From: Chen-Yu Tsai <wens@kernel.org>
To: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
Maxime Ripard <maxime.ripard@bootlin.com>
Cc: linux-sunxi@googlegroups.com, Chen-Yu Tsai <wens@csie.org>,
linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 4/6] nvmem: sunxi_sid: Read out data in native format
Date: Mon, 18 Mar 2019 15:33:52 +0800 [thread overview]
Message-ID: <20190318073354.12151-5-wens@kernel.org> (raw)
In-Reply-To: <20190318073354.12151-1-wens@kernel.org>
From: Chen-Yu Tsai <wens@csie.org>
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>
---
drivers/nvmem/sunxi_sid.c | 23 +----------------------
1 file changed, 1 insertion(+), 22 deletions(-)
diff --git a/drivers/nvmem/sunxi_sid.c b/drivers/nvmem/sunxi_sid.c
index 75c1f48cb3d0..14c114620ed6 100644
--- a/drivers/nvmem/sunxi_sid.c
+++ b/drivers/nvmem/sunxi_sid.c
@@ -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;
}
--
2.20.1
next prev parent reply other threads:[~2019-03-18 7:34 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-18 7:33 [PATCH 0/6] nvmem: sunxi_sid: native format and A83T/H5 support Chen-Yu Tsai
2019-03-18 7:33 ` [PATCH 1/6] nvmem: sunxi_sid: Read out SID for randomness without looping Chen-Yu Tsai
2019-03-18 7:33 ` [PATCH 2/6] nvmem: sunxi_sid: Optimize register read-out method Chen-Yu Tsai
2019-03-18 7:33 ` [PATCH 3/6] nvmem: sunxi_sid: Dynamically allocate nvmem_config structure Chen-Yu Tsai
2019-03-18 7:33 ` Chen-Yu Tsai [this message]
2019-03-18 8:42 ` [PATCH 4/6] nvmem: sunxi_sid: Read out data in native format Maxime Ripard
2019-03-18 8:45 ` Chen-Yu Tsai
2019-03-18 8:57 ` Maxime Ripard
2019-03-18 9:09 ` Chen-Yu Tsai
2019-03-18 9:25 ` Maxime Ripard
2019-03-18 7:33 ` [PATCH 5/6] nvmem: sunxi_sid: Support SID on A83T and H5 Chen-Yu Tsai
2019-03-18 7:33 ` [PATCH 6/6] ARM: dts: sunxi: h3/h5: Add device node for SID Chen-Yu Tsai
2019-03-19 1:55 ` [linux-sunxi] " Samuel Holland
2019-03-19 3:17 ` Chen-Yu Tsai
2019-03-20 14:25 ` [PATCH 0/6] nvmem: sunxi_sid: native format and A83T/H5 support Srinivas Kandagatla
2019-03-21 9:06 ` Chen-Yu Tsai
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