Messages in this thread | | | From | Bjørn Mork <> | Subject | Re: [RFC V1 5/8] smi2021: Add smi2021_video.c | Date | Mon, 18 Mar 2013 09:58:32 +0100 |
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Hans Verkuil <hverkuil@xs4all.nl> writes:
>> +/* >> + * >> + * The device delivers data in chunks of 0x400 bytes. >> + * The four first bytes is a magic header to identify the chunks. >> + * 0xaa 0xaa 0x00 0x00 = saa7113 Active Video Data >> + * 0xaa 0xaa 0x00 0x01 = PCM - 24Bit 2 Channel audio data >> + */ >> +static void process_packet(struct smi2021_dev *dev, u8 *p, int len) >> +{ >> + int i; >> + u32 *header; >> + >> + if (len % 0x400 != 0) { >> + printk_ratelimited(KERN_INFO "smi2021::%s: len: %d\n", >> + __func__, len); >> + return; >> + } >> + >> + for (i = 0; i < len; i += 0x400) { >> + header = (u32 *)(p + i); >> + switch (__cpu_to_be32(*header)) { > > That's not right. You probably mean __be32_to_cpu, that makes more sense. > >> + case 0xaaaa0000: { >> + parse_video(dev, p+i+4, 0x400-4); >> + break; >> + } >> + case 0xaaaa0001: { >> + smi2021_audio(dev, p+i+4, 0x400-4); >> + break; >> + }
This could be just me, but I would have done it like this to take advantage of compile time constant conversions (and also dropping the noisy extra {}s):
switch (*header) { case cpu_to_be32(0xaaaa0000): parse_video(dev, p+i+4, 0x400-4); break; case cpu_to_be32(0xaaaa0001): smi2021_audio(dev, p+i+4, 0x400-4); break; ..
From the name of the function I assume the difference may actually be measurable here if this runs for every processed packet.
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