// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * OMAP1 Special OptimiSed Screen Interface support
 *
 * Copyright (C) 2004-2005 Nokia Corporation
 * Author: Juha Yrjölä <juha.yrjola@nokia.com>
 */
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/clk.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/interrupt.h>

#include <linux/omap-dma.h>
#include <linux/soc/ti/omap1-io.h>

#include "omapfb.h"
#include "lcd_dma.h"
#include "lcdc.h"

#define MODULE_NAME             "omapfb-sossi"

#define OMAP_SOSSI_BASE         0xfffbac00
#define SOSSI_ID_REG            0x00
#define SOSSI_INIT1_REG         0x04
#define SOSSI_INIT2_REG         0x08
#define SOSSI_INIT3_REG         0x0c
#define SOSSI_FIFO_REG          0x10
#define SOSSI_REOTABLE_REG      0x14
#define SOSSI_TEARING_REG       0x18
#define SOSSI_INIT1B_REG        0x1c
#define SOSSI_FIFOB_REG         0x20

#define DMA_GSCR          0xfffedc04
#define DMA_LCD_CCR       0xfffee3c2
#define DMA_LCD_CTRL      0xfffee3c4
#define DMA_LCD_LCH_CTRL  0xfffee3ea

#define CONF_SOSSI_RESET_R      (1 << 23)

#define RD_ACCESS               0
#define WR_ACCESS               1

#define SOSSI_MAX_XMIT_BYTES    (512 * 1024)

static struct {
        void __iomem    *base;
        struct clk      *fck;
        unsigned long   fck_hz;
        spinlock_t      lock;
        int             bus_pick_count;
        int             bus_pick_width;
        int             tearsync_mode;
        int             tearsync_line;
        void            (*lcdc_callback)(void *data);
        void            *lcdc_callback_data;
        int             vsync_dma_pending;
        /* timing for read and write access */
        int             clk_div;
        u8              clk_tw0[2];
        u8              clk_tw1[2];
        /*
         * if last_access is the same as current we don't have to change
         * the timings
         */
        int             last_access;

        struct omapfb_device    *fbdev;
} sossi;

static inline u32 sossi_read_reg(int reg)
{
        return readl(sossi.base + reg);
}

static inline u16 sossi_read_reg16(int reg)
{
        return readw(sossi.base + reg);
}

static inline u8 sossi_read_reg8(int reg)
{
        return readb(sossi.base + reg);
}

static inline void sossi_write_reg(int reg, u32 value)
{
        writel(value, sossi.base + reg);
}

static inline void sossi_write_reg16(int reg, u16 value)
{
        writew(value, sossi.base + reg);
}

static inline void sossi_write_reg8(int reg, u8 value)
{
        writeb(value, sossi.base + reg);
}

static void sossi_set_bits(int reg, u32 bits)
{
        sossi_write_reg(reg, sossi_read_reg(reg) | bits);
}

static void sossi_clear_bits(int reg, u32 bits)
{
        sossi_write_reg(reg, sossi_read_reg(reg) & ~bits);
}

#define HZ_TO_PS(x)     (1000000000 / (x / 1000))

static u32 ps_to_sossi_ticks(u32 ps, int div)
{
        u32 clk_period = HZ_TO_PS(sossi.fck_hz) * div;
        return (clk_period + ps - 1) / clk_period;
}

static int calc_rd_timings(struct extif_timings *t)
{
        u32 tw0, tw1;
        int reon, reoff, recyc, actim;
        int div = t->clk_div;

        /*
         * Make sure that after conversion it still holds that:
         * reoff > reon, recyc >= reoff, actim > reon
         */
        reon = ps_to_sossi_ticks(t->re_on_time, div);
        /* reon will be exactly one sossi tick */
        if (reon > 1)
                return -1;

        reoff = ps_to_sossi_ticks(t->re_off_time, div);

        if (reoff <= reon)
                reoff = reon + 1;

        tw0 = reoff - reon;
        if (tw0 > 0x10)
                return -1;

        recyc = ps_to_sossi_ticks(t->re_cycle_time, div);
        if (recyc <= reoff)
                recyc = reoff + 1;

        tw1 = recyc - tw0;
        /* values less then 3 result in the SOSSI block resetting itself */
        if (tw1 < 3)
                tw1 = 3;
        if (tw1 > 0x40)
                return -1;

        actim = ps_to_sossi_ticks(t->access_time, div);
        if (actim < reoff)
                actim++;
        /*
         * access time (data hold time) will be exactly one sossi
         * tick
         */
        if (actim - reoff > 1)
                return -1;

        t->tim[0] = tw0 - 1;
        t->tim[1] = tw1 - 1;

        return 0;
}

static int calc_wr_timings(struct extif_timings *t)
{
        u32 tw0, tw1;
        int weon, weoff, wecyc;
        int div = t->clk_div;

        /*
         * Make sure that after conversion it still holds that:
         * weoff > weon, wecyc >= weoff
         */
        weon = ps_to_sossi_ticks(t->we_on_time, div);
        /* weon will be exactly one sossi tick */
        if (weon > 1)
                return -1;

        weoff = ps_to_sossi_ticks(t->we_off_time, div);
        if (weoff <= weon)
                weoff = weon + 1;
        tw0 = weoff - weon;
        if (tw0 > 0x10)
                return -1;

        wecyc = ps_to_sossi_ticks(t->we_cycle_time, div);
        if (wecyc <= weoff)
                wecyc = weoff + 1;

        tw1 = wecyc - tw0;
        /* values less then 3 result in the SOSSI block resetting itself */
        if (tw1 < 3)
                tw1 = 3;
        if (tw1 > 0x40)
                return -1;

        t->tim[2] = tw0 - 1;
        t->tim[3] = tw1 - 1;

        return 0;
}

static void _set_timing(int div, int tw0, int tw1)
{
        u32 l;

#ifdef VERBOSE
        dev_dbg(sossi.fbdev->dev, "Using TW0 = %d, TW1 = %d, div = %d\n",
                 tw0 + 1, tw1 + 1, div);
#endif

        clk_set_rate(sossi.fck, sossi.fck_hz / div);
        clk_enable(sossi.fck);
        l = sossi_read_reg(SOSSI_INIT1_REG);
        l &= ~((0x0f << 20) | (0x3f << 24));
        l |= (tw0 << 20) | (tw1 << 24);
        sossi_write_reg(SOSSI_INIT1_REG, l);
        clk_disable(sossi.fck);
}

static void _set_bits_per_cycle(int bus_pick_count, int bus_pick_width)
{
        u32 l;

        l = sossi_read_reg(SOSSI_INIT3_REG);
        l &= ~0x3ff;
        l |= ((bus_pick_count - 1) << 5) | ((bus_pick_width - 1) & 0x1f);
        sossi_write_reg(SOSSI_INIT3_REG, l);
}

static void _set_tearsync_mode(int mode, unsigned line)
{
        u32 l;

        l = sossi_read_reg(SOSSI_TEARING_REG);
        l &= ~(((1 << 11) - 1) << 15);
        l |= line << 15;
        l &= ~(0x3 << 26);
        l |= mode << 26;
        sossi_write_reg(SOSSI_TEARING_REG, l);
        if (mode)
                sossi_set_bits(SOSSI_INIT2_REG, 1 << 6);        /* TE logic */
        else
                sossi_clear_bits(SOSSI_INIT2_REG, 1 << 6);
}

static inline void set_timing(int access)
{
        if (access != sossi.last_access) {
                sossi.last_access = access;
                _set_timing(sossi.clk_div,
                            sossi.clk_tw0[access], sossi.clk_tw1[access]);
        }
}

static void sossi_start_transfer(void)
{
        /* WE */
        sossi_clear_bits(SOSSI_INIT2_REG, 1 << 4);
        /* CS active low */
        sossi_clear_bits(SOSSI_INIT1_REG, 1 << 30);
}

static void sossi_stop_transfer(void)
{
        /* WE */
        sossi_set_bits(SOSSI_INIT2_REG, 1 << 4);
        /* CS active low */
        sossi_set_bits(SOSSI_INIT1_REG, 1 << 30);
}

static void wait_end_of_write(void)
{
        /* Before reading we must check if some writings are going on */
        while (!(sossi_read_reg(SOSSI_INIT2_REG) & (1 << 3)));
}

static void send_data(const void *data, unsigned int len)
{
        while (len >= 4) {
                sossi_write_reg(SOSSI_FIFO_REG, *(const u32 *) data);
                len -= 4;
                data += 4;
        }
        while (len >= 2) {
                sossi_write_reg16(SOSSI_FIFO_REG, *(const u16 *) data);
                len -= 2;
                data += 2;
        }
        while (len) {
                sossi_write_reg8(SOSSI_FIFO_REG, *(const u8 *) data);
                len--;
                data++;
        }
}

static void set_cycles(unsigned int len)
{
        unsigned long nr_cycles = len / (sossi.bus_pick_width / 8);

        BUG_ON((nr_cycles - 1) & ~0x3ffff);

        sossi_clear_bits(SOSSI_INIT1_REG, 0x3ffff);
        sossi_set_bits(SOSSI_INIT1_REG, (nr_cycles - 1) & 0x3ffff);
}

static int sossi_convert_timings(struct extif_timings *t)
{
        int r = 0;
        int div = t->clk_div;

        t->converted = 0;

        if (div <= 0 || div > 8)
                return -1;

        /* no CS on SOSSI, so ignore cson, csoff, cs_pulsewidth */
        if ((r = calc_rd_timings(t)) < 0)
                return r;

        if ((r = calc_wr_timings(t)) < 0)
                return r;

        t->tim[4] = div;

        t->converted = 1;

        return 0;
}

static void sossi_set_timings(const struct extif_timings *t)
{
        BUG_ON(!t->converted);

        sossi.clk_tw0[RD_ACCESS] = t->tim[0];
        sossi.clk_tw1[RD_ACCESS] = t->tim[1];

        sossi.clk_tw0[WR_ACCESS] = t->tim[2];
        sossi.clk_tw1[WR_ACCESS] = t->tim[3];

        sossi.clk_div = t->tim[4];
}

static void sossi_get_clk_info(u32 *clk_period, u32 *max_clk_div)
{
        *clk_period = HZ_TO_PS(sossi.fck_hz);
        *max_clk_div = 8;
}

static void sossi_set_bits_per_cycle(int bpc)
{
        int bus_pick_count, bus_pick_width;

        /*
         * We set explicitly the bus_pick_count as well, although
         * with remapping/reordering disabled it will be calculated by HW
         * as (32 / bus_pick_width).
         */
        switch (bpc) {
        case 8:
                bus_pick_count = 4;
                bus_pick_width = 8;
                break;
        case 16:
                bus_pick_count = 2;
                bus_pick_width = 16;
                break;
        default:
                BUG();
                return;
        }
        sossi.bus_pick_width = bus_pick_width;
        sossi.bus_pick_count = bus_pick_count;
}

static int sossi_setup_tearsync(unsigned pin_cnt,
                                unsigned hs_pulse_time, unsigned vs_pulse_time,
                                int hs_pol_inv, int vs_pol_inv, int div)
{
        int hs, vs;
        u32 l;

        if (pin_cnt != 1 || div < 1 || div > 8)
                return -EINVAL;

        hs = ps_to_sossi_ticks(hs_pulse_time, div);
        vs = ps_to_sossi_ticks(vs_pulse_time, div);
        if (vs < 8 || vs <= hs || vs >= (1 << 12))
                return -EDOM;
        vs /= 8;
        vs--;
        if (hs > 8)
                hs = 8;
        if (hs)
                hs--;

        dev_dbg(sossi.fbdev->dev,
                "setup_tearsync: hs %d vs %d hs_inv %d vs_inv %d\n",
                hs, vs, hs_pol_inv, vs_pol_inv);

        clk_enable(sossi.fck);
        l = sossi_read_reg(SOSSI_TEARING_REG);
        l &= ~((1 << 15) - 1);
        l |= vs << 3;
        l |= hs;
        if (hs_pol_inv)
                l |= 1 << 29;
        else
                l &= ~(1 << 29);
        if (vs_pol_inv)
                l |= 1 << 28;
        else
                l &= ~(1 << 28);
        sossi_write_reg(SOSSI_TEARING_REG, l);
        clk_disable(sossi.fck);

        return 0;
}

static int sossi_enable_tearsync(int enable, unsigned line)
{
        int mode;

        dev_dbg(sossi.fbdev->dev, "tearsync %d line %d\n", enable, line);
        if (line >= 1 << 11)
                return -EINVAL;
        if (enable) {
                if (line)
                        mode = 2;               /* HS or VS */
                else
                        mode = 3;               /* VS only */
        } else
                mode = 0;
        sossi.tearsync_line = line;
        sossi.tearsync_mode = mode;

        return 0;
}

static void sossi_write_command(const void *data, unsigned int len)
{
        clk_enable(sossi.fck);
        set_timing(WR_ACCESS);
        _set_bits_per_cycle(sossi.bus_pick_count, sossi.bus_pick_width);
        /* CMD#/DATA */
        sossi_clear_bits(SOSSI_INIT1_REG, 1 << 18);
        set_cycles(len);
        sossi_start_transfer();
        send_data(data, len);
        sossi_stop_transfer();
        wait_end_of_write();
        clk_disable(sossi.fck);
}

static void sossi_write_data(const void *data, unsigned int len)
{
        clk_enable(sossi.fck);
        set_timing(WR_ACCESS);
        _set_bits_per_cycle(sossi.bus_pick_count, sossi.bus_pick_width);
        /* CMD#/DATA */
        sossi_set_bits(SOSSI_INIT1_REG, 1 << 18);
        set_cycles(len);
        sossi_start_transfer();
        send_data(data, len);
        sossi_stop_transfer();
        wait_end_of_write();
        clk_disable(sossi.fck);
}

static void sossi_transfer_area(int width, int height,
                                void (callback)(void *data), void *data)
{
        BUG_ON(callback == NULL);

        sossi.lcdc_callback = callback;
        sossi.lcdc_callback_data = data;

        clk_enable(sossi.fck);
        set_timing(WR_ACCESS);
        _set_bits_per_cycle(sossi.bus_pick_count, sossi.bus_pick_width);
        _set_tearsync_mode(sossi.tearsync_mode, sossi.tearsync_line);
        /* CMD#/DATA */
        sossi_set_bits(SOSSI_INIT1_REG, 1 << 18);
        set_cycles(width * height * sossi.bus_pick_width / 8);

        sossi_start_transfer();
        if (sossi.tearsync_mode) {
                /*
                 * Wait for the sync signal and start the transfer only
                 * then. We can't seem to be able to use HW sync DMA for
                 * this since LCD DMA shows huge latencies, as if it
                 * would ignore some of the DMA requests from SoSSI.
                 */
                unsigned long flags;

                spin_lock_irqsave(&sossi.lock, flags);
                sossi.vsync_dma_pending++;
                spin_unlock_irqrestore(&sossi.lock, flags);
        } else
                /* Just start the transfer right away. */
                omap_enable_lcd_dma();
}

static void sossi_dma_callback(void *data)
{
        omap_stop_lcd_dma();
        sossi_stop_transfer();
        clk_disable(sossi.fck);
        sossi.lcdc_callback(sossi.lcdc_callback_data);
}

static void sossi_read_data(void *data, unsigned int len)
{
        clk_enable(sossi.fck);
        set_timing(RD_ACCESS);
        _set_bits_per_cycle(sossi.bus_pick_count, sossi.bus_pick_width);
        /* CMD#/DATA */
        sossi_set_bits(SOSSI_INIT1_REG, 1 << 18);
        set_cycles(len);
        sossi_start_transfer();
        while (len >= 4) {
                *(u32 *) data = sossi_read_reg(SOSSI_FIFO_REG);
                len -= 4;
                data += 4;
        }
        while (len >= 2) {
                *(u16 *) data = sossi_read_reg16(SOSSI_FIFO_REG);
                len -= 2;
                data += 2;
        }
        while (len) {
                *(u8 *) data = sossi_read_reg8(SOSSI_FIFO_REG);
                len--;
                data++;
        }
        sossi_stop_transfer();
        clk_disable(sossi.fck);
}

static irqreturn_t sossi_match_irq(int irq, void *data)
{
        unsigned long flags;

        spin_lock_irqsave(&sossi.lock, flags);
        if (sossi.vsync_dma_pending) {
                sossi.vsync_dma_pending--;
                omap_enable_lcd_dma();
        }
        spin_unlock_irqrestore(&sossi.lock, flags);
        return IRQ_HANDLED;
}

static int sossi_init(struct omapfb_device *fbdev)
{
        u32 l, k;
        struct clk *fck;
        struct clk *dpll1out_ck;
        int r;

        sossi.base = ioremap(OMAP_SOSSI_BASE, SZ_1K);
        if (!sossi.base) {
                dev_err(fbdev->dev, "can't ioremap SoSSI\n");
                return -ENOMEM;
        }

        sossi.fbdev = fbdev;
        spin_lock_init(&sossi.lock);

        dpll1out_ck = clk_get(fbdev->dev, "ck_dpll1out");
        if (IS_ERR(dpll1out_ck)) {
                dev_err(fbdev->dev, "can't get DPLL1OUT clock\n");
                return PTR_ERR(dpll1out_ck);
        }
        /*
         * We need the parent clock rate, which we might divide further
         * depending on the timing requirements of the controller. See
         * _set_timings.
         */
        sossi.fck_hz = clk_get_rate(dpll1out_ck);
        clk_put(dpll1out_ck);

        fck = clk_get(fbdev->dev, "ck_sossi");
        if (IS_ERR(fck)) {
                dev_err(fbdev->dev, "can't get SoSSI functional clock\n");
                return PTR_ERR(fck);
        }
        sossi.fck = fck;

        /* Reset and enable the SoSSI module */
        l = omap_readl(MOD_CONF_CTRL_1);
        l |= CONF_SOSSI_RESET_R;
        omap_writel(l, MOD_CONF_CTRL_1);
        l &= ~CONF_SOSSI_RESET_R;
        omap_writel(l, MOD_CONF_CTRL_1);

        clk_prepare_enable(sossi.fck);
        l = omap_readl(ARM_IDLECT2);
        l &= ~(1 << 8);                 /* DMACK_REQ */
        omap_writel(l, ARM_IDLECT2);

        l = sossi_read_reg(SOSSI_INIT2_REG);
        /* Enable and reset the SoSSI block */
        l |= (1 << 0) | (1 << 1);
        sossi_write_reg(SOSSI_INIT2_REG, l);
        /* Take SoSSI out of reset */
        l &= ~(1 << 1);
        sossi_write_reg(SOSSI_INIT2_REG, l);

        sossi_write_reg(SOSSI_ID_REG, 0);
        l = sossi_read_reg(SOSSI_ID_REG);
        k = sossi_read_reg(SOSSI_ID_REG);

        if (l != 0x55555555 || k != 0xaaaaaaaa) {
                dev_err(fbdev->dev,
                        "invalid SoSSI sync pattern: %08x, %08x\n", l, k);
                r = -ENODEV;
                goto err;
        }

        if ((r = omap_lcdc_set_dma_callback(sossi_dma_callback, NULL)) < 0) {
                dev_err(fbdev->dev, "can't get LCDC IRQ\n");
                r = -ENODEV;
                goto err;
        }

        l = sossi_read_reg(SOSSI_ID_REG); /* Component code */
        l = sossi_read_reg(SOSSI_ID_REG);
        dev_info(fbdev->dev, "SoSSI version %d.%d initialized\n",
                l >> 16, l & 0xffff);

        l = sossi_read_reg(SOSSI_INIT1_REG);
        l |= (1 << 19); /* DMA_MODE */
        l &= ~(1 << 31); /* REORDERING */
        sossi_write_reg(SOSSI_INIT1_REG, l);

        if ((r = request_irq(fbdev->ext_irq, sossi_match_irq,
                             IRQ_TYPE_EDGE_FALLING,
             "sossi_match", sossi.fbdev->dev)) < 0) {
                dev_err(sossi.fbdev->dev, "can't get SoSSI match IRQ\n");
                goto err;
        }

        clk_disable(sossi.fck);
        return 0;

err:
        clk_disable_unprepare(sossi.fck);
        clk_put(sossi.fck);
        return r;
}

static void sossi_cleanup(void)
{
        omap_lcdc_free_dma_callback();
        clk_unprepare(sossi.fck);
        clk_put(sossi.fck);
        iounmap(sossi.base);
}

struct lcd_ctrl_extif omap1_ext_if = {
        .init                   = sossi_init,
        .cleanup                = sossi_cleanup,
        .get_clk_info           = sossi_get_clk_info,
        .convert_timings        = sossi_convert_timings,
        .set_timings            = sossi_set_timings,
        .set_bits_per_cycle     = sossi_set_bits_per_cycle,
        .setup_tearsync         = sossi_setup_tearsync,
        .enable_tearsync        = sossi_enable_tearsync,
        .write_command          = sossi_write_command,
        .read_data              = sossi_read_data,
        .write_data             = sossi_write_data,
        .transfer_area          = sossi_transfer_area,

        .max_transmit_size      = SOSSI_MAX_XMIT_BYTES,
};