nvmem: sunxi_sid: Read out data in native format (273a474e) · Commits · 戴 / test

Originally the SID e-fuses were thought to be in big-endian format. Later sources show that they are in fact native or little-endian. The most compelling evidence is the thermal sensor calibration data, which is a set of one to three 16-bit values. In native-endian they are in 16-bit cells with increasing offsets, whereas with big-endian they are in the wrong order, and a gap with no data will show if there are one or three cells. Switch to a native endian representation for the nvmem device. For the H3, the register read-out method was already returning data in native endian. This only affects the other SoCs. Signed-off-by:

Chen-Yu Tsai <wens@csie.org> Acked-by:

Maxime Ripard <maxime.ripard@bootlin.com> Signed-off-by:

Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvmem/sunxi_sid.c

+1 −22

Original line number	Diff line number	Diff line
		@@ -46,33 +46,12 @@ struct sunxi_sid {
		u32 value_offset;
		};

		/* We read the entire key, due to a 32 bit read alignment requirement. Since we
		* want to return the requested byte, this results in somewhat slower code and
		* uses 4 times more reads as needed but keeps code simpler. Since the SID is
		* only very rarely probed, this is not really an issue.
		*/
		static u8 sunxi_sid_read_byte(const struct sunxi_sid *sid,
		const unsigned int offset)
		{
		u32 sid_key;

		sid_key = ioread32be(sid->base + round_down(offset, 4));
		sid_key >>= (offset % 4) * 8;

		return sid_key; /* Only return the last byte */
		}

		static int sunxi_sid_read(void *context, unsigned int offset,
		void *val, size_t bytes)
		{
		struct sunxi_sid *sid = context;
		u8 *buf = val;

		/* Offset the read operation to the real position of SID */
		offset += sid->value_offset;

		while (bytes--)
		*buf++ = sunxi_sid_read_byte(sid, offset++);
		memcpy_fromio(val, sid->base + sid->value_offset + offset, bytes);

		return 0;
		}

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