Srinivas, El 26/10/15 a las 10:37, Srinivas Kandagatla escribió: > > > On 24/10/15 23:04, Joachim Eastwood wrote: >> Hi Ariel, >> >> On 19 October 2015 at 19:32, Ariel D'Alessandro >> <ariel@xxxxxxxxxxxxxxxxxxxx> wrote: >>> This commit adds support for NXP LPC18xx EEPROM memory found in NXP >>> LPC185x/3x and LPC435x/3x/2x/1x devices. >>> >>> EEPROM size is 16384 bytes and it can be entirely read and >>> written/erased with 1 word (4 bytes) granularity. The last page >>> (128 bytes) contains the EEPROM initialization data and is not writable. >>> >>> Erase/program time is less than 3ms. The EEPROM device requires a >>> ~1500 kHz clock (min 800 kHz, max 1600 kHz) that is generated dividing >>> the system bus clock by the division factor, contained in the divider >>> register (minus 1 encoded). >>> >>> Signed-off-by: Ariel D'Alessandro <ariel@xxxxxxxxxxxxxxxxxxxx> >>> --- >>> drivers/nvmem/Kconfig | 9 ++ >>> drivers/nvmem/Makefile | 2 + >>> drivers/nvmem/lpc18xx_eeprom.c | 266 >>> +++++++++++++++++++++++++++++++++++++++++ >>> 3 files changed, 277 insertions(+) >>> create mode 100644 drivers/nvmem/lpc18xx_eeprom.c >> >>> +static int lpc18xx_eeprom_gather_write(void *context, const void *reg, >>> + size_t reg_size, const void *val, >>> + size_t val_size) >>> +{ >>> + struct lpc18xx_eeprom_dev *eeprom = context; >>> + unsigned int offset = *(u32 *)reg; >>> + >>> + /* 3 ms of erase/program time between each writing */ >>> + while (val_size) { >>> + writel(*(u32 *)val, eeprom->mem_base + offset); >>> + usleep_range(3000, 4000); >>> + val_size -= eeprom->val_bytes; >>> + val += eeprom->val_bytes; >>> + offset += eeprom->val_bytes; >>> + } >> >> What happens here if 'val_size' is less than 4 or not dividable by 4? >> Same thing for 'offset'. >> >> I tested the driver from sysfs by writing strings into the nvmem-file >> with echo. Writing a string not dividable by 4 seems to hang the >> system. >> > > I think I know the issue here: > Could you try this patch: > > -------------------------------->cut<---------------------------------- > From 8cae10eff8ea8da9c5a8058ff75abeeddd8a8224 Mon Sep 17 00:00:00 2001 > From: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx> > Date: Mon, 26 Oct 2015 13:30:24 +0000 > Subject: [PATCH] nvmem: core: return error for non word aligned bytes > > nvmem providers have restrictions on register strides, so return error > code when users attempt to read/write buffers with sizes which are not > aligned to the word boundary. > > Without this patch the userspace would continue to try as it does not > get any error from the nvmem core, resulting in a hang. > > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx> > --- > drivers/nvmem/core.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c > index 6fd4e5a..9d11d98 100644 > --- a/drivers/nvmem/core.c > +++ b/drivers/nvmem/core.c > @@ -70,6 +70,9 @@ static ssize_t bin_attr_nvmem_read(struct file *filp, > struct kobject *kobj, > if (pos >= nvmem->size) > return 0; > > + if (count < nvmem->word_size) > + return -EINVAL; > + > if (pos + count > nvmem->size) > count = nvmem->size - pos; > > @@ -95,6 +98,9 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, > struct kobject *kobj, > if (pos >= nvmem->size) > return 0; > > + if (count < nvmem->word_size) > + return -EINVAL; > + > if (pos + count > nvmem->size) > count = nvmem->size - pos; > Patch looks good to me. I think that it solves the issue. I don't have the board here right now, so I'll check it ASAP and give some feedback. Thanks! -- Ariel D'Alessandro, VanguardiaSur www.vanguardiasur.com.ar -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html