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SubjectRe: [PATCH v4 2/3] media: rc: introduce BPF_PROG_LIRC_MODE2
On Fri, May 18, 2018 at 03:07:29PM +0100, Sean Young wrote:
> Add support for BPF_PROG_LIRC_MODE2. This type of BPF program can call
> rc_keydown() to reported decoded IR scancodes, or rc_repeat() to report
> that the last key should be repeated.
>
> The bpf program can be attached to using the bpf(BPF_PROG_ATTACH) syscall;
> the target_fd must be the /dev/lircN device.
>
> Signed-off-by: Sean Young <sean@mess.org>
...
> enum bpf_attach_type {
> @@ -158,6 +159,7 @@ enum bpf_attach_type {
> BPF_CGROUP_INET6_CONNECT,
> BPF_CGROUP_INET4_POST_BIND,
> BPF_CGROUP_INET6_POST_BIND,
> + BPF_LIRC_MODE2,
> __MAX_BPF_ATTACH_TYPE
> };
>
> @@ -1902,6 +1904,53 @@ union bpf_attr {
> * egress otherwise). This is the only flag supported for now.
> * Return
> * **SK_PASS** on success, or **SK_DROP** on error.
> + *
> + * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
> + * Description
> + * This helper is used in programs implementing IR decoding, to
> + * report a successfully decoded key press with *scancode*,
> + * *toggle* value in the given *protocol*. The scancode will be
> + * translated to a keycode using the rc keymap, and reported as
> + * an input key down event. After a period a key up event is
> + * generated. This period can be extended by calling either
> + * **bpf_rc_keydown** () with the same values, or calling
> + * **bpf_rc_repeat** ().
> + *
> + * Some protocols include a toggle bit, in case the button
> + * was released and pressed again between consecutive scancodes
> + *
> + * The *ctx* should point to the lirc sample as passed into
> + * the program.
> + *
> + * The *protocol* is the decoded protocol number (see
> + * **enum rc_proto** for some predefined values).
> + *
> + * This helper is only available is the kernel was compiled with
> + * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
> + * "**y**".
> + *
> + * Return
> + * 0
> + *
> + * int bpf_rc_repeat(void *ctx)
> + * Description
> + * This helper is used in programs implementing IR decoding, to
> + * report a successfully decoded repeat key message. This delays
> + * the generation of a key up event for previously generated
> + * key down event.
> + *
> + * Some IR protocols like NEC have a special IR message for
> + * repeating last button, for when a button is held down.
> + *
> + * The *ctx* should point to the lirc sample as passed into
> + * the program.
> + *
> + * This helper is only available is the kernel was compiled with
> + * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
> + * "**y**".

Hi Sean,

thank you for working on this. The patch set looks good to me.
I'd only ask to change above two helper names to something more specific.
Since BPF_PROG_TYPE_LIRC_MODE2 is the name of new prog type and kconfig.
May be bpf_lirc2_keydown() and bpf_lirc2_repeat() ?

> @@ -1576,6 +1577,8 @@ static int bpf_prog_attach(const union bpf_attr *attr)
> case BPF_SK_SKB_STREAM_PARSER:
> case BPF_SK_SKB_STREAM_VERDICT:
> return sockmap_get_from_fd(attr, BPF_PROG_TYPE_SK_SKB, true);
> + case BPF_LIRC_MODE2:
> + return rc_dev_prog_attach(attr);
...
> + case BPF_LIRC_MODE2:
> + return rc_dev_prog_detach(attr);

and similar rename for internal function names that go into bpf core.

Please add accumulated acks when you respin.

Thanks

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