Re: [PATCH 2/4] thermal: imx: Add support for reading OCOTP through nvmem

From: Srinivas Kandagatla
Date: Fri Jul 14 2017 - 04:50:05 EST




On 12/07/17 07:36, Shawn Guo wrote:
+static int nvmem_cell_read_u32(struct device* dev, const char *cell_id, u32 *val)
+{
+ struct nvmem_cell *cell;
+ void *buf;
+ size_t len;
+
+ cell = nvmem_cell_get(dev, cell_id);
+ if (IS_ERR(cell))
+ return PTR_ERR(cell);
+
+ buf = nvmem_cell_read(cell, &len);
+ if (IS_ERR(buf)) {
+ nvmem_cell_put(cell);
+ return PTR_ERR(buf);
+ }
+ if (len != sizeof(*val)) {
+ kfree(buf);
+ nvmem_cell_put(cell);
+ return -EINVAL;
+ }
+ memcpy(val, buf, sizeof(*val));

This can overflow the memory allocated to val, we should be careful here not to do so.
limit this to sizeof(u32) should be good. Also add some sanity checks to make sure that len is atleast 4 bytes.


+
+ kfree(buf);
+ nvmem_cell_put(cell);
+ return 0;
+}
The function looks nothing IMX specific, and could be a nvmem core
function?

@Srinivas, thoughts?
Yep, this function looks generic, can be moved to nvmem layer.

Thanks,
srini