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// 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");
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