/*
 * Copyright © 2014 Intel Corporation
 *
 * 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 (including the next
 * paragraph) 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 AUTHORS OR COPYRIGHT HOLDERS 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:
 *    Daniel Vetter <daniel.vetter@ffwll.ch>
 *
 */

#include <linux/seq_buf.h>

#include <drm/drm_print.h>

#include "intel_de.h"
#include "intel_display_irq.h"
#include "intel_display_regs.h"
#include "intel_display_trace.h"
#include "intel_display_types.h"
#include "intel_fbc.h"
#include "intel_fifo_underrun.h"
#include "intel_pch_display.h"

/**
 * DOC: fifo underrun handling
 *
 * The i915 driver checks for display fifo underruns using the interrupt signals
 * provided by the hardware. This is enabled by default and fairly useful to
 * debug display issues, especially watermark settings.
 *
 * If an underrun is detected this is logged into dmesg. To avoid flooding logs
 * and occupying the cpu underrun interrupts are disabled after the first
 * occurrence until the next modeset on a given pipe.
 *
 * Note that underrun detection on gmch platforms is a bit more ugly since there
 * is no interrupt (despite that the signalling bit is in the PIPESTAT pipe
 * interrupt register). Also on some other platforms underrun interrupts are
 * shared, which means that if we detect an underrun we need to disable underrun
 * reporting on all pipes.
 *
 * The code also supports underrun detection on the PCH transcoder.
 */

#define UNDERRUN_DBG1_NUM_PLANES 6

static void log_underrun_dbg1(struct intel_display *display, enum pipe pipe,
                              unsigned long plane_mask, const char *info)
{
        DECLARE_SEQ_BUF(planes_desc, 32);
        unsigned int i;

        if (!plane_mask)
                return;

        for_each_set_bit(i, &plane_mask, UNDERRUN_DBG1_NUM_PLANES) {
                if (i == 0)
                        seq_buf_puts(&planes_desc, "[C]");
                else
                        seq_buf_printf(&planes_desc, "[%d]", i);
        }

        drm_err(display->drm, "Pipe %c FIFO underrun info: %s on planes: %s\n",
                pipe_name(pipe), info, seq_buf_str(&planes_desc));

        drm_WARN_ON(display->drm, seq_buf_has_overflowed(&planes_desc));
}

static void read_underrun_dbg1(struct intel_display *display, enum pipe pipe, bool log)
{
        u32 val = intel_de_read(display, UNDERRUN_DBG1(pipe));

        if (!val)
                return;

        intel_de_write(display, UNDERRUN_DBG1(pipe), val);

        if (!log)
                return;

        log_underrun_dbg1(display, pipe, REG_FIELD_GET(UNDERRUN_DBUF_BLOCK_NOT_VALID_MASK, val),
                          "DBUF block not valid");
        log_underrun_dbg1(display, pipe, REG_FIELD_GET(UNDERRUN_DDB_EMPTY_MASK, val),
                          "DDB empty");
        log_underrun_dbg1(display, pipe, REG_FIELD_GET(UNDERRUN_DBUF_NOT_FILLED_MASK, val),
                          "DBUF not completely filled");
        log_underrun_dbg1(display, pipe, REG_FIELD_GET(UNDERRUN_BELOW_WM0_MASK, val),
                          "DBUF below WM0");
}

static void read_underrun_dbg2(struct intel_display *display, enum pipe pipe, bool log)
{
        u32 val = intel_de_read(display, UNDERRUN_DBG2(pipe));

        if (!(val & UNDERRUN_FRAME_LINE_COUNTERS_FROZEN))
                return;

        intel_de_write(display, UNDERRUN_DBG2(pipe), UNDERRUN_FRAME_LINE_COUNTERS_FROZEN);

        if (log)
                drm_err(display->drm,
                        "Pipe %c FIFO underrun info: frame count: %u, line count: %u\n",
                        pipe_name(pipe),
                        REG_FIELD_GET(UNDERRUN_PIPE_FRAME_COUNT_MASK, val),
                        REG_FIELD_GET(UNDERRUN_LINE_COUNT_MASK, val));
}

static void read_underrun_dbg_pkgc(struct intel_display *display, bool log)
{
        u32 val = intel_de_read(display, GEN12_DCPR_STATUS_1);

        if (!(val & XE3P_UNDERRUN_PKGC))
                return;

        /*
         * Note: If there are multiple pipes enabled, only one of them will see
         * XE3P_UNDERRUN_PKGC set.
         */
        intel_de_write(display, GEN12_DCPR_STATUS_1, XE3P_UNDERRUN_PKGC);

        if (log)
                drm_err(display->drm,
                        "General FIFO underrun info: Package C-state blocking memory\n");
}

static void read_underrun_dbg_info(struct intel_display *display,
                                   enum pipe pipe,
                                   bool log)
{
        if (!HAS_UNDERRUN_DBG_INFO(display))
                return;

        read_underrun_dbg1(display, pipe, log);
        read_underrun_dbg2(display, pipe, log);
        intel_fbc_read_underrun_dbg_info(display, pipe, log);
        read_underrun_dbg_pkgc(display, log);
}

static bool ivb_can_enable_err_int(struct intel_display *display)
{
        struct intel_crtc *crtc;
        enum pipe pipe;

        lockdep_assert_held(&display->irq.lock);

        for_each_pipe(display, pipe) {
                crtc = intel_crtc_for_pipe(display, pipe);

                if (crtc->cpu_fifo_underrun_disabled)
                        return false;
        }

        return true;
}

static bool cpt_can_enable_serr_int(struct intel_display *display)
{
        enum pipe pipe;
        struct intel_crtc *crtc;

        lockdep_assert_held(&display->irq.lock);

        for_each_pipe(display, pipe) {
                crtc = intel_crtc_for_pipe(display, pipe);

                if (crtc->pch_fifo_underrun_disabled)
                        return false;
        }

        return true;
}

static void i9xx_check_fifo_underruns(struct intel_crtc *crtc)
{
        struct intel_display *display = to_intel_display(crtc);
        intel_reg_t reg = PIPESTAT(display, crtc->pipe);
        u32 enable_mask;

        lockdep_assert_held(&display->irq.lock);

        if ((intel_de_read(display, reg) & PIPE_FIFO_UNDERRUN_STATUS) == 0)
                return;

        enable_mask = i915_pipestat_enable_mask(display, crtc->pipe);
        intel_de_write(display, reg, enable_mask | PIPE_FIFO_UNDERRUN_STATUS);
        intel_de_posting_read(display, reg);

        trace_intel_cpu_fifo_underrun(display, crtc->pipe);
        drm_err(display->drm, "pipe %c underrun\n", pipe_name(crtc->pipe));
}

static void i9xx_set_fifo_underrun_reporting(struct intel_display *display,
                                             enum pipe pipe,
                                             bool enable, bool old)
{
        intel_reg_t reg = PIPESTAT(display, pipe);

        lockdep_assert_held(&display->irq.lock);

        if (enable) {
                u32 enable_mask = i915_pipestat_enable_mask(display, pipe);

                intel_de_write(display, reg,
                               enable_mask | PIPE_FIFO_UNDERRUN_STATUS);
                intel_de_posting_read(display, reg);
        } else {
                if (old && intel_de_read(display, reg) & PIPE_FIFO_UNDERRUN_STATUS)
                        drm_err(display->drm, "pipe %c underrun\n",
                                pipe_name(pipe));
        }
}

static void ilk_set_fifo_underrun_reporting(struct intel_display *display,
                                            enum pipe pipe, bool enable)
{
        u32 bit = (pipe == PIPE_A) ?
                DE_PIPEA_FIFO_UNDERRUN : DE_PIPEB_FIFO_UNDERRUN;

        if (enable)
                ilk_enable_display_irq(display, bit);
        else
                ilk_disable_display_irq(display, bit);
}

static void ivb_check_fifo_underruns(struct intel_crtc *crtc)
{
        struct intel_display *display = to_intel_display(crtc);
        enum pipe pipe = crtc->pipe;
        u32 err_int = intel_de_read(display, GEN7_ERR_INT);

        lockdep_assert_held(&display->irq.lock);

        if ((err_int & ERR_INT_FIFO_UNDERRUN(pipe)) == 0)
                return;

        intel_de_write(display, GEN7_ERR_INT, ERR_INT_FIFO_UNDERRUN(pipe));
        intel_de_posting_read(display, GEN7_ERR_INT);

        trace_intel_cpu_fifo_underrun(display, pipe);
        drm_err(display->drm, "fifo underrun on pipe %c\n", pipe_name(pipe));
}

static void ivb_set_fifo_underrun_reporting(struct intel_display *display,
                                            enum pipe pipe, bool enable,
                                            bool old)
{
        if (enable) {
                intel_de_write(display, GEN7_ERR_INT,
                               ERR_INT_FIFO_UNDERRUN(pipe));

                if (!ivb_can_enable_err_int(display))
                        return;

                ilk_enable_display_irq(display, DE_ERR_INT_IVB);
        } else {
                ilk_disable_display_irq(display, DE_ERR_INT_IVB);

                if (old &&
                    intel_de_read(display, GEN7_ERR_INT) & ERR_INT_FIFO_UNDERRUN(pipe)) {
                        drm_err(display->drm,
                                "uncleared fifo underrun on pipe %c\n",
                                pipe_name(pipe));
                }
        }
}

static void bdw_set_fifo_underrun_reporting(struct intel_display *display,
                                            enum pipe pipe, bool enable)
{
        if (enable)
                bdw_enable_pipe_irq(display, pipe, GEN8_PIPE_FIFO_UNDERRUN);
        else
                bdw_disable_pipe_irq(display, pipe, GEN8_PIPE_FIFO_UNDERRUN);
}

static void ibx_set_fifo_underrun_reporting(struct intel_display *display,
                                            enum pipe pch_transcoder,
                                            bool enable)
{
        u32 bit = (pch_transcoder == PIPE_A) ?
                SDE_TRANSA_FIFO_UNDER : SDE_TRANSB_FIFO_UNDER;

        if (enable)
                ibx_enable_display_interrupt(display, bit);
        else
                ibx_disable_display_interrupt(display, bit);
}

static void cpt_check_pch_fifo_underruns(struct intel_crtc *crtc)
{
        struct intel_display *display = to_intel_display(crtc);
        enum pipe pch_transcoder = crtc->pipe;
        u32 serr_int = intel_de_read(display, SERR_INT);

        lockdep_assert_held(&display->irq.lock);

        if ((serr_int & SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder)) == 0)
                return;

        intel_de_write(display, SERR_INT,
                       SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder));
        intel_de_posting_read(display, SERR_INT);

        trace_intel_pch_fifo_underrun(display, pch_transcoder);
        drm_err(display->drm, "pch fifo underrun on pch transcoder %c\n",
                pipe_name(pch_transcoder));
}

static void cpt_set_fifo_underrun_reporting(struct intel_display *display,
                                            enum pipe pch_transcoder,
                                            bool enable, bool old)
{
        if (enable) {
                intel_de_write(display, SERR_INT,
                               SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder));

                if (!cpt_can_enable_serr_int(display))
                        return;

                ibx_enable_display_interrupt(display, SDE_ERROR_CPT);
        } else {
                ibx_disable_display_interrupt(display, SDE_ERROR_CPT);

                if (old && intel_de_read(display, SERR_INT) &
                    SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder)) {
                        drm_err(display->drm,
                                "uncleared pch fifo underrun on pch transcoder %c\n",
                                pipe_name(pch_transcoder));
                }
        }
}

static bool __intel_set_cpu_fifo_underrun_reporting(struct intel_display *display,
                                                    enum pipe pipe, bool enable)
{
        struct intel_crtc *crtc = intel_crtc_for_pipe(display, pipe);
        bool old;

        lockdep_assert_held(&display->irq.lock);

        old = !crtc->cpu_fifo_underrun_disabled;
        crtc->cpu_fifo_underrun_disabled = !enable;

        /*
         * The debug bits get latched at the time of the FIFO underrun ISR bit
         * getting set.  That means that any non-zero debug bit that is read when
         * handling a FIFO underrun interrupt has the potential to belong to
         * another underrun event (past or future).  To alleviate this problem,
         * let's clear existing bits before enabling the interrupt, so that at
         * least we don't get information that is too out-of-date.
         */
        if (enable && !old)
                read_underrun_dbg_info(display, pipe, false);

        if (HAS_GMCH(display))
                i9xx_set_fifo_underrun_reporting(display, pipe, enable, old);
        else if (display->platform.ironlake || display->platform.sandybridge)
                ilk_set_fifo_underrun_reporting(display, pipe, enable);
        else if (DISPLAY_VER(display) == 7)
                ivb_set_fifo_underrun_reporting(display, pipe, enable, old);
        else if (DISPLAY_VER(display) >= 8)
                bdw_set_fifo_underrun_reporting(display, pipe, enable);

        return old;
}

/**
 * intel_set_cpu_fifo_underrun_reporting - set cpu fifo underrun reporting state
 * @display: display device instance
 * @pipe: (CPU) pipe to set state for
 * @enable: whether underruns should be reported or not
 *
 * This function sets the fifo underrun state for @pipe. It is used in the
 * modeset code to avoid false positives since on many platforms underruns are
 * expected when disabling or enabling the pipe.
 *
 * Notice that on some platforms disabling underrun reports for one pipe
 * disables for all due to shared interrupts. Actual reporting is still per-pipe
 * though.
 *
 * Returns the previous state of underrun reporting.
 */
bool intel_set_cpu_fifo_underrun_reporting(struct intel_display *display,
                                           enum pipe pipe, bool enable)
{
        unsigned long flags;
        bool ret;

        spin_lock_irqsave(&display->irq.lock, flags);
        ret = __intel_set_cpu_fifo_underrun_reporting(display, pipe, enable);
        spin_unlock_irqrestore(&display->irq.lock, flags);

        return ret;
}

/**
 * intel_set_pch_fifo_underrun_reporting - set PCH fifo underrun reporting state
 * @display: display device instance
 * @pch_transcoder: the PCH transcoder (same as pipe on IVB and older)
 * @enable: whether underruns should be reported or not
 *
 * This function makes us disable or enable PCH fifo underruns for a specific
 * PCH transcoder. Notice that on some PCHs (e.g. CPT/PPT), disabling FIFO
 * underrun reporting for one transcoder may also disable all the other PCH
 * error interruts for the other transcoders, due to the fact that there's just
 * one interrupt mask/enable bit for all the transcoders.
 *
 * Returns the previous state of underrun reporting.
 */
bool intel_set_pch_fifo_underrun_reporting(struct intel_display *display,
                                           enum pipe pch_transcoder,
                                           bool enable)
{
        struct intel_crtc *crtc = intel_crtc_for_pipe(display, pch_transcoder);
        unsigned long flags;
        bool old;

        /*
         * NOTE: Pre-LPT has a fixed cpu pipe -> pch transcoder mapping, but LPT
         * has only one pch transcoder A that all pipes can use. To avoid racy
         * pch transcoder -> pipe lookups from interrupt code simply store the
         * underrun statistics in crtc A. Since we never expose this anywhere
         * nor use it outside of the fifo underrun code here using the "wrong"
         * crtc on LPT won't cause issues.
         */

        spin_lock_irqsave(&display->irq.lock, flags);

        old = !crtc->pch_fifo_underrun_disabled;
        crtc->pch_fifo_underrun_disabled = !enable;

        if (HAS_PCH_IBX(display))
                ibx_set_fifo_underrun_reporting(display,
                                                pch_transcoder,
                                                enable);
        else
                cpt_set_fifo_underrun_reporting(display,
                                                pch_transcoder,
                                                enable, old);

        spin_unlock_irqrestore(&display->irq.lock, flags);
        return old;
}

/**
 * intel_cpu_fifo_underrun_irq_handler - handle CPU fifo underrun interrupt
 * @display: display device instance
 * @pipe: (CPU) pipe to set state for
 *
 * This handles a CPU fifo underrun interrupt, generating an underrun warning
 * into dmesg if underrun reporting is enabled and then disables the underrun
 * interrupt to avoid an irq storm.
 */
void intel_cpu_fifo_underrun_irq_handler(struct intel_display *display,
                                         enum pipe pipe)
{
        struct intel_crtc *crtc = intel_crtc_for_pipe(display, pipe);

        /* We may be called too early in init, thanks BIOS! */
        if (crtc == NULL)
                return;

        /* GMCH can't disable fifo underruns, filter them. */
        if (HAS_GMCH(display) &&
            crtc->cpu_fifo_underrun_disabled)
                return;

        if (intel_set_cpu_fifo_underrun_reporting(display, pipe, false)) {
                trace_intel_cpu_fifo_underrun(display, pipe);

                drm_err(display->drm, "CPU pipe %c FIFO underrun\n", pipe_name(pipe));

                read_underrun_dbg_info(display, pipe, true);
        }

        intel_fbc_handle_fifo_underrun_irq(display);
}

/**
 * intel_pch_fifo_underrun_irq_handler - handle PCH fifo underrun interrupt
 * @display: display device instance
 * @pch_transcoder: the PCH transcoder (same as pipe on IVB and older)
 *
 * This handles a PCH fifo underrun interrupt, generating an underrun warning
 * into dmesg if underrun reporting is enabled and then disables the underrun
 * interrupt to avoid an irq storm.
 */
void intel_pch_fifo_underrun_irq_handler(struct intel_display *display,
                                         enum pipe pch_transcoder)
{
        if (intel_set_pch_fifo_underrun_reporting(display, pch_transcoder,
                                                  false)) {
                trace_intel_pch_fifo_underrun(display, pch_transcoder);
                drm_err(display->drm, "PCH transcoder %c FIFO underrun\n",
                        pipe_name(pch_transcoder));
        }
}

/**
 * intel_check_cpu_fifo_underruns - check for CPU fifo underruns immediately
 * @display: display device instance
 *
 * Check for CPU fifo underruns immediately. Useful on IVB/HSW where the shared
 * error interrupt may have been disabled, and so CPU fifo underruns won't
 * necessarily raise an interrupt, and on GMCH platforms where underruns never
 * raise an interrupt.
 */
void intel_check_cpu_fifo_underruns(struct intel_display *display)
{
        struct intel_crtc *crtc;

        spin_lock_irq(&display->irq.lock);

        for_each_intel_crtc(display, crtc) {
                if (crtc->cpu_fifo_underrun_disabled)
                        continue;

                if (HAS_GMCH(display))
                        i9xx_check_fifo_underruns(crtc);
                else if (DISPLAY_VER(display) == 7)
                        ivb_check_fifo_underruns(crtc);
        }

        spin_unlock_irq(&display->irq.lock);
}

/**
 * intel_check_pch_fifo_underruns - check for PCH fifo underruns immediately
 * @display: display device instance
 *
 * Check for PCH fifo underruns immediately. Useful on CPT/PPT where the shared
 * error interrupt may have been disabled, and so PCH fifo underruns won't
 * necessarily raise an interrupt.
 */
void intel_check_pch_fifo_underruns(struct intel_display *display)
{
        struct intel_crtc *crtc;

        spin_lock_irq(&display->irq.lock);

        for_each_intel_crtc(display, crtc) {
                if (crtc->pch_fifo_underrun_disabled)
                        continue;

                if (HAS_PCH_CPT(display))
                        cpt_check_pch_fifo_underruns(crtc);
        }

        spin_unlock_irq(&display->irq.lock);
}

void intel_init_fifo_underrun_reporting(struct intel_display *display,
                                        struct intel_crtc *crtc,
                                        bool enable)
{
        crtc->cpu_fifo_underrun_disabled = !enable;

        /*
         * We track the PCH trancoder underrun reporting state
         * within the crtc. With crtc for pipe A housing the underrun
         * reporting state for PCH transcoder A, crtc for pipe B housing
         * it for PCH transcoder B, etc. LPT-H has only PCH transcoder A,
         * and marking underrun reporting as disabled for the non-existing
         * PCH transcoders B and C would prevent enabling the south
         * error interrupt (see cpt_can_enable_serr_int()).
         */
        if (intel_has_pch_trancoder(display, crtc->pipe))
                crtc->pch_fifo_underrun_disabled = !enable;
}