Setting the NVMEM stride to 4 means we can't have nvmem cells pointing
at odd addresses. Linux sets it to 1 instead and handles reads at
unaligned addresses by splitting them up to aligned chunks. Copy over
the code to do the same. Unaligned writes remain illegal.
Signed-off-by: Ahmad Fatoum <ahmad@xxxxxx>
---
drivers/nvmem/bsec.c | 42 ++++++++++++++++++++++++++++++++++++++----
1 file changed, 38 insertions(+), 4 deletions(-)
diff --git a/drivers/nvmem/bsec.c b/drivers/nvmem/bsec.c
index d772d0b7af92..209c50dc7010 100644
--- a/drivers/nvmem/bsec.c
+++ b/drivers/nvmem/bsec.c
@@ -77,15 +77,49 @@ static int stm32_bsec_write(struct device_d *dev, int offset,
{
struct bsec_priv *priv = dev->parent->priv;
+ /* Allow only writing complete 32-bits aligned words */
+ if ((bytes % 4) || (offset % 4))
+ return -EINVAL;
+
return regmap_bulk_write(priv->map, offset, val, bytes);
}
static int stm32_bsec_read(struct device_d *dev, int offset,
- void *val, int bytes)
+ void *buf, int bytes)
{
struct bsec_priv *priv = dev->parent->priv;
+ u32 roffset, rbytes, val;
+ u8 *buf8 = buf, *val8 = (u8 *)&val;
+ int i, j = 0, ret, skip_bytes, size;
+
+ /* Round unaligned access to 32-bits */
+ roffset = rounddown(offset, 4);
+ skip_bytes = offset & 0x3;
+ rbytes = roundup(bytes + skip_bytes, 4);
+
+ if (roffset + rbytes > priv->config.size)
+ return -EINVAL;
+
+ for (i = roffset; i < roffset + rbytes; i += 4) {
+ ret = regmap_bulk_read(priv->map, i, &val, 4);
+ if (ret) {
+ dev_err(dev, "Can't read data%d (%d)\n", i, ret);
+ return ret;
+ }
+
+ /* skip first bytes in case of unaligned read */
+ if (skip_bytes)
+ size = min(bytes, 4 - skip_bytes);
+ else
+ size = min(bytes, 4);
+
+ memcpy(&buf8[j], &val8[skip_bytes], size);
+ bytes -= size;
+ j += size;
+ skip_bytes = 0;
+ }
- return regmap_bulk_read(priv->map, offset, val, bytes);
+ return 0;
}
static const struct nvmem_bus stm32_bsec_nvmem_bus = {
@@ -185,8 +219,8 @@ static int stm32_bsec_probe(struct device_d *dev)
priv->config.name = "stm32-bsec";
priv->config.dev = dev;
- priv->config.stride = 4;
- priv->config.word_size = 4;
+ priv->config.stride = 1;
+ priv->config.word_size = 1;
priv->config.size = data->num_regs;
priv->config.bus = &stm32_bsec_nvmem_bus;
dev->priv = priv;
--
2.20.1
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