While we have FW_CFG support as file system, there is a number of keys that precede the keys in the file system, which can be useful in some scenarios.
Add support for QEMU -uuid, -kernel, -initrd, -append options as well as a /boot/qemu_fw_cfg script that continues booting according to the latter three options. Signed-off-by: Ahmad Fatoum <[email protected]> --- common/boards/Kconfig | 8 + common/boards/Makefile | 1 + common/boards/qemu/Makefile | 4 + .../defaultenv-qemu_fw_cfg/boot/qemu_fw_cfg | 12 + common/boards/qemu/fw_cfg.c | 208 ++++++++++++++++++ drivers/firmware/Kconfig | 1 + 6 files changed, 234 insertions(+) create mode 100644 common/boards/qemu/Makefile create mode 100755 common/boards/qemu/defaultenv-qemu_fw_cfg/boot/qemu_fw_cfg create mode 100644 common/boards/qemu/fw_cfg.c diff --git a/common/boards/Kconfig b/common/boards/Kconfig index 74947316954b..a9e1b75a7641 100644 --- a/common/boards/Kconfig +++ b/common/boards/Kconfig @@ -1,5 +1,13 @@ # SPDX-License-Identifier: GPL-2.0-only +config BOARD_QEMU + bool "Extra support for QEMU-emulated boards" if COMPILE_TEST + +config BOARD_QEMU_VIRT + bool + select OF_OVERLAY + select BOARD_QEMU + config BOARD_QEMU_VIRT bool select OF_OVERLAY diff --git a/common/boards/Makefile b/common/boards/Makefile index 058733522411..86d07e04a2ad 100644 --- a/common/boards/Makefile +++ b/common/boards/Makefile @@ -1,5 +1,6 @@ # SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_BOARD_QEMU) += qemu/ obj-$(CONFIG_BOARD_QEMU_VIRT) += qemu-virt/ obj-$(CONFIG_BOARD_PHYTEC_SOM_DETECTION) += phytec/ obj-$(CONFIG_BOARD_TQ) += tq/ diff --git a/common/boards/qemu/Makefile b/common/boards/qemu/Makefile new file mode 100644 index 000000000000..2ea91d194bfc --- /dev/null +++ b/common/boards/qemu/Makefile @@ -0,0 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0-only + +obj-$(CONFIG_QEMU_FW_CFG) += fw_cfg.o +bbenv-$(CONFIG_QEMU_FW_CFG) += defaultenv-qemu_fw_cfg diff --git a/common/boards/qemu/defaultenv-qemu_fw_cfg/boot/qemu_fw_cfg b/common/boards/qemu/defaultenv-qemu_fw_cfg/boot/qemu_fw_cfg new file mode 100755 index 000000000000..a3c12df67ff5 --- /dev/null +++ b/common/boards/qemu/defaultenv-qemu_fw_cfg/boot/qemu_fw_cfg @@ -0,0 +1,12 @@ +#!/bin/sh + +global.bootm.image=/dev/fw_cfg.kernel + +if [ -s /dev/fw_cfg.initrd ]; then + global.bootm.initrd=/dev/fw_cfg.initrd +fi + +if [ -s /dev/fw_cfg.cmdline ]; then + readf /dev/fw_cfg.initrd qemu_fw_cfg_cmdline + global linux.bootargs.dyn.qemu="${qemu_fw_cfg_cmdline}" +fi diff --git a/common/boards/qemu/fw_cfg.c b/common/boards/qemu/fw_cfg.c new file mode 100644 index 000000000000..d0900b2ab7c3 --- /dev/null +++ b/common/boards/qemu/fw_cfg.c @@ -0,0 +1,208 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Common QEMU fw_cfg board code */ + +#include <fs.h> +#include <init.h> +#include <driver.h> +#include <xfuncs.h> +#include <envfs.h> +#include <machine_id.h> +#include <barebox-info.h> +#include <linux/uuid.h> +#include <linux/qemu_fw_cfg.h> + +struct fw_cfg_cdev { + struct cdev cdev; + u16 size_selector; + u16 data_selector; + void *cache; + size_t cached_size; /* How many bytes from start are cached */ +}; + +static struct fw_cfg_cdev *to_fw_cfg_cdev(struct cdev *cdev) +{ + return container_of(cdev, struct fw_cfg_cdev, cdev); +} + +static int qemu_fw_cfg_read(int fd, u16 selector, void *buf, size_t size) +{ + ssize_t ret; + + ret = ioctl(fd, FW_CFG_SELECT, &selector); + if (ret || !buf) + return ret; + + ret = pread(fd, buf, size, 0); + return ret < 0 ? ret : 0; +} + +static ssize_t fw_cfg_cdev_read(struct cdev *cdev, void *buf, size_t count, + loff_t offset, ulong flags) +{ + struct fw_cfg_cdev *fcc = to_fw_cfg_cdev(cdev); + size_t end_pos = offset + count; + size_t to_read, to_copy; + int ret; + + /* Bounds check */ + if (offset >= cdev->size) + return 0; + + if (end_pos > cdev->size) + end_pos = cdev->size; + + count = end_pos - offset; + + /* Allocate cache on first read */ + if (!fcc->cache) { + fcc->cache = malloc(cdev->size); + if (!fcc->cache) + return -ENOMEM; + fcc->cached_size = 0; + } + + /* Extend cache if needed */ + if (end_pos > fcc->cached_size) { + int fd; + + to_read = end_pos - fcc->cached_size; + + fd = open("/dev/fw_cfg", O_RDWR); + if (fd < 0) + return fd; + + ret = qemu_fw_cfg_read(fd, fcc->data_selector, + fcc->cache + fcc->cached_size, to_read); + + close(fd); + + if (ret) + return ret; + + fcc->cached_size = end_pos; + } + + /* Copy from cache to user buffer */ + to_copy = count; + + if (buf) + memcpy(buf, fcc->cache + offset, to_copy); + + return to_copy; +} + +static int fw_cfg_cdev_mmap(struct cdev *cdev, void **map, int flags) +{ + struct fw_cfg_cdev *fcc = to_fw_cfg_cdev(cdev); + ssize_t ret; + + if (flags & PROT_WRITE) + return -EACCES; + + ret = fw_cfg_cdev_read(cdev, NULL, ~0, 0, 0); + if (ret == 0) + ret = -EINVAL; + if (ret < 0) + return ret; + + *map = fcc->cache; + + return PTR_ERR_OR_ZERO(*map); +} + +static int fw_cfg_cdev_flush(struct cdev *cdev) +{ + struct fw_cfg_cdev *fcc = to_fw_cfg_cdev(cdev); + + if (fcc->cache) { + free(fcc->cache); + fcc->cache = NULL; + fcc->cached_size = 0; + } + + return 0; +} + +static struct cdev_operations fw_cfg_cdev_ops = { + .read = fw_cfg_cdev_read, + .flush = fw_cfg_cdev_flush, + .memmap = fw_cfg_cdev_mmap, +}; + +static int fw_cfg_register_cdev(int fd, const char *name, + u16 size_selector, u16 data_selector) +{ + struct fw_cfg_cdev *fcc; + u32 size; + int ret; + + /* Read size upfront */ + ret = qemu_fw_cfg_read(fd, size_selector, &size, sizeof(size)); + if (!ret && !size) + ret = -ENOENT; + if (ret < 0) + return ret; + + fcc = xzalloc(sizeof(*fcc)); + fcc->size_selector = size_selector; + fcc->data_selector = data_selector; + fcc->cache = xzalloc(size); + fcc->cached_size = size; + + ret = qemu_fw_cfg_read(fd, data_selector, + fcc->cache, fcc->cached_size); + if (ret) + return ret; + + fcc->cdev.name = xstrdup(name); + fcc->cdev.size = size; + fcc->cdev.ops = &fw_cfg_cdev_ops; + + ret = devfs_create(&fcc->cdev); + if (ret < 0) { + free(fcc->cdev.name); + free(fcc); + return ret; + } + + return 0; +} + +static int qemu_fw_cfg_boot_init(void) +{ + struct { + const char prefix[16]; + uuid_t uuid; + } machine_hashable = { "qemubareboxuuid"}; + __always_unused size_t size; + int fd, ret; + + fd = open("/dev/fw_cfg", O_RDWR); + if (fd < 0) + return 0; + + /* Specified by -uuid. Zero by default */ + ret = qemu_fw_cfg_read(fd, FW_CFG_UUID, &machine_hashable.uuid, + sizeof(machine_hashable.uuid)); + if (!ret) { + barebox_set_product_uuid(&machine_hashable.uuid); + if (!machine_id_get_hashable(&size)) + machine_id_set_hashable(&machine_hashable, sizeof(machine_hashable)); + } + + /* Register fw_cfg cdevs */ + fw_cfg_register_cdev(fd, "fw_cfg.kernel", FW_CFG_KERNEL_SIZE, FW_CFG_KERNEL_DATA); + fw_cfg_register_cdev(fd, "fw_cfg.initrd", FW_CFG_INITRD_SIZE, FW_CFG_INITRD_DATA); + fw_cfg_register_cdev(fd, "fw_cfg.cmdline", FW_CFG_CMDLINE_SIZE, FW_CFG_CMDLINE_DATA); + + defaultenv_append_directory(defaultenv_qemu_fw_cfg); + + /* Reset cdev to beginning */ + ret = qemu_fw_cfg_read(fd, FW_CFG_SIGNATURE, NULL, 0); + if (ret) + return ret; + + close(fd); + return 0; +} +crypto_initcall(qemu_fw_cfg_boot_init); diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig index 649b80ac289c..d7bf1d78937a 100644 --- a/drivers/firmware/Kconfig +++ b/drivers/firmware/Kconfig @@ -45,6 +45,7 @@ config FIRMWARE_ZYNQ7000_FPGA config QEMU_FW_CFG bool "QEMU FW CFG interface" + select BOARD_QEMU help This driver exposes the QEMU FW CFG conduit as a single character device. -- 2.47.3
