Hi Moritz, Missatge de Moritz Fischer <[email protected]> del dia dj., 10 de gen. 2019 a les 5:40: > > Add cros_ec_readmem() helpers for I2C/SPI based ECs. > Unlike the LPC based ECs the I2C/SPI based ones cannot just directly > read the mapped region, but have to resort to EC_CMD_READ_MEMMAP. > > This is useful for things like accessing fan speeds or temperatures. > > Signed-off-by: Moritz Fischer <[email protected]> > --- > > Hi all, > > This can be used for a hwmon or thermal driver such as [1], but also > alone can be used with 'ectool' via the ioctl() interface. >
ooi, did you try this with a Chromebook? Or only with your device? I was a bit worried on the side effects to expose this command to userspace, so I did a quick test, and to be honest I didn't like the result. Issuing the ioctl resulted on a reboot on the Chromebook I tested, which is not good. I didn't investigate more but I can say that this change, at least, will need some rework. I'll try to investigate a bit more on what is happening. Thanks, Enric > Thanks, > Moritz > > > Changes from v2: > - Addressed KBuild complaint about max() with size_t vs unsigned int > parameters > > Changes from v1: > - Moved to drivers/platform/proto > > > [1] https://patchwork.kernel.org/patch/9670517/ (needs work) > --- > drivers/platform/chrome/cros_ec_i2c.c | 1 + > drivers/platform/chrome/cros_ec_proto.c | 39 +++++++++++++++++++++++++ > drivers/platform/chrome/cros_ec_spi.c | 1 + > include/linux/mfd/cros_ec.h | 12 ++++++++ > 4 files changed, 53 insertions(+) > > diff --git a/drivers/platform/chrome/cros_ec_i2c.c > b/drivers/platform/chrome/cros_ec_i2c.c > index ef9b4763356f..c3a9bee37b1d 100644 > --- a/drivers/platform/chrome/cros_ec_i2c.c > +++ b/drivers/platform/chrome/cros_ec_i2c.c > @@ -303,6 +303,7 @@ static int cros_ec_i2c_probe(struct i2c_client *client, > ec_dev->irq = client->irq; > ec_dev->cmd_xfer = cros_ec_cmd_xfer_i2c; > ec_dev->pkt_xfer = cros_ec_pkt_xfer_i2c; > + ec_dev->cmd_readmem = cros_ec_readmem; > ec_dev->phys_name = client->adapter->name; > ec_dev->din_size = sizeof(struct ec_host_response_i2c) + > sizeof(struct ec_response_get_protocol_info); > diff --git a/drivers/platform/chrome/cros_ec_proto.c > b/drivers/platform/chrome/cros_ec_proto.c > index cc7baf0ecb3c..d2ba662fc713 100644 > --- a/drivers/platform/chrome/cros_ec_proto.c > +++ b/drivers/platform/chrome/cros_ec_proto.c > @@ -636,3 +636,42 @@ u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev) > return host_event; > } > EXPORT_SYMBOL(cros_ec_get_host_event); > + > +int cros_ec_readmem(struct cros_ec_device *ec, unsigned int offset, > + unsigned int bytes, void *dest) > +{ > + struct ec_params_read_memmap *params; > + struct cros_ec_command *msg; > + int ret; > + > + if (offset >= EC_MEMMAP_SIZE - bytes) > + return -EINVAL; > + > + msg = kzalloc(sizeof(*msg) + max_t(size_t, sizeof(*params), bytes), > + GFP_KERNEL); > + if (!msg) > + return -ENOMEM; > + > + msg->version = 0; > + msg->command = EC_CMD_READ_MEMMAP; > + msg->insize = bytes; > + msg->outsize = sizeof(*params); > + > + params = (struct ec_params_read_memmap *)msg->data; > + params->offset = offset; > + params->size = bytes; > + > + ret = cros_ec_cmd_xfer_status(ec, msg); > + if (ret < 0) { > + dev_warn(ec->dev, "cannot read mapped reg: %d/%d\n", > + ret, msg->result); > + goto out_free; > + } > + > + memcpy(dest, msg->data, bytes); > + > +out_free: > + kfree(msg); > + return ret; > +} > +EXPORT_SYMBOL_GPL(cros_ec_readmem); > diff --git a/drivers/platform/chrome/cros_ec_spi.c > b/drivers/platform/chrome/cros_ec_spi.c > index 2060d1483043..b95c1a25adfc 100644 > --- a/drivers/platform/chrome/cros_ec_spi.c > +++ b/drivers/platform/chrome/cros_ec_spi.c > @@ -666,6 +666,7 @@ static int cros_ec_spi_probe(struct spi_device *spi) > ec_dev->irq = spi->irq; > ec_dev->cmd_xfer = cros_ec_cmd_xfer_spi; > ec_dev->pkt_xfer = cros_ec_pkt_xfer_spi; > + ec_dev->cmd_readmem = cros_ec_readmem; > ec_dev->phys_name = dev_name(&ec_spi->spi->dev); > ec_dev->din_size = EC_MSG_PREAMBLE_COUNT + > sizeof(struct ec_host_response) + > diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h > index de8b588c8776..0228fb42dcda 100644 > --- a/include/linux/mfd/cros_ec.h > +++ b/include/linux/mfd/cros_ec.h > @@ -335,6 +335,18 @@ int cros_ec_get_next_event(struct cros_ec_device > *ec_dev, bool *wake_event); > */ > u32 cros_ec_get_host_event(struct cros_ec_device *ec_dev); > > +/** > + * cros_ec_readmem - Read mapped memory in the ChromeOS EC > + * > + * @ec: Device to read from > + * @offset: Offset to read within the mapped region > + * @bytes: number of bytes to read > + * @data: Return data > + * @return: 0 if Ok, -ve on error > + */ > +int cros_ec_readmem(struct cros_ec_device *ec, unsigned int offset, > + unsigned int bytes, void *dest); > + > /* sysfs stuff */ > extern struct attribute_group cros_ec_attr_group; > extern struct attribute_group cros_ec_lightbar_attr_group; > -- > 2.20.1 >
