[4/4] platform/chrome: i2c: i2c-cros-ec-tunnel: Convert i2c tunnel to MFD Cell
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Message ID 20191121140830.4.Iddc7dd74f893297cb932e9825d413e7890633b3d@changeid
State New
Headers show
Series
  • Convert cros-ec-i2c-tunnel to MFD Cell
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Commit Message

Raul E Rangel Nov. 21, 2019, 9:10 p.m. UTC
If the i2c-cros-ec-tunnel driver is compiled into the kernel, it is
possible that i2c-cros-ec-tunnel could be probed before cros_ec_XXX
has finished initializing and setting the drvdata. This would cause a
NULL pointer panic.

Converting this driver over to an MFD solves the problem and aligns with
where the cros_ec is going.

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
---
You can now see the device node lives under the mfd device.

$ find /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/ -iname firmware_node -exec ls -l '{}' \;
/sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/firmware_node -> ../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
/sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/firmware_node -> ../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
/sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/i2c-10EC5682:00/firmware_node -> ../../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00/10EC5682:00

 drivers/i2c/busses/i2c-cros-ec-tunnel.c | 36 +++++++++----------------
 drivers/mfd/cros_ec_dev.c               | 19 +++++++++++++
 2 files changed, 32 insertions(+), 23 deletions(-)

Comments

Guenter Roeck Nov. 21, 2019, 9:40 p.m. UTC | #1
On Thu, Nov 21, 2019 at 1:11 PM Raul E Rangel <rrangel@chromium.org> wrote:
>
> If the i2c-cros-ec-tunnel driver is compiled into the kernel, it is
> possible that i2c-cros-ec-tunnel could be probed before cros_ec_XXX
> has finished initializing and setting the drvdata. This would cause a
> NULL pointer panic.
>
> Converting this driver over to an MFD solves the problem and aligns with
> where the cros_ec is going.
>

I thought the mfd maintainer objects to the use of the mfd API outside
drivers/mfd. Did that change recently ?

Guenter

> Signed-off-by: Raul E Rangel <rrangel@chromium.org>
> ---
> You can now see the device node lives under the mfd device.
>
> $ find /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/ -iname firmware_node -exec ls -l '{}' \;
> /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/firmware_node -> ../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
> /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/firmware_node -> ../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
> /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/i2c-10EC5682:00/firmware_node -> ../../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00/10EC5682:00
>
>  drivers/i2c/busses/i2c-cros-ec-tunnel.c | 36 +++++++++----------------
>  drivers/mfd/cros_ec_dev.c               | 19 +++++++++++++
>  2 files changed, 32 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-cros-ec-tunnel.c b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> index 5d91e33eb600..2e3217678fa3 100644
> --- a/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> +++ b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> @@ -6,6 +6,7 @@
>  #include <linux/acpi.h>
>  #include <linux/module.h>
>  #include <linux/i2c.h>
> +#include <linux/mfd/cros_ec.h>
>  #include <linux/platform_data/cros_ec_commands.h>
>  #include <linux/platform_data/cros_ec_proto.h>
>  #include <linux/platform_device.h>
> @@ -27,7 +28,6 @@
>  struct ec_i2c_device {
>         struct device *dev;
>         struct i2c_adapter adap;
> -       struct cros_ec_device *ec;
>
>         u16 remote_bus;
>
> @@ -176,6 +176,7 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
>  {
>         struct ec_i2c_device *bus = adap->algo_data;
>         struct device *dev = bus->dev;
> +       struct cros_ec_dev *ec = dev_get_drvdata(dev->parent);
>         const u16 bus_num = bus->remote_bus;
>         int request_len;
>         int response_len;
> @@ -183,6 +184,16 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
>         int result;
>         struct cros_ec_command *msg;
>
> +       if (!ec) {
> +               dev_err(dev, "%s: ec is missing!\n", __func__);
> +               return -EINVAL;
> +       }
> +
> +       if (!ec->ec_dev) {
> +               dev_err(dev, "%s: ec->ec_dev is missing!\n", __func__);
> +               return -EINVAL;
> +       }
> +
>         request_len = ec_i2c_count_message(i2c_msgs, num);
>         if (request_len < 0) {
>                 dev_warn(dev, "Error constructing message %d\n", request_len);
> @@ -212,7 +223,7 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
>         msg->outsize = request_len;
>         msg->insize = response_len;
>
> -       result = cros_ec_cmd_xfer_status(bus->ec, msg);
> +       result = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
>         if (result < 0) {
>                 dev_err(dev, "Error transferring EC i2c message %d\n", result);
>                 goto exit;
> @@ -241,17 +252,11 @@ static const struct i2c_algorithm ec_i2c_algorithm = {
>
>  static int ec_i2c_probe(struct platform_device *pdev)
>  {
> -       struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
>         struct device *dev = &pdev->dev;
>         struct ec_i2c_device *bus = NULL;
>         u32 remote_bus;
>         int err;
>
> -       if (!ec->cmd_xfer) {
> -               dev_err(dev, "Missing sendrecv\n");
> -               return -EINVAL;
> -       }
> -
>         bus = devm_kzalloc(dev, sizeof(*bus), GFP_KERNEL);
>         if (bus == NULL)
>                 return -ENOMEM;
> @@ -263,7 +268,6 @@ static int ec_i2c_probe(struct platform_device *pdev)
>         }
>         bus->remote_bus = remote_bus;
>
> -       bus->ec = ec;
>         bus->dev = dev;
>
>         bus->adap.owner = THIS_MODULE;
> @@ -292,25 +296,11 @@ static int ec_i2c_remove(struct platform_device *dev)
>         return 0;
>  }
>
> -static const struct of_device_id cros_ec_i2c_of_match[] = {
> -       { .compatible = "google,cros-ec-i2c-tunnel" },
> -       {},
> -};
> -MODULE_DEVICE_TABLE(of, cros_ec_i2c_of_match);
> -
> -static const struct acpi_device_id cros_ec_i2c_tunnel_acpi_id[] = {
> -       { "GOOG0012", 0 },
> -       { }
> -};
> -MODULE_DEVICE_TABLE(acpi, cros_ec_i2c_tunnel_acpi_id);
> -
>  static struct platform_driver ec_i2c_tunnel_driver = {
>         .probe = ec_i2c_probe,
>         .remove = ec_i2c_remove,
>         .driver = {
>                 .name = "cros-ec-i2c-tunnel",
> -               .acpi_match_table = ACPI_PTR(cros_ec_i2c_tunnel_acpi_id),
> -               .of_match_table = of_match_ptr(cros_ec_i2c_of_match),
>         },
>  };
>
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index 1efdba18f20b..61b20e061f75 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -113,6 +113,18 @@ static const struct mfd_cell cros_ec_vbc_cells[] = {
>         { .name = "cros-ec-vbc", }
>  };
>
> +static struct mfd_cell_acpi_match cros_ec_i2c_tunnel_acpi_match = {
> +       .pnpid = "GOOG0012"
> +};
> +
> +static struct mfd_cell cros_ec_fw_cells[] = {
> +       {
> +               .name = "cros-ec-i2c-tunnel",
> +               .acpi_match = &cros_ec_i2c_tunnel_acpi_match,
> +               .of_compatible = "google,cros-ec-i2c-tunnel"
> +       },
> +};
> +
>  int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
>  {
>         struct cros_ec_command *msg;
> @@ -485,6 +497,13 @@ static int ec_device_probe(struct platform_device *pdev)
>                          "failed to add cros-ec platform devices: %d\n",
>                          retval);
>
> +       retval = mfd_add_hotplug_devices(ec->dev, cros_ec_fw_cells,
> +                                        ARRAY_SIZE(cros_ec_fw_cells));
> +       if (retval)
> +               dev_warn(ec->dev,
> +                        "failed to add cros-ec fw platform devices: %d\n",
> +                        retval);
> +
>         /* Check whether this EC instance has a VBC NVRAM */
>         node = ec->ec_dev->dev->of_node;
>         if (of_property_read_bool(node, "google,has-vbc-nvram")) {
> --
> 2.24.0.432.g9d3f5f5b63-goog
>
Raul E Rangel Nov. 21, 2019, 9:49 p.m. UTC | #2
On Thu, Nov 21, 2019 at 2:40 PM Guenter Roeck <groeck@google.com> wrote:
>
> On Thu, Nov 21, 2019 at 1:11 PM Raul E Rangel <rrangel@chromium.org> wrote:
> >
> > If the i2c-cros-ec-tunnel driver is compiled into the kernel, it is
> > possible that i2c-cros-ec-tunnel could be probed before cros_ec_XXX
> > has finished initializing and setting the drvdata. This would cause a
> > NULL pointer panic.
> >
> > Converting this driver over to an MFD solves the problem and aligns with
> > where the cros_ec is going.
> >
>
> I thought the mfd maintainer objects to the use of the mfd API outside
> drivers/mfd. Did that change recently ?

The MFD apis are only used in drivers/mfd/cros_ec_dev.c.
drivers/i2c/busses/i2c-cros-ec-tunnel.c just registers as a simple
driver.

Raul
Lee Jones Nov. 22, 2019, 8:03 a.m. UTC | #3
On Thu, 21 Nov 2019, Guenter Roeck wrote:

> On Thu, Nov 21, 2019 at 1:11 PM Raul E Rangel <rrangel@chromium.org> wrote:
> >
> > If the i2c-cros-ec-tunnel driver is compiled into the kernel, it is
> > possible that i2c-cros-ec-tunnel could be probed before cros_ec_XXX
> > has finished initializing and setting the drvdata. This would cause a
> > NULL pointer panic.
> >
> > Converting this driver over to an MFD solves the problem and aligns with
> > where the cros_ec is going.
> >
> 
> I thought the mfd maintainer objects to the use of the mfd API outside
> drivers/mfd. Did that change recently ?

It hasn't changed, although I don't see that here?

> > Signed-off-by: Raul E Rangel <rrangel@chromium.org>
> > ---
> > You can now see the device node lives under the mfd device.
> >
> > $ find /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/ -iname firmware_node -exec ls -l '{}' \;
> > /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/firmware_node -> ../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
> > /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/firmware_node -> ../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
> > /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/i2c-10EC5682:00/firmware_node -> ../../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00/10EC5682:00
> >
> >  drivers/i2c/busses/i2c-cros-ec-tunnel.c | 36 +++++++++----------------
> >  drivers/mfd/cros_ec_dev.c               | 19 +++++++++++++
> >  2 files changed, 32 insertions(+), 23 deletions(-)
Guenter Roeck Nov. 22, 2019, 10:42 a.m. UTC | #4
On Fri, Nov 22, 2019 at 12:03 AM Lee Jones <lee.jones@linaro.org> wrote:
>
> On Thu, 21 Nov 2019, Guenter Roeck wrote:
>
> > On Thu, Nov 21, 2019 at 1:11 PM Raul E Rangel <rrangel@chromium.org> wrote:
> > >
> > > If the i2c-cros-ec-tunnel driver is compiled into the kernel, it is
> > > possible that i2c-cros-ec-tunnel could be probed before cros_ec_XXX
> > > has finished initializing and setting the drvdata. This would cause a
> > > NULL pointer panic.
> > >
> > > Converting this driver over to an MFD solves the problem and aligns with
> > > where the cros_ec is going.
> > >
> >
> > I thought the mfd maintainer objects to the use of the mfd API outside
> > drivers/mfd. Did that change recently ?
>
> It hasn't changed, although I don't see that here?
>
Sorry, I was confused.

Guenter

> > > Signed-off-by: Raul E Rangel <rrangel@chromium.org>
> > > ---
> > > You can now see the device node lives under the mfd device.
> > >
> > > $ find /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/ -iname firmware_node -exec ls -l '{}' \;
> > > /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/firmware_node -> ../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
> > > /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/firmware_node -> ../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
> > > /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/i2c-10EC5682:00/firmware_node -> ../../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00/10EC5682:00
> > >
> > >  drivers/i2c/busses/i2c-cros-ec-tunnel.c | 36 +++++++++----------------
> > >  drivers/mfd/cros_ec_dev.c               | 19 +++++++++++++
> > >  2 files changed, 32 insertions(+), 23 deletions(-)
>
> --
> Lee Jones [李琼斯]
> Linaro Services Technical Lead
> Linaro.org │ Open source software for ARM SoCs
> Follow Linaro: Facebook | Twitter | Blog
Enric Balletbo i Serra Nov. 25, 2019, 4:51 p.m. UTC | #5
Hi Raul,

On 21/11/19 22:10, Raul E Rangel wrote:
> If the i2c-cros-ec-tunnel driver is compiled into the kernel, it is
> possible that i2c-cros-ec-tunnel could be probed before cros_ec_XXX
> has finished initializing and setting the drvdata. This would cause a
> NULL pointer panic.
> 
> Converting this driver over to an MFD solves the problem and aligns with
> where the cros_ec is going.
> 
> Signed-off-by: Raul E Rangel <rrangel@chromium.org>
> ---
> You can now see the device node lives under the mfd device.
> 
> $ find /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/ -iname firmware_node -exec ls -l '{}' \;
> /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/firmware_node -> ../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
> /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/firmware_node -> ../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
> /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/i2c-10EC5682:00/firmware_node -> ../../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00/10EC5682:00
> 
>  drivers/i2c/busses/i2c-cros-ec-tunnel.c | 36 +++++++++----------------
>  drivers/mfd/cros_ec_dev.c               | 19 +++++++++++++
>  2 files changed, 32 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-cros-ec-tunnel.c b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> index 5d91e33eb600..2e3217678fa3 100644
> --- a/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> +++ b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> @@ -6,6 +6,7 @@
>  #include <linux/acpi.h>
>  #include <linux/module.h>
>  #include <linux/i2c.h>
> +#include <linux/mfd/cros_ec.h>
>  #include <linux/platform_data/cros_ec_commands.h>
>  #include <linux/platform_data/cros_ec_proto.h>
>  #include <linux/platform_device.h>
> @@ -27,7 +28,6 @@
>  struct ec_i2c_device {
>  	struct device *dev;
>  	struct i2c_adapter adap;
> -	struct cros_ec_device *ec;
>  
>  	u16 remote_bus;
>  
> @@ -176,6 +176,7 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
>  {
>  	struct ec_i2c_device *bus = adap->algo_data;
>  	struct device *dev = bus->dev;
> +	struct cros_ec_dev *ec = dev_get_drvdata(dev->parent);
>  	const u16 bus_num = bus->remote_bus;
>  	int request_len;
>  	int response_len;
> @@ -183,6 +184,16 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
>  	int result;
>  	struct cros_ec_command *msg;
>  
> +	if (!ec) {
> +		dev_err(dev, "%s: ec is missing!\n", __func__);
> +		return -EINVAL;
> +	}
> +
> +	if (!ec->ec_dev) {
> +		dev_err(dev, "%s: ec->ec_dev is missing!\n", __func__);
> +		return -EINVAL;
> +	}
> +

Are those checks needed? Is that possible?

>  	request_len = ec_i2c_count_message(i2c_msgs, num);
>  	if (request_len < 0) {
>  		dev_warn(dev, "Error constructing message %d\n", request_len);
> @@ -212,7 +223,7 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
>  	msg->outsize = request_len;
>  	msg->insize = response_len;
>  
> -	result = cros_ec_cmd_xfer_status(bus->ec, msg);
> +	result = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
>  	if (result < 0) {
>  		dev_err(dev, "Error transferring EC i2c message %d\n", result);
>  		goto exit;
> @@ -241,17 +252,11 @@ static const struct i2c_algorithm ec_i2c_algorithm = {
>  
>  static int ec_i2c_probe(struct platform_device *pdev)
>  {
> -	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
>  	struct device *dev = &pdev->dev;
>  	struct ec_i2c_device *bus = NULL;
>  	u32 remote_bus;
>  	int err;
>  
> -	if (!ec->cmd_xfer) {
> -		dev_err(dev, "Missing sendrecv\n");
> -		return -EINVAL;
> -	}
> -
>  	bus = devm_kzalloc(dev, sizeof(*bus), GFP_KERNEL);
>  	if (bus == NULL)
>  		return -ENOMEM;
> @@ -263,7 +268,6 @@ static int ec_i2c_probe(struct platform_device *pdev)
>  	}
>  	bus->remote_bus = remote_bus;
>  
> -	bus->ec = ec;
>  	bus->dev = dev;
>  
>  	bus->adap.owner = THIS_MODULE;
> @@ -292,25 +296,11 @@ static int ec_i2c_remove(struct platform_device *dev)
>  	return 0;
>  }
>  
> -static const struct of_device_id cros_ec_i2c_of_match[] = {
> -	{ .compatible = "google,cros-ec-i2c-tunnel" },
> -	{},
> -};
> -MODULE_DEVICE_TABLE(of, cros_ec_i2c_of_match);
> -
> -static const struct acpi_device_id cros_ec_i2c_tunnel_acpi_id[] = {
> -	{ "GOOG0012", 0 },

So, you're removing something that you just added in a previous patch. So is
really the change in the previous patch needed?


> -	{ }
> -};
> -MODULE_DEVICE_TABLE(acpi, cros_ec_i2c_tunnel_acpi_id);
> -
>  static struct platform_driver ec_i2c_tunnel_driver = {
>  	.probe = ec_i2c_probe,
>  	.remove = ec_i2c_remove,
>  	.driver = {
>  		.name = "cros-ec-i2c-tunnel",
> -		.acpi_match_table = ACPI_PTR(cros_ec_i2c_tunnel_acpi_id),
> -		.of_match_table = of_match_ptr(cros_ec_i2c_of_match),

I don't understand this change, why? The id should be in the driver to match.

>  	},
>  };
>  
> diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> index 1efdba18f20b..61b20e061f75 100644
> --- a/drivers/mfd/cros_ec_dev.c
> +++ b/drivers/mfd/cros_ec_dev.c
> @@ -113,6 +113,18 @@ static const struct mfd_cell cros_ec_vbc_cells[] = {
>  	{ .name = "cros-ec-vbc", }
>  };
>  
> +static struct mfd_cell_acpi_match cros_ec_i2c_tunnel_acpi_match = {
> +	.pnpid = "GOOG0012"
> +};
> +
> +static struct mfd_cell cros_ec_fw_cells[] = {
> +	{
> +		.name = "cros-ec-i2c-tunnel",
> +		.acpi_match = &cros_ec_i2c_tunnel_acpi_match,
> +		.of_compatible = "google,cros-ec-i2c-tunnel"

Ah, I see. The acpi_match and the of_compatible should be in the
i2c-cros-ec-tunnel driver not here. Why you changed? Didn't work?

> +	},
> +};
> +
>  int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
>  {
>  	struct cros_ec_command *msg;
> @@ -485,6 +497,13 @@ static int ec_device_probe(struct platform_device *pdev)
>  			 "failed to add cros-ec platform devices: %d\n",
>  			 retval);
>  
> +	retval = mfd_add_hotplug_devices(ec->dev, cros_ec_fw_cells,
> +					 ARRAY_SIZE(cros_ec_fw_cells));
> +	if (retval)
> +		dev_warn(ec->dev,
> +			 "failed to add cros-ec fw platform devices: %d\n",
> +			 retval);
> +

I think this should go inside the cros_ec_platform_cells, so drop this and
add the "cros-ec-i2c-tunnel" in the cros_ec_platform_cells[] table is enough.

Thanks,
 Enric


>  	/* Check whether this EC instance has a VBC NVRAM */
>  	node = ec->ec_dev->dev->of_node;
>  	if (of_property_read_bool(node, "google,has-vbc-nvram")) {
>
Raul E Rangel Nov. 25, 2019, 7:38 p.m. UTC | #6
> > +     if (!ec) {
> > +             dev_err(dev, "%s: ec is missing!\n", __func__);
> > +             return -EINVAL;
> > +     }
> > +
> > +     if (!ec->ec_dev) {
> > +             dev_err(dev, "%s: ec->ec_dev is missing!\n", __func__);
> > +             return -EINVAL;
> > +     }
> > +
>
> Are those checks needed? Is that possible?
I don't think it's possible anymore now that the driver has been
converted into an MFD Cell. Previously it would panic if the
i2c-cros-ec-tunnel was compiled as a built-in because it could be
probed before the cros_ec. If the i2c-cros-ec-tunnel was compiled as a
module it worked as expected. So this patch really just fixes the race
condition on initialization.

[    3.733397] BUG: kernel NULL pointer dereference, address: 0000000000000060
...
[    3.734358] RIP: 0010:ec_i2c_probe+0x2f/0x158
0xffffffff81834990 is in ec_i2c_probe
(/mnt/host/source/src/third_party/kernel/next/drivers/i2c/busses/i2c-cros-ec-tunnel.c:250).
245             struct device *dev = &pdev->dev;
246             struct ec_i2c_device *bus = NULL;
247             u32 remote_bus;
248             int err;
249
250             if (!ec->cmd_xfer) {
251                     dev_err(dev, "Missing sendrecv\n");
252                     return -EINVAL;
253             }
254

If you want, I can remove them. But I also don't think they hurt
anything either.

> > -static const struct of_device_id cros_ec_i2c_of_match[] = {
> > -     { .compatible = "google,cros-ec-i2c-tunnel" },
> > -     {},
> > -};
> > -MODULE_DEVICE_TABLE(of, cros_ec_i2c_of_match);
> > -
> > -static const struct acpi_device_id cros_ec_i2c_tunnel_acpi_id[] = {
> > -     { "GOOG0012", 0 },
>
> So, you're removing something that you just added in a previous patch. So is
> really the change in the previous patch needed?

The previous patch also switched over to using
device_property_read_u32, so it's still needed.

> > -     { }
> > -};
> > -MODULE_DEVICE_TABLE(acpi, cros_ec_i2c_tunnel_acpi_id);
> > -
> >  static struct platform_driver ec_i2c_tunnel_driver = {
> >       .probe = ec_i2c_probe,
> >       .remove = ec_i2c_remove,
> >       .driver = {
> >               .name = "cros-ec-i2c-tunnel",
> > -             .acpi_match_table = ACPI_PTR(cros_ec_i2c_tunnel_acpi_id),
> > -             .of_match_table = of_match_ptr(cros_ec_i2c_of_match),
>
> I don't understand this change, why? The id should be in the driver to match.

I removed it here because I want the driver to enumerate as an MFD
cell instead of a stand alone driver.

> >       },
> >  };
> >
> > diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
> > index 1efdba18f20b..61b20e061f75 100644
> > --- a/drivers/mfd/cros_ec_dev.c
> > +++ b/drivers/mfd/cros_ec_dev.c
> > @@ -113,6 +113,18 @@ static const struct mfd_cell cros_ec_vbc_cells[] = {
> >       { .name = "cros-ec-vbc", }
> >  };
> >
> > +static struct mfd_cell_acpi_match cros_ec_i2c_tunnel_acpi_match = {
> > +     .pnpid = "GOOG0012"
> > +};
> > +
> > +static struct mfd_cell cros_ec_fw_cells[] = {
> > +     {
> > +             .name = "cros-ec-i2c-tunnel",
> > +             .acpi_match = &cros_ec_i2c_tunnel_acpi_match,
> > +             .of_compatible = "google,cros-ec-i2c-tunnel"
>
> Ah, I see. The acpi_match and the of_compatible should be in the
> i2c-cros-ec-tunnel driver not here. Why you changed? Didn't work?

The cell needs to be the one that defines the ACPI match so the MFD
can find the node and set the parent correctly.

>
> > +     },
> > +};
> > +
> >  int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
> >  {
> >       struct cros_ec_command *msg;
> > @@ -485,6 +497,13 @@ static int ec_device_probe(struct platform_device *pdev)
> >                        "failed to add cros-ec platform devices: %d\n",
> >                        retval);
> >
> > +     retval = mfd_add_hotplug_devices(ec->dev, cros_ec_fw_cells,
> > +                                      ARRAY_SIZE(cros_ec_fw_cells));
> > +     if (retval)
> > +             dev_warn(ec->dev,
> > +                      "failed to add cros-ec fw platform devices: %d\n",
> > +                      retval);
> > +
>
> I think this should go inside the cros_ec_platform_cells, so drop this and
> add the "cros-ec-i2c-tunnel" in the cros_ec_platform_cells[] table is enough.

Good idea. I'll do that.

Thanks
Lee Jones Dec. 9, 2019, 1:17 p.m. UTC | #7
On Thu, 21 Nov 2019, Raul E Rangel wrote:

> If the i2c-cros-ec-tunnel driver is compiled into the kernel, it is
> possible that i2c-cros-ec-tunnel could be probed before cros_ec_XXX
> has finished initializing and setting the drvdata. This would cause a
> NULL pointer panic.
> 
> Converting this driver over to an MFD solves the problem and aligns with
> where the cros_ec is going.
> 
> Signed-off-by: Raul E Rangel <rrangel@chromium.org>
> ---
> You can now see the device node lives under the mfd device.
> 
> $ find /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/ -iname firmware_node -exec ls -l '{}' \;
> /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/firmware_node -> ../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
> /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/firmware_node -> ../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
> /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/i2c-10EC5682:00/firmware_node -> ../../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00/10EC5682:00
> 
>  drivers/i2c/busses/i2c-cros-ec-tunnel.c | 36 +++++++++----------------
>  drivers/mfd/cros_ec_dev.c               | 19 +++++++++++++

For my own reference:
  Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>
Enric Balletbo i Serra Dec. 9, 2019, 2:41 p.m. UTC | #8
Hi Lee,

On 9/12/19 14:17, Lee Jones wrote:
> On Thu, 21 Nov 2019, Raul E Rangel wrote:
> 
>> If the i2c-cros-ec-tunnel driver is compiled into the kernel, it is
>> possible that i2c-cros-ec-tunnel could be probed before cros_ec_XXX
>> has finished initializing and setting the drvdata. This would cause a
>> NULL pointer panic.
>>
>> Converting this driver over to an MFD solves the problem and aligns with
>> where the cros_ec is going.
>>
>> Signed-off-by: Raul E Rangel <rrangel@chromium.org>
>> ---
>> You can now see the device node lives under the mfd device.
>>
>> $ find /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/ -iname firmware_node -exec ls -l '{}' \;
>> /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/firmware_node -> ../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
>> /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/firmware_node -> ../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00
>> /sys/bus/platform/devices/cros-ec-dev.0.auto/cros-ec-i2c-tunnel.12.auto/i2c-9/i2c-10EC5682:00/firmware_node -> ../../../../../../../../LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:1c/PNP0C09:00/GOOG0004:00/GOOG0012:00/10EC5682:00
>>
>>  drivers/i2c/busses/i2c-cros-ec-tunnel.c | 36 +++++++++----------------
>>  drivers/mfd/cros_ec_dev.c               | 19 +++++++++++++
> 
> For my own reference:
>   Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>
> 

Note that there is a v2 for this patch and I did some comments [1]

Thanks,
 Enric

[1] https://patchwork.ozlabs.org/patch/1200560/

Patch
diff mbox series

diff --git a/drivers/i2c/busses/i2c-cros-ec-tunnel.c b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
index 5d91e33eb600..2e3217678fa3 100644
--- a/drivers/i2c/busses/i2c-cros-ec-tunnel.c
+++ b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
@@ -6,6 +6,7 @@ 
 #include <linux/acpi.h>
 #include <linux/module.h>
 #include <linux/i2c.h>
+#include <linux/mfd/cros_ec.h>
 #include <linux/platform_data/cros_ec_commands.h>
 #include <linux/platform_data/cros_ec_proto.h>
 #include <linux/platform_device.h>
@@ -27,7 +28,6 @@ 
 struct ec_i2c_device {
 	struct device *dev;
 	struct i2c_adapter adap;
-	struct cros_ec_device *ec;
 
 	u16 remote_bus;
 
@@ -176,6 +176,7 @@  static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
 {
 	struct ec_i2c_device *bus = adap->algo_data;
 	struct device *dev = bus->dev;
+	struct cros_ec_dev *ec = dev_get_drvdata(dev->parent);
 	const u16 bus_num = bus->remote_bus;
 	int request_len;
 	int response_len;
@@ -183,6 +184,16 @@  static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
 	int result;
 	struct cros_ec_command *msg;
 
+	if (!ec) {
+		dev_err(dev, "%s: ec is missing!\n", __func__);
+		return -EINVAL;
+	}
+
+	if (!ec->ec_dev) {
+		dev_err(dev, "%s: ec->ec_dev is missing!\n", __func__);
+		return -EINVAL;
+	}
+
 	request_len = ec_i2c_count_message(i2c_msgs, num);
 	if (request_len < 0) {
 		dev_warn(dev, "Error constructing message %d\n", request_len);
@@ -212,7 +223,7 @@  static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
 	msg->outsize = request_len;
 	msg->insize = response_len;
 
-	result = cros_ec_cmd_xfer_status(bus->ec, msg);
+	result = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 	if (result < 0) {
 		dev_err(dev, "Error transferring EC i2c message %d\n", result);
 		goto exit;
@@ -241,17 +252,11 @@  static const struct i2c_algorithm ec_i2c_algorithm = {
 
 static int ec_i2c_probe(struct platform_device *pdev)
 {
-	struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
 	struct device *dev = &pdev->dev;
 	struct ec_i2c_device *bus = NULL;
 	u32 remote_bus;
 	int err;
 
-	if (!ec->cmd_xfer) {
-		dev_err(dev, "Missing sendrecv\n");
-		return -EINVAL;
-	}
-
 	bus = devm_kzalloc(dev, sizeof(*bus), GFP_KERNEL);
 	if (bus == NULL)
 		return -ENOMEM;
@@ -263,7 +268,6 @@  static int ec_i2c_probe(struct platform_device *pdev)
 	}
 	bus->remote_bus = remote_bus;
 
-	bus->ec = ec;
 	bus->dev = dev;
 
 	bus->adap.owner = THIS_MODULE;
@@ -292,25 +296,11 @@  static int ec_i2c_remove(struct platform_device *dev)
 	return 0;
 }
 
-static const struct of_device_id cros_ec_i2c_of_match[] = {
-	{ .compatible = "google,cros-ec-i2c-tunnel" },
-	{},
-};
-MODULE_DEVICE_TABLE(of, cros_ec_i2c_of_match);
-
-static const struct acpi_device_id cros_ec_i2c_tunnel_acpi_id[] = {
-	{ "GOOG0012", 0 },
-	{ }
-};
-MODULE_DEVICE_TABLE(acpi, cros_ec_i2c_tunnel_acpi_id);
-
 static struct platform_driver ec_i2c_tunnel_driver = {
 	.probe = ec_i2c_probe,
 	.remove = ec_i2c_remove,
 	.driver = {
 		.name = "cros-ec-i2c-tunnel",
-		.acpi_match_table = ACPI_PTR(cros_ec_i2c_tunnel_acpi_id),
-		.of_match_table = of_match_ptr(cros_ec_i2c_of_match),
 	},
 };
 
diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index 1efdba18f20b..61b20e061f75 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -113,6 +113,18 @@  static const struct mfd_cell cros_ec_vbc_cells[] = {
 	{ .name = "cros-ec-vbc", }
 };
 
+static struct mfd_cell_acpi_match cros_ec_i2c_tunnel_acpi_match = {
+	.pnpid = "GOOG0012"
+};
+
+static struct mfd_cell cros_ec_fw_cells[] = {
+	{
+		.name = "cros-ec-i2c-tunnel",
+		.acpi_match = &cros_ec_i2c_tunnel_acpi_match,
+		.of_compatible = "google,cros-ec-i2c-tunnel"
+	},
+};
+
 int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
 {
 	struct cros_ec_command *msg;
@@ -485,6 +497,13 @@  static int ec_device_probe(struct platform_device *pdev)
 			 "failed to add cros-ec platform devices: %d\n",
 			 retval);
 
+	retval = mfd_add_hotplug_devices(ec->dev, cros_ec_fw_cells,
+					 ARRAY_SIZE(cros_ec_fw_cells));
+	if (retval)
+		dev_warn(ec->dev,
+			 "failed to add cros-ec fw platform devices: %d\n",
+			 retval);
+
 	/* Check whether this EC instance has a VBC NVRAM */
 	node = ec->ec_dev->dev->of_node;
 	if (of_property_read_bool(node, "google,has-vbc-nvram")) {