Hi Shunqian,
Sorry for delay in reply, I was on Holidays..
Thanks for testing.
On 31/07/15 10:27, Shunqian Zheng wrote:
>
> 1. Without the following diff, `hexdump
> /sys/bus/nvmem/devices/rockchip-efuse0/nvmem` is wrong with "INVALID
> ARGUMENT":
>
> +++ b/drivers/nvmem/core.c
> @@ -67,7 +67,7 @@ static ssize_t bin_attr_nvmem_read(struct file *filp,
> struct kobject *kobj,
> int rc;
>
> /* Stop the user from reading */
> - if (pos > nvmem->size)
> + if (pos > nvmem->size - 1)
> return 0;
Yes, this should have been something like this
- if (pos > nvmem->size)
+ if (pos >= nvmem->size)
return 0;
We can send a fix on top of v9 once its merged.
>
> if (pos + count > nvmem->size)
>
> RK3288-efuse has 32 x 8bit regs, in dts "reg = <0xffb40000 0x20>;"
> Here is the message dump from nvmem_device:
> [ 2.158314] nvmem:
> [ 2.158314] name (null)
> [ 2.158314] stride 1
> [ 2.158314] word_size 1
> [ 2.158314] ncells 0
> [ 2.158314] id 0
> [ 2.158314] users 0
> [ 2.158314] size 32
> [ 2.158314] read_only 0
>
> Do you think there is a leak or I'm messing up ?
>
> 2. About the read operation, eFuse data can be read during device
> probe() and cached, OR,
> read from eFuse when needed every time. I prefer the second one but
> then, the clock of eFuse may be
> gated. So before/after reading I have to enable/disable clk like :
> devm_clk_get(dev, "hclk_efuse256");
> The trouble is I can't find a way to get the "dev" hander in :
> static int rockchip_efuse_read(void *context, const void
> *reg, size_t reg_size, void *val, size_t val_size)
> I am appreciated if you can give some advice.
May be you should use regmap_init_mmio_clk() instead of
regmap_init_mmio() it will take care of clks.
> Or, do you think it's reasonable to add hooks before/after read in
> nvmem/core.c like :
> + before_read(dev, ...);
> rc = regmap_raw_read(nvmem->regmap, pos, buf, count);
> + after_read(dev, ...);
>
> 3. In the /sys/bus/nvmem/devices/rockchip-efuse0/, there are files:
> /sys/devices/platform/ffb40000.efuse/rockchip-efuse0 # ls
> nvmem of_node power subsystem uevent
> Do you have a plan to add the nvmem consumers to /sys/ in nvmem
> framework?
yes, Am waiting for the framework to be merged, I have plans to add this
feature.
> For example, in dts defined the "cpu_leakage":
> efuse: efuse at ffb40000 {
> compatible = "rockchip,rk3x-efuse";
> reg = <0xffb40000 0x20>;
> #address-cells = <1>;
> #size-cells = <1>;
> clocks = <&cru PCLK_EFUSE256>;
> clock-names = "pclk_efuse_256";
>
> cpu_leakage: cpu_leakage {
> reg = <0x17 0x1>;
> };
> };
> Then nvmem exposes the "cpu_leakage" file in /sys which can be
> read/write.
--srini
