root/drivers/video/fbdev/vt8500lcdfb.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/drivers/video/vt8500lcdfb.c
 *
 *  Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
 *
 * Based on skeletonfb.c and pxafb.c
 */

#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/errno.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/wait.h>
#include <video/of_display_timing.h>

#include "vt8500lcdfb.h"
#include "wmt_ge_rops.h"

#ifdef CONFIG_OF
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/memblock.h>
#endif


#define to_vt8500lcd_info(__info) container_of(__info, \
                                                struct vt8500lcd_info, fb)

static int vt8500lcd_set_par(struct fb_info *info)
{
        struct vt8500lcd_info *fbi = to_vt8500lcd_info(info);
        int reg_bpp = 5; /* 16bpp */
        int i;
        unsigned long control0;

        if (!fbi)
                return -EINVAL;

        if (info->var.bits_per_pixel <= 8) {
                /* palettized */
                info->var.red.offset    = 0;
                info->var.red.length    = info->var.bits_per_pixel;
                info->var.red.msb_right = 0;

                info->var.green.offset  = 0;
                info->var.green.length  = info->var.bits_per_pixel;
                info->var.green.msb_right = 0;

                info->var.blue.offset   = 0;
                info->var.blue.length   = info->var.bits_per_pixel;
                info->var.blue.msb_right = 0;

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

                info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
                info->fix.line_length = info->var.xres_virtual /
                                                (8/info->var.bits_per_pixel);
        } else {
                /* non-palettized */
                info->var.transp.offset = 0;
                info->var.transp.length = 0;
                info->var.transp.msb_right = 0;

                if (info->var.bits_per_pixel == 16) {
                        /* RGB565 */
                        info->var.red.offset = 11;
                        info->var.red.length = 5;
                        info->var.red.msb_right = 0;
                        info->var.green.offset = 5;
                        info->var.green.length = 6;
                        info->var.green.msb_right = 0;
                        info->var.blue.offset = 0;
                        info->var.blue.length = 5;
                        info->var.blue.msb_right = 0;
                } else {
                        /* Equal depths per channel */
                        info->var.red.offset = info->var.bits_per_pixel
                                                        * 2 / 3;
                        info->var.red.length = info->var.bits_per_pixel / 3;
                        info->var.red.msb_right = 0;
                        info->var.green.offset = info->var.bits_per_pixel / 3;
                        info->var.green.length = info->var.bits_per_pixel / 3;
                        info->var.green.msb_right = 0;
                        info->var.blue.offset = 0;
                        info->var.blue.length = info->var.bits_per_pixel / 3;
                        info->var.blue.msb_right = 0;
                }

                info->fix.visual = FB_VISUAL_TRUECOLOR;
                info->fix.line_length = info->var.bits_per_pixel > 16 ?
                                        info->var.xres_virtual << 2 :
                                        info->var.xres_virtual << 1;
        }

        for (i = 0; i < 8; i++) {
                if (bpp_values[i] == info->var.bits_per_pixel)
                        reg_bpp = i;
        }

        control0 = readl(fbi->regbase) & ~0xf;
        writel(0, fbi->regbase);
        while (readl(fbi->regbase + 0x38) & 0x10)
                /* wait */;
        writel((((info->var.hsync_len - 1) & 0x3f) << 26)
                | ((info->var.left_margin & 0xff) << 18)
                | (((info->var.xres - 1) & 0x3ff) << 8)
                | (info->var.right_margin & 0xff), fbi->regbase + 0x4);
        writel((((info->var.vsync_len - 1) & 0x3f) << 26)
                | ((info->var.upper_margin & 0xff) << 18)
                | (((info->var.yres - 1) & 0x3ff) << 8)
                | (info->var.lower_margin & 0xff), fbi->regbase + 0x8);
        writel((((info->var.yres - 1) & 0x400) << 2)
                | ((info->var.xres - 1) & 0x400), fbi->regbase + 0x10);
        writel(0x80000000, fbi->regbase + 0x20);
        writel(control0 | (reg_bpp << 1) | 0x100, fbi->regbase);

        return 0;
}

static inline u_int chan_to_field(u_int chan, struct fb_bitfield *bf)
{
        chan &= 0xffff;
        chan >>= 16 - bf->length;
        return chan << bf->offset;
}

static int vt8500lcd_setcolreg(unsigned regno, unsigned red, unsigned green,
                           unsigned blue, unsigned transp,
                           struct fb_info *info) {
        struct vt8500lcd_info *fbi = to_vt8500lcd_info(info);
        int ret = 1;
        unsigned int val;
        if (regno >= 256)
                return -EINVAL;

        if (info->var.grayscale)
                red = green = blue =
                        (19595 * red + 38470 * green + 7471 * blue) >> 16;

        switch (fbi->fb.fix.visual) {
        case FB_VISUAL_TRUECOLOR:
                if (regno < 16) {
                        u32 *pal = fbi->fb.pseudo_palette;

                        val  = chan_to_field(red, &fbi->fb.var.red);
                        val |= chan_to_field(green, &fbi->fb.var.green);
                        val |= chan_to_field(blue, &fbi->fb.var.blue);

                        pal[regno] = val;
                        ret = 0;
                }
                break;

        case FB_VISUAL_STATIC_PSEUDOCOLOR:
        case FB_VISUAL_PSEUDOCOLOR:
                writew((red & 0xf800)
                      | ((green >> 5) & 0x7e0)
                      | ((blue >> 11) & 0x1f),
                       fbi->palette_cpu + sizeof(u16) * regno);
                break;
        }

        return ret;
}

static int vt8500lcd_ioctl(struct fb_info *info, unsigned int cmd,
                         unsigned long arg)
{
        int ret = 0;
        struct vt8500lcd_info *fbi = to_vt8500lcd_info(info);

        if (cmd == FBIO_WAITFORVSYNC) {
                /* Unmask End of Frame interrupt */
                writel(0xffffffff ^ (1 << 3), fbi->regbase + 0x3c);
                ret = wait_event_interruptible_timeout(fbi->wait,
                        readl(fbi->regbase + 0x38) & (1 << 3), HZ / 10);
                /* Mask back to reduce unwanted interrupt traffic */
                writel(0xffffffff, fbi->regbase + 0x3c);
                if (ret < 0)
                        return ret;
                if (ret == 0)
                        return -ETIMEDOUT;
        }

        return ret;
}

static int vt8500lcd_pan_display(struct fb_var_screeninfo *var,
                                struct fb_info *info)
{
        unsigned pixlen = info->fix.line_length / info->var.xres_virtual;
        unsigned off = pixlen * var->xoffset
                      + info->fix.line_length * var->yoffset;
        struct vt8500lcd_info *fbi = to_vt8500lcd_info(info);

        writel((1 << 31)
             | (((info->var.xres_virtual - info->var.xres) * pixlen / 4) << 20)
             | (off >> 2), fbi->regbase + 0x20);
        return 0;
}

/*
 * vt8500lcd_blank():
 *      Blank the display by setting all palette values to zero.  Note,
 *      True Color modes do not really use the palette, so this will not
 *      blank the display in all modes.
 */
static int vt8500lcd_blank(int blank, struct fb_info *info)
{
        int i;

        switch (blank) {
        case FB_BLANK_POWERDOWN:
        case FB_BLANK_VSYNC_SUSPEND:
        case FB_BLANK_HSYNC_SUSPEND:
        case FB_BLANK_NORMAL:
                if (info->fix.visual == FB_VISUAL_PSEUDOCOLOR ||
                    info->fix.visual == FB_VISUAL_STATIC_PSEUDOCOLOR)
                        for (i = 0; i < 256; i++)
                                vt8500lcd_setcolreg(i, 0, 0, 0, 0, info);
                fallthrough;
        case FB_BLANK_UNBLANK:
                if (info->fix.visual == FB_VISUAL_PSEUDOCOLOR ||
                    info->fix.visual == FB_VISUAL_STATIC_PSEUDOCOLOR)
                        fb_set_cmap(&info->cmap, info);
        }
        return 0;
}

static const struct fb_ops vt8500lcd_ops = {
        .owner          = THIS_MODULE,
        __FB_DEFAULT_DMAMEM_OPS_RDWR,
        .fb_set_par     = vt8500lcd_set_par,
        .fb_setcolreg   = vt8500lcd_setcolreg,
        .fb_fillrect    = wmt_ge_fillrect,
        .fb_copyarea    = wmt_ge_copyarea,
        .fb_imageblit   = sys_imageblit,
        .fb_sync        = wmt_ge_sync,
        .fb_ioctl       = vt8500lcd_ioctl,
        .fb_pan_display = vt8500lcd_pan_display,
        .fb_blank       = vt8500lcd_blank,
        // .fb_mmap needs DMA mmap
};

static irqreturn_t vt8500lcd_handle_irq(int irq, void *dev_id)
{
        struct vt8500lcd_info *fbi = dev_id;

        if (readl(fbi->regbase + 0x38) & (1 << 3))
                wake_up_interruptible(&fbi->wait);

        writel(0xffffffff, fbi->regbase + 0x38);
        return IRQ_HANDLED;
}

static int vt8500lcd_probe(struct platform_device *pdev)
{
        struct vt8500lcd_info *fbi;
        struct resource *res;
        struct display_timings *disp_timing;
        void *addr;
        int irq, ret;

        struct fb_videomode     of_mode;
        u32                     bpp;
        dma_addr_t fb_mem_phys;
        unsigned long fb_mem_len;
        void *fb_mem_virt;

        ret = -ENOMEM;
        fbi = NULL;

        fbi = devm_kzalloc(&pdev->dev, sizeof(struct vt8500lcd_info)
                        + sizeof(u32) * 16, GFP_KERNEL);
        if (!fbi)
                return -ENOMEM;

        strcpy(fbi->fb.fix.id, "VT8500 LCD");

        fbi->fb.fix.type        = FB_TYPE_PACKED_PIXELS;
        fbi->fb.fix.xpanstep    = 0;
        fbi->fb.fix.ypanstep    = 1;
        fbi->fb.fix.ywrapstep   = 0;
        fbi->fb.fix.accel       = FB_ACCEL_NONE;

        fbi->fb.var.nonstd      = 0;
        fbi->fb.var.activate    = FB_ACTIVATE_NOW;
        fbi->fb.var.height      = -1;
        fbi->fb.var.width       = -1;
        fbi->fb.var.vmode       = FB_VMODE_NONINTERLACED;

        fbi->fb.fbops           = &vt8500lcd_ops;
        fbi->fb.flags           = FBINFO_HWACCEL_COPYAREA
                                | FBINFO_HWACCEL_FILLRECT
                                | FBINFO_HWACCEL_YPAN
                                | FBINFO_VIRTFB
                                | FBINFO_PARTIAL_PAN_OK;
        fbi->fb.node            = -1;

        addr = fbi;
        addr = addr + sizeof(struct vt8500lcd_info);
        fbi->fb.pseudo_palette  = addr;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (res == NULL) {
                dev_err(&pdev->dev, "no I/O memory resource defined\n");
                return -ENODEV;
        }

        res = request_mem_region(res->start, resource_size(res), "vt8500lcd");
        if (res == NULL) {
                dev_err(&pdev->dev, "failed to request I/O memory\n");
                return -EBUSY;
        }

        fbi->regbase = ioremap(res->start, resource_size(res));
        if (fbi->regbase == NULL) {
                dev_err(&pdev->dev, "failed to map I/O memory\n");
                ret = -EBUSY;
                goto failed_free_res;
        }

        disp_timing = of_get_display_timings(pdev->dev.of_node);
        if (!disp_timing) {
                ret = -EINVAL;
                goto failed_free_io;
        }

        ret = of_get_fb_videomode(pdev->dev.of_node, &of_mode,
                                                        OF_USE_NATIVE_MODE);
        if (ret)
                goto failed_free_io;

        ret = of_property_read_u32(pdev->dev.of_node, "bits-per-pixel", &bpp);
        if (ret)
                goto failed_free_io;

        /* try allocating the framebuffer */
        fb_mem_len = of_mode.xres * of_mode.yres * 2 * (bpp / 8);
        fb_mem_virt = dma_alloc_coherent(&pdev->dev, fb_mem_len, &fb_mem_phys,
                                GFP_KERNEL);
        if (!fb_mem_virt) {
                pr_err("%s: Failed to allocate framebuffer\n", __func__);
                ret = -ENOMEM;
                goto failed_free_io;
        }

        fbi->fb.fix.smem_start  = fb_mem_phys;
        fbi->fb.fix.smem_len    = fb_mem_len;
        fbi->fb.screen_buffer   = fb_mem_virt;

        fbi->palette_size       = PAGE_ALIGN(512);
        fbi->palette_cpu        = dma_alloc_coherent(&pdev->dev,
                                                     fbi->palette_size,
                                                     &fbi->palette_phys,
                                                     GFP_KERNEL);
        if (fbi->palette_cpu == NULL) {
                dev_err(&pdev->dev, "Failed to allocate palette buffer\n");
                ret = -ENOMEM;
                goto failed_free_mem_virt;
        }

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                ret = -ENODEV;
                goto failed_free_palette;
        }

        ret = request_irq(irq, vt8500lcd_handle_irq, 0, "LCD", fbi);
        if (ret) {
                dev_err(&pdev->dev, "request_irq failed: %d\n", ret);
                ret = -EBUSY;
                goto failed_free_palette;
        }

        init_waitqueue_head(&fbi->wait);

        if (fb_alloc_cmap(&fbi->fb.cmap, 256, 0) < 0) {
                dev_err(&pdev->dev, "Failed to allocate color map\n");
                ret = -ENOMEM;
                goto failed_free_irq;
        }

        fb_videomode_to_var(&fbi->fb.var, &of_mode);

        fbi->fb.var.xres_virtual        = of_mode.xres;
        fbi->fb.var.yres_virtual        = of_mode.yres * 2;
        fbi->fb.var.bits_per_pixel      = bpp;

        ret = vt8500lcd_set_par(&fbi->fb);
        if (ret) {
                dev_err(&pdev->dev, "Failed to set parameters\n");
                goto failed_free_cmap;
        }

        writel(fbi->fb.fix.smem_start >> 22, fbi->regbase + 0x1c);
        writel((fbi->palette_phys & 0xfffffe00) | 1, fbi->regbase + 0x18);

        platform_set_drvdata(pdev, fbi);

        ret = register_framebuffer(&fbi->fb);
        if (ret < 0) {
                dev_err(&pdev->dev,
                        "Failed to register framebuffer device: %d\n", ret);
                goto failed_free_cmap;
        }

        /*
         * Ok, now enable the LCD controller
         */
        writel(readl(fbi->regbase) | 1, fbi->regbase);

        return 0;

failed_free_cmap:
        if (fbi->fb.cmap.len)
                fb_dealloc_cmap(&fbi->fb.cmap);
failed_free_irq:
        free_irq(irq, fbi);
failed_free_palette:
        dma_free_coherent(&pdev->dev, fbi->palette_size,
                          fbi->palette_cpu, fbi->palette_phys);
failed_free_mem_virt:
        dma_free_coherent(&pdev->dev, fbi->fb.fix.smem_len,
                          fbi->fb.screen_buffer, fbi->fb.fix.smem_start);
failed_free_io:
        iounmap(fbi->regbase);
failed_free_res:
        release_mem_region(res->start, resource_size(res));
        return ret;
}

static void vt8500lcd_remove(struct platform_device *pdev)
{
        struct vt8500lcd_info *fbi = platform_get_drvdata(pdev);
        struct resource *res;
        int irq;

        unregister_framebuffer(&fbi->fb);

        writel(0, fbi->regbase);

        if (fbi->fb.cmap.len)
                fb_dealloc_cmap(&fbi->fb.cmap);

        irq = platform_get_irq(pdev, 0);
        free_irq(irq, fbi);

        dma_free_coherent(&pdev->dev, fbi->palette_size,
                          fbi->palette_cpu, fbi->palette_phys);

        iounmap(fbi->regbase);

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        release_mem_region(res->start, resource_size(res));
}

static const struct of_device_id via_dt_ids[] = {
        { .compatible = "via,vt8500-fb", },
        {}
};

static struct platform_driver vt8500lcd_driver = {
        .probe          = vt8500lcd_probe,
        .remove         = vt8500lcd_remove,
        .driver         = {
                .name   = "vt8500-lcd",
                .of_match_table = of_match_ptr(via_dt_ids),
        },
};

module_platform_driver(vt8500lcd_driver);

MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
MODULE_DESCRIPTION("LCD controller driver for VIA VT8500");
MODULE_LICENSE("GPL v2");
MODULE_DEVICE_TABLE(of, via_dt_ids);