Re: [PATCH v4 2/3] media: rc: introduce BPF_PROG_LIRC_MODE2
From: Alexei Starovoitov <hidden>
Date: 2018-05-25 20:45:18
Also in:
linux-media, lkml
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>
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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() ?
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@@ -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);
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+ 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