __drm_printfn_info(struct drm_printer *p, struct va_format *vaf)
{
        dev_info(p->arg, "[" DRM_NAME "] %pV", vaf);
}
EXPORT_SYMBOL(__drm_printfn_info);

void __drm_printfn_debug(struct drm_printer *p, struct va_format *vaf)
{
        pr_debug("%s %pV", p->prefix, vaf);
}
EXPORT_SYMBOL(__drm_printfn_debug);

void __drm_printfn_err(struct drm_printer *p, struct va_format *vaf)
{
        pr_err("*ERROR* %s %pV", p->prefix, vaf);
}
EXPORT_SYMBOL(__drm_printfn_err);

/**
 * drm_puts - print a const string to a &drm_printer stream
 * @p: the &drm printer
 * @str: const string
 *
 * Allow &drm_printer types that have a constant string
 * option to use it.
 */
void drm_puts(struct drm_printer *p, const char *str)
{
        if (p->puts)
                p->puts(p, str);
        else
                drm_printf(p, "%s", str);
}
EXPORT_SYMBOL(drm_puts);

/**
 * drm_printf - print to a &drm_printer stream
 * @p: the &drm_printer
 * @f: format string
 */
void drm_printf(struct drm_printer *p, const char *f, ...)
{
        va_list args;

        va_start(args, f);
        drm_vprintf(p, f, &args);
        va_end(args);
}
EXPORT_SYMBOL(drm_printf);

/**
 * drm_print_bits - print bits to a &drm_printer stream
 *
 * Print bits (in flag fields for example) in human readable form.
 *
 * @p: the &drm_printer
 * @value: field value.
 * @bits: Array with bit names.
 * @nbits: Size of bit names array.
 */
void drm_print_bits(struct drm_printer *p, unsigned long value,
                    const char * const bits[], unsigned int nbits)
{
        bool first = true;
        unsigned int i;

        if (WARN_ON_ONCE(nbits > BITS_PER_TYPE(value)))
                nbits = BITS_PER_TYPE(value);

        for_each_set_bit(i, &value, nbits) {
                if (WARN_ON_ONCE(!bits[i]))
                        continue;
                drm_printf(p, "%s%s", first ? "" : ",",
                           bits[i]);
                first = false;
        }
        if (first)
                drm_printf(p, "(none)");
}
EXPORT_SYMBOL(drm_print_bits);

void drm_dev_printk(const struct device *dev, const char *level,
                    const char *format, ...)
{
        struct va_format vaf;
        va_list args;

        va_start(args, format);
        vaf.fmt = format;
        vaf.va = &args;

        if (dev)
                dev_printk(level, dev, "[" DRM_NAME ":%ps] %pV",
                           __builtin_return_address(0), &vaf);
        else
                printk("%s" "[" DRM_NAME ":%ps] %pV",
                       level, __builtin_return_address(0), &vaf);

        va_end(args);
}
EXPORT_SYMBOL(drm_dev_printk);

void drm_dev_dbg(const struct device *dev, enum drm_debug_category category,
                 const char *format, ...)
{
        struct va_format vaf;
        va_list args;

        if (!drm_debug_enabled(category))
                return;

        va_start(args, format);
        vaf.fmt = format;
        vaf.va = &args;

        if (dev)
                dev_printk(KERN_DEBUG, dev, "[" DRM_NAME ":%ps] %pV",
                           __builtin_return_address(0), &vaf);
        else
                printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV",
                       __builtin_return_address(0), &vaf);

        va_end(args);
}
EXPORT_SYMBOL(drm_dev_dbg);

void __drm_dbg(enum drm_debug_category category, const char *format, ...)
{
        struct va_format vaf;
        va_list args;

        if (!drm_debug_enabled(category))
                return;

        va_start(args, format);
        vaf.fmt = format;
        vaf.va = &args;

        printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV",
               __builtin_return_address(0), &vaf);

        va_end(args);
}
EXPORT_SYMBOL(__drm_dbg);

void __drm_err(const char *format, ...)
{
        struct va_format vaf;
        va_list args;

        va_start(args, format);
        vaf.fmt = format;
        vaf.va = &args;

        printk(KERN_ERR "[" DRM_NAME ":%ps] *ERROR* %pV",
               __builtin_return_address(0), &vaf);

        va_end(args);
}
EXPORT_SYMBOL(__drm_err);

/**
 * drm_print_regset32 - print the contents of registers to a
 * &drm_printer stream.
 *
 * @p: the &drm printer
 * @regset: the list of registers to print.
 *
 * Often in driver debug, it's useful to be able to either capture the
 * contents of registers in the steady state using debugfs or at
 * specific points during operation.  This lets the driver have a
 * single list of registers for both.
 */
void drm_print_regset32(struct drm_printer *p, struct debugfs_regset32 *regset)
{
        int namelen = 0;
        int i;

        for (i = 0; i < regset->nregs; i++)
                namelen = max(namelen, (int)strlen(regset->regs[i].name));

        for (i = 0; i < regset->nregs; i++) {
                drm_printf(p, "%*s = 0x%08x\n",
                           namelen, regset->regs[i].name,
                           readl(regset->base + regset->regs[i].offset));
        }
}
EXPORT_SYMBOL(drm_print_regset32);