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From 0ab09d651b5858f9bc7d5f74e725334a661828e0 Mon Sep 17 00:00:00 2001
From: Icenowy Zheng <icenowy@aosc.io>
Date: Fri, 9 Mar 2018 14:47:17 +0000
Subject: nvmem: sunxi-sid: fix H3 SID controller support
It seems that doing some operation will make the value pre-read on H3
SID controller wrong again, so all operation should be performed by
register.
Change the SID reading to use register only.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/nvmem/sunxi_sid.c | 71 +++++++++++++++++++++++++++++++++--------------
1 file changed, 50 insertions(+), 21 deletions(-)
diff --git a/drivers/nvmem/sunxi_sid.c b/drivers/nvmem/sunxi_sid.c
index 99bd54d..26bb637 100644
--- a/drivers/nvmem/sunxi_sid.c
+++ b/drivers/nvmem/sunxi_sid.c
@@ -85,13 +85,14 @@ static int sunxi_sid_read(void *context, unsigned int offset,
}
static int sun8i_sid_register_readout(const struct sunxi_sid *sid,
- const unsigned int word)
+ const unsigned int offset,
+ u32 *out)
{
u32 reg_val;
int ret;
/* Set word, lock access, and set read command */
- reg_val = (word & SUN8I_SID_OFFSET_MASK)
+ reg_val = (offset & SUN8I_SID_OFFSET_MASK)
<< SUN8I_SID_OFFSET_SHIFT;
reg_val |= SUN8I_SID_OP_LOCK | SUN8I_SID_READ;
writel(reg_val, sid->base + SUN8I_SID_PRCTL);
@@ -101,7 +102,49 @@ static int sun8i_sid_register_readout(const struct sunxi_sid *sid,
if (ret)
return ret;
+ if (out)
+ *out = readl(sid->base + SUN8I_SID_RDKEY);
+
writel(0, sid->base + SUN8I_SID_PRCTL);
+
+ return 0;
+}
+
+/*
+ * On Allwinner H3, the value on the 0x200 offset of the SID controller seems
+ * to be not reliable at all.
+ * Read by the registers instead.
+ */
+static int sun8i_sid_read_byte_by_reg(const struct sunxi_sid *sid,
+ const unsigned int offset,
+ u8 *out)
+{
+ u32 word;
+ int ret;
+
+ ret = sun8i_sid_register_readout(sid, offset & ~0x03, &word);
+
+ if (ret)
+ return ret;
+
+ *out = (word >> ((offset & 0x3) * 8)) & 0xff;
+
+ return 0;
+}
+
+static int sun8i_sid_read_by_reg(void *context, unsigned int offset,
+ void *val, size_t bytes)
+{
+ struct sunxi_sid *sid = context;
+ u8 *buf = val;
+ int ret;
+
+ while (bytes--) {
+ ret = sun8i_sid_read_byte_by_reg(sid, offset++, buf++);
+ if (ret)
+ return ret;
+ }
+
return 0;
}
@@ -131,26 +174,12 @@ static int sunxi_sid_probe(struct platform_device *pdev)
size = cfg->size;
- if (cfg->need_register_readout) {
- /*
- * H3's SID controller have a bug that the value at 0x200
- * offset is not the correct value when the hardware is reseted.
- * However, after doing a register-based read operation, the
- * value become right.
- * Do a full read operation here, but ignore its value
- * (as it's more fast to read by direct MMIO value than
- * with registers)
- */
- for (i = 0; i < (size >> 2); i++) {
- ret = sun8i_sid_register_readout(sid, i);
- if (ret)
- return ret;
- }
- }
-
econfig.size = size;
econfig.dev = dev;
- econfig.reg_read = sunxi_sid_read;
+ if (cfg->need_register_readout)
+ econfig.reg_read = sun8i_sid_read_by_reg;
+ else
+ econfig.reg_read = sunxi_sid_read;
econfig.priv = sid;
nvmem = nvmem_register(&econfig);
if (IS_ERR(nvmem))
@@ -163,7 +192,7 @@ static int sunxi_sid_probe(struct platform_device *pdev)
}
for (i = 0; i < size; i++)
- randomness[i] = sunxi_sid_read_byte(sid, i);
+ econfig.reg_read(sid, i, &randomness[i], 1);
add_device_randomness(randomness, size);
kfree(randomness);
--
cgit v1.1
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