// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/drivers/video/ep93xx-fb.c
 *
 * Framebuffer support for the EP93xx series.
 *
 * Copyright (C) 2007 Bluewater Systems Ltd
 * Author: Ryan Mallon
 *
 * Copyright (c) 2009 H Hartley Sweeten <hsweeten@visionengravers.com>
 *
 * Based on the Cirrus Logic ep93xxfb driver, and various other ep93xxfb
 * drivers.
 */

#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/fb.h>
#include <linux/io.h>

#include <linux/platform_data/video-ep93xx.h>

/* Vertical Frame Timing Registers */
#define EP93XXFB_VLINES_TOTAL                   0x0000  /* SW locked */
#define EP93XXFB_VSYNC                          0x0004  /* SW locked */
#define EP93XXFB_VACTIVE                        0x0008  /* SW locked */
#define EP93XXFB_VBLANK                         0x0228  /* SW locked */
#define EP93XXFB_VCLK                           0x000c  /* SW locked */

/* Horizontal Frame Timing Registers */
#define EP93XXFB_HCLKS_TOTAL                    0x0010  /* SW locked */
#define EP93XXFB_HSYNC                          0x0014  /* SW locked */
#define EP93XXFB_HACTIVE                        0x0018  /* SW locked */
#define EP93XXFB_HBLANK                         0x022c  /* SW locked */
#define EP93XXFB_HCLK                           0x001c  /* SW locked */

/* Frame Buffer Memory Configuration Registers */
#define EP93XXFB_SCREEN_PAGE                    0x0028
#define EP93XXFB_SCREEN_HPAGE                   0x002c
#define EP93XXFB_SCREEN_LINES                   0x0030
#define EP93XXFB_LINE_LENGTH                    0x0034
#define EP93XXFB_VLINE_STEP                     0x0038
#define EP93XXFB_LINE_CARRY                     0x003c  /* SW locked */
#define EP93XXFB_EOL_OFFSET                     0x0230

/* Other Video Registers */
#define EP93XXFB_BRIGHTNESS                     0x0020
#define EP93XXFB_ATTRIBS                        0x0024  /* SW locked */
#define EP93XXFB_SWLOCK                         0x007c  /* SW locked */
#define EP93XXFB_AC_RATE                        0x0214
#define EP93XXFB_FIFO_LEVEL                     0x0234
#define EP93XXFB_PIXELMODE                      0x0054
#define EP93XXFB_PIXELMODE_32BPP                (0x7 << 0)
#define EP93XXFB_PIXELMODE_24BPP                (0x6 << 0)
#define EP93XXFB_PIXELMODE_16BPP                (0x4 << 0)
#define EP93XXFB_PIXELMODE_8BPP                 (0x2 << 0)
#define EP93XXFB_PIXELMODE_SHIFT_1P_24B         (0x0 << 3)
#define EP93XXFB_PIXELMODE_SHIFT_1P_18B         (0x1 << 3)
#define EP93XXFB_PIXELMODE_COLOR_LUT            (0x0 << 10)
#define EP93XXFB_PIXELMODE_COLOR_888            (0x4 << 10)
#define EP93XXFB_PIXELMODE_COLOR_555            (0x5 << 10)
#define EP93XXFB_PARL_IF_OUT                    0x0058
#define EP93XXFB_PARL_IF_IN                     0x005c

/* Blink Control Registers */
#define EP93XXFB_BLINK_RATE                     0x0040
#define EP93XXFB_BLINK_MASK                     0x0044
#define EP93XXFB_BLINK_PATTRN                   0x0048
#define EP93XXFB_PATTRN_MASK                    0x004c
#define EP93XXFB_BKGRND_OFFSET                  0x0050

/* Hardware Cursor Registers */
#define EP93XXFB_CURSOR_ADR_START               0x0060
#define EP93XXFB_CURSOR_ADR_RESET               0x0064
#define EP93XXFB_CURSOR_SIZE                    0x0068
#define EP93XXFB_CURSOR_COLOR1                  0x006c
#define EP93XXFB_CURSOR_COLOR2                  0x0070
#define EP93XXFB_CURSOR_BLINK_COLOR1            0x021c
#define EP93XXFB_CURSOR_BLINK_COLOR2            0x0220
#define EP93XXFB_CURSOR_XY_LOC                  0x0074
#define EP93XXFB_CURSOR_DSCAN_HY_LOC            0x0078
#define EP93XXFB_CURSOR_BLINK_RATE_CTRL         0x0224

/* LUT Registers */
#define EP93XXFB_GRY_SCL_LUTR                   0x0080
#define EP93XXFB_GRY_SCL_LUTG                   0x0280
#define EP93XXFB_GRY_SCL_LUTB                   0x0300
#define EP93XXFB_LUT_SW_CONTROL                 0x0218
#define EP93XXFB_LUT_SW_CONTROL_SWTCH           (1 << 0)
#define EP93XXFB_LUT_SW_CONTROL_SSTAT           (1 << 1)
#define EP93XXFB_COLOR_LUT                      0x0400

/* Video Signature Registers */
#define EP93XXFB_VID_SIG_RSLT_VAL               0x0200
#define EP93XXFB_VID_SIG_CTRL                   0x0204
#define EP93XXFB_VSIG                           0x0208
#define EP93XXFB_HSIG                           0x020c
#define EP93XXFB_SIG_CLR_STR                    0x0210

/* Minimum / Maximum resolutions supported */
#define EP93XXFB_MIN_XRES                       64
#define EP93XXFB_MIN_YRES                       64
#define EP93XXFB_MAX_XRES                       1024
#define EP93XXFB_MAX_YRES                       768

struct ep93xx_fbi {
        struct ep93xxfb_mach_info       *mach_info;
        struct clk                      *clk;
        struct resource                 *res;
        void __iomem                    *mmio_base;
        unsigned int                    pseudo_palette[256];
};

static int check_screenpage_bug = 1;
module_param(check_screenpage_bug, int, 0644);
MODULE_PARM_DESC(check_screenpage_bug,
                 "Check for bit 27 screen page bug. Default = 1");

static inline unsigned int ep93xxfb_readl(struct ep93xx_fbi *fbi,
                                          unsigned int off)
{
        return __raw_readl(fbi->mmio_base + off);
}

static inline void ep93xxfb_writel(struct ep93xx_fbi *fbi,
                                   unsigned int val, unsigned int off)
{
        __raw_writel(val, fbi->mmio_base + off);
}

/*
 * Write to one of the locked raster registers.
 */
static inline void ep93xxfb_out_locked(struct ep93xx_fbi *fbi,
                                       unsigned int val, unsigned int reg)
{
        /*
         * We don't need a lock or delay here since the raster register
         * block will remain unlocked until the next access.
         */
        ep93xxfb_writel(fbi, 0xaa, EP93XXFB_SWLOCK);
        ep93xxfb_writel(fbi, val, reg);
}

static void ep93xxfb_set_video_attribs(struct fb_info *info)
{
        struct ep93xx_fbi *fbi = info->par;
        unsigned int attribs;

        attribs = EP93XXFB_ENABLE;
        attribs |= fbi->mach_info->flags;
        ep93xxfb_out_locked(fbi, attribs, EP93XXFB_ATTRIBS);
}

static int ep93xxfb_set_pixelmode(struct fb_info *info)
{
        struct ep93xx_fbi *fbi = info->par;
        unsigned int val;

        info->var.transp.offset = 0;
        info->var.transp.length = 0;

        switch (info->var.bits_per_pixel) {
        case 8:
                val = EP93XXFB_PIXELMODE_8BPP | EP93XXFB_PIXELMODE_COLOR_LUT |
                        EP93XXFB_PIXELMODE_SHIFT_1P_18B;

                info->var.red.offset    = 0;
                info->var.red.length    = 8;
                info->var.green.offset  = 0;
                info->var.green.length  = 8;
                info->var.blue.offset   = 0;
                info->var.blue.length   = 8;
                info->fix.visual        = FB_VISUAL_PSEUDOCOLOR;
                break;

        case 16:
                val = EP93XXFB_PIXELMODE_16BPP | EP93XXFB_PIXELMODE_COLOR_555 |
                        EP93XXFB_PIXELMODE_SHIFT_1P_18B;

                info->var.red.offset    = 11;
                info->var.red.length    = 5;
                info->var.green.offset  = 5;
                info->var.green.length  = 6;
                info->var.blue.offset   = 0;
                info->var.blue.length   = 5;
                info->fix.visual        = FB_VISUAL_TRUECOLOR;
                break;

        case 24:
                val = EP93XXFB_PIXELMODE_24BPP | EP93XXFB_PIXELMODE_COLOR_888 |
                        EP93XXFB_PIXELMODE_SHIFT_1P_24B;

                info->var.red.offset    = 16;
                info->var.red.length    = 8;
                info->var.green.offset  = 8;
                info->var.green.length  = 8;
                info->var.blue.offset   = 0;
                info->var.blue.length   = 8;
                info->fix.visual        = FB_VISUAL_TRUECOLOR;
                break;

        case 32:
                val = EP93XXFB_PIXELMODE_32BPP | EP93XXFB_PIXELMODE_COLOR_888 |
                        EP93XXFB_PIXELMODE_SHIFT_1P_24B;

                info->var.red.offset    = 16;
                info->var.red.length    = 8;
                info->var.green.offset  = 8;
                info->var.green.length  = 8;
                info->var.blue.offset   = 0;
                info->var.blue.length   = 8;
                info->fix.visual        = FB_VISUAL_TRUECOLOR;
                break;

        default:
                return -EINVAL;
        }

        ep93xxfb_writel(fbi, val, EP93XXFB_PIXELMODE);
        return 0;
}

static void ep93xxfb_set_timing(struct fb_info *info)
{
        struct ep93xx_fbi *fbi = info->par;
        unsigned int vlines_total, hclks_total, start, stop;

        vlines_total = info->var.yres + info->var.upper_margin +
                info->var.lower_margin + info->var.vsync_len - 1;

        hclks_total = info->var.xres + info->var.left_margin +
                info->var.right_margin + info->var.hsync_len - 1;

        ep93xxfb_out_locked(fbi, vlines_total, EP93XXFB_VLINES_TOTAL);
        ep93xxfb_out_locked(fbi, hclks_total, EP93XXFB_HCLKS_TOTAL);

        start = vlines_total;
        stop = vlines_total - info->var.vsync_len;
        ep93xxfb_out_locked(fbi, start | (stop << 16), EP93XXFB_VSYNC);

        start = vlines_total - info->var.vsync_len - info->var.upper_margin;
        stop = info->var.lower_margin - 1;
        ep93xxfb_out_locked(fbi, start | (stop << 16), EP93XXFB_VBLANK);
        ep93xxfb_out_locked(fbi, start | (stop << 16), EP93XXFB_VACTIVE);

        start = vlines_total;
        stop = vlines_total + 1;
        ep93xxfb_out_locked(fbi, start | (stop << 16), EP93XXFB_VCLK);

        start = hclks_total;
        stop = hclks_total - info->var.hsync_len;
        ep93xxfb_out_locked(fbi, start | (stop << 16), EP93XXFB_HSYNC);

        start = hclks_total - info->var.hsync_len - info->var.left_margin;
        stop = info->var.right_margin - 1;
        ep93xxfb_out_locked(fbi, start | (stop << 16), EP93XXFB_HBLANK);
        ep93xxfb_out_locked(fbi, start | (stop << 16), EP93XXFB_HACTIVE);

        start = hclks_total;
        stop = hclks_total;
        ep93xxfb_out_locked(fbi, start | (stop << 16), EP93XXFB_HCLK);

        ep93xxfb_out_locked(fbi, 0x0, EP93XXFB_LINE_CARRY);
}

static int ep93xxfb_set_par(struct fb_info *info)
{
        struct ep93xx_fbi *fbi = info->par;

        clk_set_rate(fbi->clk, 1000 * PICOS2KHZ(info->var.pixclock));

        ep93xxfb_set_timing(info);

        info->fix.line_length = info->var.xres_virtual *
                info->var.bits_per_pixel / 8;

        ep93xxfb_writel(fbi, info->fix.smem_start, EP93XXFB_SCREEN_PAGE);
        ep93xxfb_writel(fbi, info->var.yres - 1, EP93XXFB_SCREEN_LINES);
        ep93xxfb_writel(fbi, ((info->var.xres * info->var.bits_per_pixel)
                              / 32) - 1, EP93XXFB_LINE_LENGTH);
        ep93xxfb_writel(fbi, info->fix.line_length / 4, EP93XXFB_VLINE_STEP);
        ep93xxfb_set_video_attribs(info);
        return 0;
}

static int ep93xxfb_check_var(struct fb_var_screeninfo *var,
                              struct fb_info *info)
{
        int err;

        err = ep93xxfb_set_pixelmode(info);
        if (err)
                return err;

        var->xres = max_t(unsigned int, var->xres, EP93XXFB_MIN_XRES);
        var->xres = min_t(unsigned int, var->xres, EP93XXFB_MAX_XRES);
        var->xres_virtual = max(var->xres_virtual, var->xres);

        var->yres = max_t(unsigned int, var->yres, EP93XXFB_MIN_YRES);
        var->yres = min_t(unsigned int, var->yres, EP93XXFB_MAX_YRES);
        var->yres_virtual = max(var->yres_virtual, var->yres);

        return 0;
}

static int ep93xxfb_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
        unsigned int offset = vma->vm_pgoff << PAGE_SHIFT;

        vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);

        if (offset < info->fix.smem_len) {
                return dma_mmap_wc(info->device, vma, info->screen_base,
                                   info->fix.smem_start, info->fix.smem_len);
        }

        return -EINVAL;
}

static int ep93xxfb_blank(int blank_mode, struct fb_info *info)
{
        struct ep93xx_fbi *fbi = info->par;
        unsigned int attribs = ep93xxfb_readl(fbi, EP93XXFB_ATTRIBS);

        if (blank_mode) {
                if (fbi->mach_info->blank)
                        fbi->mach_info->blank(blank_mode, info);
                ep93xxfb_out_locked(fbi, attribs & ~EP93XXFB_ENABLE,
                                    EP93XXFB_ATTRIBS);
                clk_disable(fbi->clk);
        } else {
                clk_enable(fbi->clk);
                ep93xxfb_out_locked(fbi, attribs | EP93XXFB_ENABLE,
                                    EP93XXFB_ATTRIBS);
                if (fbi->mach_info->blank)
                        fbi->mach_info->blank(blank_mode, info);
        }

        return 0;
}

static inline int ep93xxfb_convert_color(int val, int width)
{
        return ((val << width) + 0x7fff - val) >> 16;
}

static int ep93xxfb_setcolreg(unsigned int regno, unsigned int red,
                              unsigned int green, unsigned int blue,
                              unsigned int transp, struct fb_info *info)
{
        struct ep93xx_fbi *fbi = info->par;
        unsigned int *pal = info->pseudo_palette;
        unsigned int ctrl, i, rgb, lut_current, lut_stat;

        switch (info->fix.visual) {
        case FB_VISUAL_PSEUDOCOLOR:
                if (regno > 255)
                        return 1;
                rgb = ((red & 0xff00) << 8) | (green & 0xff00) |
                        ((blue & 0xff00) >> 8);

                pal[regno] = rgb;
                ep93xxfb_writel(fbi, rgb, (EP93XXFB_COLOR_LUT + (regno << 2)));
                ctrl = ep93xxfb_readl(fbi, EP93XXFB_LUT_SW_CONTROL);
                lut_stat = !!(ctrl & EP93XXFB_LUT_SW_CONTROL_SSTAT);
                lut_current = !!(ctrl & EP93XXFB_LUT_SW_CONTROL_SWTCH);

                if (lut_stat == lut_current) {
                        for (i = 0; i < 256; i++) {
                                ep93xxfb_writel(fbi, pal[i],
                                        EP93XXFB_COLOR_LUT + (i << 2));
                        }

                        ep93xxfb_writel(fbi,
                                        ctrl ^ EP93XXFB_LUT_SW_CONTROL_SWTCH,
                                        EP93XXFB_LUT_SW_CONTROL);
                }
                break;

        case FB_VISUAL_TRUECOLOR:
                if (regno > 16)
                        return 1;

                red = ep93xxfb_convert_color(red, info->var.red.length);
                green = ep93xxfb_convert_color(green, info->var.green.length);
                blue = ep93xxfb_convert_color(blue, info->var.blue.length);
                transp = ep93xxfb_convert_color(transp,
                                                info->var.transp.length);

                pal[regno] = (red << info->var.red.offset) |
                        (green << info->var.green.offset) |
                        (blue << info->var.blue.offset) |
                        (transp << info->var.transp.offset);
                break;

        default:
                return 1;
        }

        return 0;
}

static const struct fb_ops ep93xxfb_ops = {
        .owner          = THIS_MODULE,
        __FB_DEFAULT_IOMEM_OPS_RDWR,
        .fb_check_var   = ep93xxfb_check_var,
        .fb_set_par     = ep93xxfb_set_par,
        .fb_blank       = ep93xxfb_blank,
        __FB_DEFAULT_IOMEM_OPS_DRAW,
        .fb_setcolreg   = ep93xxfb_setcolreg,
        .fb_mmap        = ep93xxfb_mmap,
};

static int ep93xxfb_alloc_videomem(struct fb_info *info)
{
        char __iomem *virt_addr;
        dma_addr_t phys_addr;
        unsigned int fb_size;

        /* Maximum 16bpp -> used memory is maximum x*y*2 bytes */
        fb_size = EP93XXFB_MAX_XRES * EP93XXFB_MAX_YRES * 2;

        virt_addr = dma_alloc_wc(info->device, fb_size, &phys_addr, GFP_KERNEL);
        if (!virt_addr)
                return -ENOMEM;

        /*
         * There is a bug in the ep93xx framebuffer which causes problems
         * if bit 27 of the physical address is set.
         * See: https://marc.info/?l=linux-arm-kernel&m=110061245502000&w=2
         * There does not seem to be any official errata for this, but I
         * have confirmed the problem exists on my hardware (ep9315) at
         * least.
         */
        if (check_screenpage_bug && phys_addr & (1 << 27)) {
                fb_err(info, "ep93xx framebuffer bug. phys addr (0x%x) "
                       "has bit 27 set: cannot init framebuffer\n",
                       phys_addr);

                dma_free_coherent(info->device, fb_size, virt_addr, phys_addr);
                return -ENOMEM;
        }

        info->fix.smem_start = phys_addr;
        info->fix.smem_len = fb_size;
        info->screen_base = virt_addr;

        return 0;
}

static void ep93xxfb_dealloc_videomem(struct fb_info *info)
{
        if (info->screen_base)
                dma_free_coherent(info->device, info->fix.smem_len,
                                  info->screen_base, info->fix.smem_start);
}

static int ep93xxfb_probe(struct platform_device *pdev)
{
        struct ep93xxfb_mach_info *mach_info = dev_get_platdata(&pdev->dev);
        struct fb_info *info;
        struct ep93xx_fbi *fbi;
        struct resource *res;
        char *video_mode;
        int err;

        if (!mach_info)
                return -EINVAL;

        info = framebuffer_alloc(sizeof(struct ep93xx_fbi), &pdev->dev);
        if (!info)
                return -ENOMEM;

        platform_set_drvdata(pdev, info);
        fbi = info->par;
        fbi->mach_info = mach_info;

        err = fb_alloc_cmap(&info->cmap, 256, 0);
        if (err)
                goto failed_cmap;

        err = ep93xxfb_alloc_videomem(info);
        if (err)
                goto failed_videomem;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                err = -ENXIO;
                goto failed_resource;
        }

        /*
         * FIXME - We don't do a request_mem_region here because we are
         * sharing the register space with the backlight driver (see
         * drivers/video/backlight/ep93xx_bl.c) and doing so will cause
         * the second loaded driver to return -EBUSY.
         *
         * NOTE: No locking is required; the backlight does not touch
         * any of the framebuffer registers.
         */
        fbi->res = res;
        fbi->mmio_base = devm_ioremap(&pdev->dev, res->start,
                                      resource_size(res));
        if (!fbi->mmio_base) {
                err = -ENXIO;
                goto failed_resource;
        }

        strcpy(info->fix.id, pdev->name);
        info->fbops             = &ep93xxfb_ops;
        info->fix.type          = FB_TYPE_PACKED_PIXELS;
        info->fix.accel         = FB_ACCEL_NONE;
        info->var.activate      = FB_ACTIVATE_NOW;
        info->var.vmode         = FB_VMODE_NONINTERLACED;
        info->node              = -1;
        info->state             = FBINFO_STATE_RUNNING;
        info->pseudo_palette    = &fbi->pseudo_palette;

        fb_get_options("ep93xx-fb", &video_mode);
        err = fb_find_mode(&info->var, info, video_mode,
                           NULL, 0, NULL, 16);
        if (err == 0) {
                fb_err(info, "No suitable video mode found\n");
                err = -EINVAL;
                goto failed_resource;
        }

        if (mach_info->setup) {
                err = mach_info->setup(pdev);
                if (err)
                        goto failed_resource;
        }

        err = ep93xxfb_check_var(&info->var, info);
        if (err)
                goto failed_check;

        fbi->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(fbi->clk)) {
                err = PTR_ERR(fbi->clk);
                fbi->clk = NULL;
                goto failed_check;
        }

        ep93xxfb_set_par(info);
        err = clk_prepare_enable(fbi->clk);
        if (err)
                goto failed_check;

        err = register_framebuffer(info);
        if (err)
                goto failed_framebuffer;

        fb_info(info, "registered. Mode = %dx%d-%d\n",
                info->var.xres, info->var.yres, info->var.bits_per_pixel);
        return 0;

failed_framebuffer:
        clk_disable_unprepare(fbi->clk);
failed_check:
        if (fbi->mach_info->teardown)
                fbi->mach_info->teardown(pdev);
failed_resource:
        ep93xxfb_dealloc_videomem(info);
failed_videomem:
        fb_dealloc_cmap(&info->cmap);
failed_cmap:
        kfree(info);

        return err;
}

static void ep93xxfb_remove(struct platform_device *pdev)
{
        struct fb_info *info = platform_get_drvdata(pdev);
        struct ep93xx_fbi *fbi = info->par;

        unregister_framebuffer(info);
        clk_disable_unprepare(fbi->clk);
        ep93xxfb_dealloc_videomem(info);
        fb_dealloc_cmap(&info->cmap);

        if (fbi->mach_info->teardown)
                fbi->mach_info->teardown(pdev);

        kfree(info);
}

static struct platform_driver ep93xxfb_driver = {
        .probe          = ep93xxfb_probe,
        .remove         = ep93xxfb_remove,
        .driver = {
                .name   = "ep93xx-fb",
        },
};
module_platform_driver(ep93xxfb_driver);

MODULE_DESCRIPTION("EP93XX Framebuffer Driver");
MODULE_ALIAS("platform:ep93xx-fb");
MODULE_AUTHOR("Ryan Mallon, "
              "H Hartley Sweeten <hsweeten@visionengravers.com");
MODULE_LICENSE("GPL");