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nvmem: sunxi_sid: Read out data in native format

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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>
This commit is contained in:
Chen-Yu Tsai 2019-04-13 11:32:52 +01:00 committed by Greg Kroah-Hartman
parent 7fa5ad23db
commit 273a474ee8
1 changed files with 1 additions and 22 deletions
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23
drivers/nvmem/sunxi_sid.c
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@ -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;
}