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Commit 273a474e authored by Chen-Yu Tsai's avatar Chen-Yu Tsai Committed by Greg Kroah-Hartman
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nvmem: sunxi_sid: Read out data in native format 



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: default avatarChen-Yu Tsai <wens@csie.org>
Acked-by: default avatarMaxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: default avatarSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7fa5ad23

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;

}