diff options
Diffstat (limited to 'drivers/video/ramfb.c')
| -rw-r--r-- | drivers/video/ramfb.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/drivers/video/ramfb.c b/drivers/video/ramfb.c new file mode 100644 index 0000000000..3442e81b9e --- /dev/null +++ b/drivers/video/ramfb.c @@ -0,0 +1,191 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +// SPDX-FileCopyrightText: (C) 2022 Adrian Negreanu + +#define pr_fmt(fmt) "ramfb: " fmt + +#include <common.h> +#include <fb.h> +#include <fcntl.h> +#include <dma.h> +#include <init.h> +#include <unistd.h> +#include <sys/ioctl.h> +#include <fs.h> +#include <linux/qemu_fw_cfg.h> +#include <video/fourcc.h> + +struct ramfb { + int fd; + struct fb_info info; + dma_addr_t screen_dma; + struct fb_videomode mode; + u16 etcfb_select; +}; + +struct fw_cfg_etc_ramfb { + u64 addr; + u32 fourcc; + u32 flags; + u32 width; + u32 height; + u32 stride; +} __packed; + +static int fw_cfg_find_file(struct device *dev, int fd, const char *filename) +{ + size_t filename_len = strlen(filename); + ssize_t ret; + __be32 count; + int i; + + ioctl(fd, FW_CFG_SELECT, &(u16) { FW_CFG_FILE_DIR }); + + lseek(fd, 0, SEEK_SET); + + ret = read(fd, &count, sizeof(count)); + if (ret < 0) + return ret; + + for (i = 0; i < be32_to_cpu(count); i++) { + struct fw_cfg_file qfile; + + read(fd, &qfile, sizeof(qfile)); + + dev_dbg(dev, "enumerating file %s\n", qfile.name); + + if (memcmp(qfile.name, filename, filename_len)) + continue; + + return be16_to_cpu(qfile.select); + } + + return -ENOENT; +} + +static void ramfb_populate_modes(struct ramfb *ramfb) +{ + struct fb_info *info = &ramfb->info; + + ramfb->mode.name = "x8r8g8b8"; + info->xres = ramfb->mode.xres = 640; + info->yres = ramfb->mode.yres = 480; + + info->mode = &ramfb->mode; + info->bits_per_pixel = 32; + info->red = (struct fb_bitfield) {16, 8}; + info->green = (struct fb_bitfield) {8, 8}; + info->blue = (struct fb_bitfield) {0, 8}; + info->transp = (struct fb_bitfield) {0, 0}; +} + +static int ramfb_activate_var(struct fb_info *fbi) +{ + struct ramfb *ramfb = fbi->priv; + + if (fbi->screen_base) + dma_free_coherent(fbi->screen_base, ramfb->screen_dma, fbi->screen_size); + + fbi->screen_size = fbi->xres * fbi->yres * fbi->bits_per_pixel; + fbi->screen_base = dma_alloc_coherent(fbi->screen_size, &ramfb->screen_dma); + + return 0; +} + +static void ramfb_enable(struct fb_info *fbi) +{ + struct ramfb *ramfb = fbi->priv; + struct fw_cfg_etc_ramfb *etc_ramfb; + + etc_ramfb = dma_alloc(sizeof(*etc_ramfb)); + + etc_ramfb->addr = cpu_to_be64(ramfb->screen_dma); + etc_ramfb->fourcc = cpu_to_be32(DRM_FORMAT_XRGB8888); + etc_ramfb->flags = cpu_to_be32(0); + etc_ramfb->width = cpu_to_be32(fbi->xres); + etc_ramfb->height = cpu_to_be32(fbi->yres); + etc_ramfb->stride = cpu_to_be32(fbi->line_length); + + ioctl(ramfb->fd, FW_CFG_SELECT, &ramfb->etcfb_select); + + pwrite(ramfb->fd, etc_ramfb, sizeof(*etc_ramfb), 0); + + dma_free(etc_ramfb); +} + +static struct fb_ops ramfb_ops = { + .fb_activate_var = ramfb_activate_var, + .fb_enable = ramfb_enable, +}; + +static int ramfb_probe(struct device *parent_dev, int fd) +{ + int ret; + struct ramfb *ramfb; + struct fb_info *fbi; + + ret = -ENODEV; + + ramfb = xzalloc(sizeof(*ramfb)); + + ramfb->fd = fd; + + ret = fw_cfg_find_file(parent_dev, fd, "etc/ramfb"); + if (ret < 0) { + dev_dbg(parent_dev, "ramfb: fw_cfg (etc/ramfb) file not found\n"); + return -ENODEV; + } + + ramfb->etcfb_select = ret; + dev_dbg(parent_dev, "etc/ramfb file at slot 0x%x\n", ramfb->etcfb_select); + + fbi = &ramfb->info; + fbi->priv = ramfb; + fbi->fbops = &ramfb_ops; + fbi->dev.parent = parent_dev; + + ramfb_populate_modes(ramfb); + + ret = register_framebuffer(fbi); + if (ret < 0) { + dev_err(parent_dev, "Unable to register ramfb: %d\n", ret); + return ret; + } + + dev_info(parent_dev, "ramfb registered\n"); + + return 0; +} + +static int ramfb_driver_init(void) +{ + struct cdev *cdev; + int err = 0; + + for_each_cdev(cdev) { + int fd, ret; + + if (!strstarts(cdev->name, "fw_cfg")) + continue; + + fd = cdev_fdopen(cdev, O_RDWR); + if (fd < 0) { + err = fd; + continue; + } + + ret = ramfb_probe(cdev->dev, fd); + if (ret == 0) + continue; + if (ret != -ENODEV && ret != -ENXIO) + err = ret; + + close(fd); + } + + return err; +} +device_initcall(ramfb_driver_init); + +MODULE_AUTHOR("Adrian Negreanu <adrian.negreanu@nxp.com>"); +MODULE_DESCRIPTION("QEMU RamFB driver"); +MODULE_LICENSE("GPL v2"); |