Re: [PATCH v15 02/11] fw_cfg: add a public uapi header

[Michael S. Tsirkin]

On Thu, Feb 15, 2018 at 10:33:03PM +0100, Marc-André Lureau wrote:
> Create a common header file for well-known values and structures to be
> shared by the Linux kernel with qemu or other projects.
> 
> It is based from qemu/docs/specs/fw_cfg.txt which references
> qemu/include/hw/nvram/fw_cfg_keys.h "for the most up-to-date and
> authoritative list" & vmcoreinfo.txt. Those files don't have an
> explicit license, but qemu/hw/nvram/fw_cfg.c is BSD-license, so
> Michael S. Tsirkin suggested to use the same license.
> 
> The patch intentionally left out DMA & vmcoreinfo structures &
> defines, which are added in the commits making usage of it.
> 
> Suggested-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@xxxxxxxxxx>
> 
> ---
> 
> The related qemu patch making use of it, to be submitted:
> https://github.com/elmarco/qemu/commit/4884fc9e9c4c4467a371e5a40f3181239e1b70f5
> ---
>  MAINTAINERS                    |  1 +
>  drivers/firmware/qemu_fw_cfg.c | 22 ++------------
>  include/uapi/linux/fw_cfg.h    | 66 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 69 insertions(+), 20 deletions(-)
>  create mode 100644 include/uapi/linux/fw_cfg.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 3bdc260e36b7..a66b65f62811 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11352,6 +11352,7 @@ M:	"Michael S. Tsirkin" <mst@xxxxxxxxxx>
>  L:	qemu-devel@xxxxxxxxxx
>  S:	Maintained
>  F:	drivers/firmware/qemu_fw_cfg.c
> +F:	include/uapi/linux/fw_cfg.h
>  
>  QIB DRIVER
>  M:	Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>

Why fw_cfg.h and not qemu_fw_cfg.h ? fw_cfg.h seems too generic.

> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> index a41b572eeeb1..42601a3eaed5 100644
> --- a/drivers/firmware/qemu_fw_cfg.c
> +++ b/drivers/firmware/qemu_fw_cfg.c
> @@ -32,30 +32,12 @@
>  #include <linux/slab.h>
>  #include <linux/io.h>
>  #include <linux/ioport.h>
> +#include <uapi/linux/fw_cfg.h>
>  
>  MODULE_AUTHOR("Gabriel L. Somlo <somlo@xxxxxxx>");
>  MODULE_DESCRIPTION("QEMU fw_cfg sysfs support");
>  MODULE_LICENSE("GPL");
>  
> -/* selector key values for "well-known" fw_cfg entries */
> -#define FW_CFG_SIGNATURE  0x00
> -#define FW_CFG_ID         0x01
> -#define FW_CFG_FILE_DIR   0x19
> -
> -/* size in bytes of fw_cfg signature */
> -#define FW_CFG_SIG_SIZE 4
> -
> -/* fw_cfg "file name" is up to 56 characters (including terminating nul) */
> -#define FW_CFG_MAX_FILE_PATH 56
> -
> -/* fw_cfg file directory entry type */
> -struct fw_cfg_file {
> -	u32 size;
> -	u16 select;
> -	u16 reserved;
> -	char name[FW_CFG_MAX_FILE_PATH];
> -};
> -
>  /* fw_cfg device i/o register addresses */
>  static bool fw_cfg_is_mmio;
>  static phys_addr_t fw_cfg_p_base;
> @@ -597,7 +579,7 @@ MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match);
>  
>  #ifdef CONFIG_ACPI
>  static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = {
> -	{ "QEMU0002", },
> +	{ FW_CFG_ACPI_DEVICE_ID, },
>  	{},
>  };
>  MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match);
> diff --git a/include/uapi/linux/fw_cfg.h b/include/uapi/linux/fw_cfg.h
> new file mode 100644
> index 000000000000..c698ac3812f6
> --- /dev/null
> +++ b/include/uapi/linux/fw_cfg.h
> @@ -0,0 +1,66 @@
> +/* SPDX-License-Identifier: BSD-3-Clause */
> +#ifndef _LINUX_FW_CFG_H
> +#define _LINUX_FW_CFG_H
> +
> +#include <linux/types.h>
> +
> +#define FW_CFG_ACPI_DEVICE_ID	"QEMU0002"
> +
> +/* selector key values for "well-known" fw_cfg entries */
> +#define FW_CFG_SIGNATURE	0x00
> +#define FW_CFG_ID		0x01
> +#define FW_CFG_UUID		0x02
> +#define FW_CFG_RAM_SIZE		0x03
> +#define FW_CFG_NOGRAPHIC	0x04
> +#define FW_CFG_NB_CPUS		0x05
> +#define FW_CFG_MACHINE_ID	0x06
> +#define FW_CFG_KERNEL_ADDR	0x07
> +#define FW_CFG_KERNEL_SIZE	0x08
> +#define FW_CFG_KERNEL_CMDLINE	0x09
> +#define FW_CFG_INITRD_ADDR	0x0a
> +#define FW_CFG_INITRD_SIZE	0x0b
> +#define FW_CFG_BOOT_DEVICE	0x0c
> +#define FW_CFG_NUMA		0x0d
> +#define FW_CFG_BOOT_MENU	0x0e
> +#define FW_CFG_MAX_CPUS		0x0f
> +#define FW_CFG_KERNEL_ENTRY	0x10
> +#define FW_CFG_KERNEL_DATA	0x11
> +#define FW_CFG_INITRD_DATA	0x12
> +#define FW_CFG_CMDLINE_ADDR	0x13
> +#define FW_CFG_CMDLINE_SIZE	0x14
> +#define FW_CFG_CMDLINE_DATA	0x15
> +#define FW_CFG_SETUP_ADDR	0x16
> +#define FW_CFG_SETUP_SIZE	0x17
> +#define FW_CFG_SETUP_DATA	0x18
> +#define FW_CFG_FILE_DIR		0x19
> +
> +#define FW_CFG_FILE_FIRST	0x20
> +#define FW_CFG_FILE_SLOTS_MIN	0x10
> +
> +#define FW_CFG_WRITE_CHANNEL	0x4000
> +#define FW_CFG_ARCH_LOCAL	0x8000
> +#define FW_CFG_ENTRY_MASK	(~(FW_CFG_WRITE_CHANNEL | FW_CFG_ARCH_LOCAL))
> +
> +#define FW_CFG_INVALID		0xffff
> +
> +/* width in bytes of fw_cfg control register */
> +#define FW_CFG_CTL_SIZE		0x02
> +
> +/* fw_cfg "file name" is up to 56 characters (including terminating nul) */
> +#define FW_CFG_MAX_FILE_PATH	56
> +
> +/* size in bytes of fw_cfg signature */
> +#define FW_CFG_SIG_SIZE 4
> +
> +/* FW_CFG_ID bits */
> +#define FW_CFG_VERSION		0x01
> +
> +/* fw_cfg file directory entry type */
> +struct fw_cfg_file {
> +	__be32 size;
> +	__be16 select;
> +	__u16 reserved;
> +	char name[FW_CFG_MAX_FILE_PATH];
> +};
> +
> +#endif
> -- 
> 2.16.1.73.g5832b7e9f2