Re: [PATCHv2 26/28] firmware: allow firmware files to be built into kernel image

From: Rusty Russell
Date: Fri May 30 2008 - 01:09:18 EST


On Sunday 25 May 2008 20:23:56 David Woodhouse wrote:
> Some drivers have their own hacks to bypass the kernel's firmware loader
> and build their firmware into the kernel; this renders those unnecessary.
>
> Other drivers don't use the firmware loader at all, because they always
> want the firmware to be available. This allows them to start using the
> firmware loader.
>
> A third set of drivers already use the firmware loader, but can't be
> used without help from userspace, which sometimes requires an initrd.
> This allows them to work in a static kernel.
>
> Signed-off-by: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
> ---
> drivers/base/firmware_class.c | 33 +++++++++++++++++++++++++++++++--
> include/asm-generic/vmlinux.lds.h | 7 +++++++
> include/linux/firmware.h | 21 +++++++++++++++++++++
> 3 files changed, 59 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
> index 264b3a2..c09f060 100644
> --- a/drivers/base/firmware_class.c
> +++ b/drivers/base/firmware_class.c
> @@ -49,6 +49,14 @@ struct firmware_priv {
> struct timer_list timeout;
> };
>
> +#ifdef CONFIG_FW_LOADER
> +extern struct builtin_fw __start_builtin_fw[];
> +extern struct builtin_fw __end_builtin_fw[];
> +#else /* Module case. Avoid ifdefs later; it'll all optimise out */
> +static struct builtin_fw *__start_builtin_fw = NULL;
> +static struct builtin_fw *__end_builtin_fw = NULL;
> +#endif
> +
> static void
> fw_load_abort(struct firmware_priv *fw_priv)
> {
> @@ -391,13 +399,12 @@ _request_firmware(const struct firmware **firmware_p,
> const char *name, struct device *f_dev;
> struct firmware_priv *fw_priv;
> struct firmware *firmware;
> + struct builtin_fw *builtin;
> int retval;
>
> if (!firmware_p)
> return -EINVAL;
>
> - printk(KERN_INFO "firmware: requesting %s\n", name);
> -
> *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
> if (!firmware) {
> printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
> @@ -406,6 +413,20 @@ _request_firmware(const struct firmware **firmware_p,
> const char *name, goto out;
> }
>
> + for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
> + builtin++) {
> + if (strcmp(name, builtin->name))
> + continue;
> + printk(KERN_INFO "firmware: using built-in firmware %s\n",
> + name);
> + firmware->size = builtin->size;
> + firmware->data = builtin->data;
> + return 0;
> + }
> +
> + if (uevent)
> + printk(KERN_INFO "firmware: requesting %s\n", name);
> +
> retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
> if (retval)
> goto error_kfree_fw;
> @@ -473,8 +494,16 @@ request_firmware(const struct firmware **firmware_p,
> const char *name, void
> release_firmware(const struct firmware *fw)
> {
> + struct builtin_fw *builtin;
> +
> if (fw) {
> + for (builtin = __start_builtin_fw; builtin != __end_builtin_fw;
> + builtin++) {
> + if (fw->data == builtin->data)
> + goto free_fw;
> + }
> vfree(fw->data);
> + free_fw:
> kfree(fw);
> }
> }
> diff --git a/include/asm-generic/vmlinux.lds.h
> b/include/asm-generic/vmlinux.lds.h index f054778..8d71a40 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -86,6 +86,13 @@
> VMLINUX_SYMBOL(__end_pci_fixups_resume) = .; \
> } \
> \
> + /* Built-in firmware blobs */ \
> + .builtin_fw : AT(ADDR(.builtin_fw) - LOAD_OFFSET) { \
> + VMLINUX_SYMBOL(__start_builtin_fw) = .; \
> + *(.builtin_fw) \
> + VMLINUX_SYMBOL(__end_builtin_fw) = .; \
> + } \
> + \
> /* RapidIO route ops */ \
> .rio_route : AT(ADDR(.rio_route) - LOAD_OFFSET) { \
> VMLINUX_SYMBOL(__start_rio_route_ops) = .; \
> diff --git a/include/linux/firmware.h b/include/linux/firmware.h
> index 5e73f3f..279eaad 100644
> --- a/include/linux/firmware.h
> +++ b/include/linux/firmware.h
> @@ -1,7 +1,10 @@
> #ifndef _LINUX_FIRMWARE_H
> #define _LINUX_FIRMWARE_H
> +
> #include <linux/module.h>
> #include <linux/types.h>
> +#include <linux/compiler.h>
> +
> #define FIRMWARE_NAME_MAX 30
> #define FW_ACTION_NOHOTPLUG 0
> #define FW_ACTION_HOTPLUG 1
> @@ -13,6 +16,24 @@ struct firmware {
>
> struct device;
>
> +struct builtin_fw {
> + char *name;
> + void *data;
> + unsigned long size;
> +};
> +
> +/* We have to play tricks here much like stringify() to get the
> + __COUNTER__ macro to be expanded as we want it */
> +#define __fw_concat1(x,y) x##y
> +#define __fw_concat(x,y) __fw_concat1(x,y)

Hmm, linux/module.h does this too, perhaps some enthusiast can implement
__concat() and use it everywhere.

Cheers,
Rusty.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/