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Date: Thu, 1 Oct 2020 20:37:45 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Daniel Scally <djrscally@...il.com>
Cc: yong.zhi@...el.com, sakari.ailus@...ux.intel.com,
bingbu.cao@...el.com, tian.shu.qiu@...el.com, mchehab@...nel.org,
davem@...emloft.net, robh@...nel.org, gregkh@...uxfoundation.org,
linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
jorhand@...ux.microsoft.com, kitakar@...il.com,
kieran.bingham@...asonboard.com, dan.carpenter@...cle.com
Subject: Re: [RFC PATCH v2] Add functionality to ipu3-cio2 driver allowing
software_node connections to sensors on platforms designed for Windows
On Thu, Oct 01, 2020 at 10:33:26AM +0100, Daniel Scally wrote:
Awesome work!
My, almost minor, comments below.
> Currently on platforms designed for Windows, connections between CIO2 and
> sensors are not properly defined in DSDT. This patch extends the ipu3-cio2
> driver to compensate by building software_node connections, parsing the
> connection properties from the sensor's SSDB buffer.
Drop trailing space here and in other places if any.
> Suggested-by: Jordan Hand <jorhand@...ux.microsoft.com>
>
> Signed-off-by: Daniel Scally <djrscally@...il.com>
In the tag block should not be blank lines.
...
> * Built against media_tree instead of linus's tree - there's no T: entry in
> maintainers for the ipu3-cio2 driver but I see there're recent changes in
> media_tree so thought this was the better option.
Make sense to include T: entry as well (maybe as a separate patch).
...
> +config CIO2_BRIDGE
> + bool "IPU3 CIO2 Sensors Bridge"
> + depends on VIDEO_IPU3_CIO2
> + help
> + This extension provides an API for the ipu3-cio2 driver to create
> + connections to cameras that are hidden in SSDB buffer in ACPI. It
> + can be used to enable support for cameras in detachable / hybrid
> + devices that ship with Windows.
> +
> + Say y here if your device is a detachable / hybrid laptop that comes
y -> Y
> + with Windows installed by the OEM, for example the Microsoft Surface
> + line, Lenovo Miix line or Dell 7285.
Reads better in a form of an enumeration, like
- Microsoft Surface (all existing)
- Lenovo Miix (all existing)
- Dell 7285
> + If in doubt, say n here.
n -> N
...
> -obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2.o
> +obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2-driver.o
> +
> +ipu3-cio2-driver-objs += ipu3-cio2.o
> +
> +ifeq ($(CONFIG_CIO2_BRIDGE), y)
> +ipu3-cio2-driver-objs += cio2-bridge.o
> +endif
objs is for userspace tools, here use
ipu3-cio2-driver-y += ipu3-cio2.o
ipu3-cio2-driver-$(CONFIG_CIO2_BRIDGE) = cio2-bridge.o
And actually would be nice to keep the name, so means rename ipu3-cio2.c to
something like cio2-main.c. In such case you will have:
obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2.o
ipu3-cio2-y += cio2-main.o
ipu3-cio2-$(CONFIG_CIO2_BRIDGE) = cio2-bridge.o
...
> +// SPDX-License-Identifier: GPL-2.0
Author line perhaps?
...
> +/*
> + * Extend this array with ACPI Hardware ID's of devices known to be
> + * working
> + */
> +
Redundant blank like.
> +static const struct ipu3_sensor supported_devices[] = {
> + IPU3_SENSOR("INT33BE", "INT33BE:00"),
> + IPU3_SENSOR("OVTI2680", "OVTI2680:00"),
> + IPU3_SENSOR("OVTI5648", "OVTI5648:00")
In such cases please leave comma at the last item as well. Easier to extend w/o
an additional churn.
On top of that, please avoid putting *instance* names, i.e. the second
parameters in your macro call. What code should do is to take _HID (first
parameter) and call acpi_dev_match_first_dev() or so.
> +};
> +static struct software_node cio2_hid_node = { CIO2_HID, };
Here, nevertheless, comma can be removed, since update will need to change
entire line anyway.
> +static const char * const port_names[] = {
> + "port0", "port1", "port2", "port3"
> +};
+ Comma (can be prolonged in the next / previous lines).
...
> +static int read_acpi_block(struct device *dev, char *id, void *data, u32 size)
> +{
> + union acpi_object *obj;
> + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> + struct acpi_handle *handle = ACPI_HANDLE(dev);
> + acpi_status status;
> + int ret;
> +
> + status = acpi_evaluate_object(handle, id, NULL, &buffer);
> + if (ACPI_FAILURE(status))
> + return -ENODEV;
> +
> + obj = buffer.pointer;
> + if (!obj || obj->type != ACPI_TYPE_BUFFER) {
!obj case doesn't require freeing and I would say the error message can be
amended in such case.
> + dev_err(dev, "Could't read acpi buffer\n");
> + ret = -ENODEV;
> + goto err_free_buff;
> + }
> +
> + if (obj->buffer.length > size) {
> + dev_err(dev, "Given buffer is too small\n");
> + ret = -ENODEV;
> + goto err_free_buff;
> + }
> +
> + memcpy(data, obj->buffer.pointer, obj->buffer.length);
> + kfree(buffer.pointer);
> +
> + return obj->buffer.length;
> +err_free_buff:
> + kfree(buffer.pointer);
> + return ret;
This may be deduplicated by adding ret = obj->buffer.length; in the success
branch. In such case the label would be named out_free_buf.
> +}
...
> +static int create_fwnode_properties(struct sensor *sensor,
> + struct sensor_bios_data *ssdb)
> +{
> + struct property_entry *ep_props;
> + struct property_entry *cio2_props;
> + struct property_entry *dev_props;
> + u32 *data_lanes;
> + int i;
> + /* device fwnode properties */
> + dev_props = kcalloc(3, sizeof(*dev_props), GFP_KERNEL);
> + if (!dev_props)
> + return -ENOMEM;
> +
> + dev_props[0] = PROPERTY_ENTRY_U32("clock-frequency", ssdb->mclkspeed);
> + dev_props[1] = PROPERTY_ENTRY_U8("rotation", ssdb->degree);
> +
> + memcpy(sensor->dev_props, dev_props, sizeof(*dev_props) * 3);
> + kfree(dev_props);
Why you can't do it on stack?
> + /* endpoint fwnode properties */
> +
Redundant blank like
> + data_lanes = devm_kmalloc_array(sensor->dev, ssdb->lanes, sizeof(u32),
> + GFP_KERNEL);
> +
> + if (!data_lanes)
> + return -ENOMEM;
> +
> + for (i = 0; i < ssdb->lanes; i++)
> + data_lanes[i] = i + 1;
> + ep_props = kcalloc(4, sizeof(*ep_props), GFP_KERNEL);
> + if (!ep_props)
> + return -ENOMEM;
> +
> + ep_props[0] = PROPERTY_ENTRY_U32("bus-type", 5);
> + ep_props[1] = PROPERTY_ENTRY_U32_ARRAY_LEN("data-lanes",
> + data_lanes,
> + ssdb->lanes);
> + ep_props[2] = remote_endpoints[(bridge.n_sensors * 2) + ENDPOINT_SENSOR];
> +
> + memcpy(sensor->ep_props, ep_props, sizeof(*ep_props) * 4);
> + kfree(ep_props);
Why can't be done on stack?
> +
> + /* cio2 endpoint props */
> +
> + cio2_props = kcalloc(3, sizeof(*cio2_props), GFP_KERNEL);
> + if (!cio2_props)
> + return -ENOMEM;
> +
> + cio2_props[0] = PROPERTY_ENTRY_U32_ARRAY_LEN("data-lanes",
> + data_lanes,
> + ssdb->lanes);
> + cio2_props[1] = remote_endpoints[(bridge.n_sensors * 2) + ENDPOINT_CIO2];
> +
> + memcpy(sensor->cio2_props, cio2_props, sizeof(*cio2_props) * 3);
> + kfree(cio2_props);
Ditto.
Something like
union {
...
cio2_properties[3];
} properties;
memset(properties, 0, sizeof(properties));
(and please spell properties instead of props)
> + return 0;
> +}
> +
> +static int create_connection_swnodes(struct sensor *sensor,
> + struct sensor_bios_data *ssdb)
> +{
> + struct software_node *nodes;
> +
> + nodes = kcalloc(6, sizeof(*nodes), GFP_KERNEL);
> + if (!nodes)
> + return -ENOMEM;
> +
> + nodes[SWNODE_SENSOR_HID] = NODE_SENSOR(sensor->name,
> + sensor->dev_props);
> + nodes[SWNODE_SENSOR_PORT] = NODE_PORT("port0",
> + &sensor->swnodes[SWNODE_SENSOR_HID]);
> + nodes[SWNODE_SENSOR_ENDPOINT] = NODE_ENDPOINT("endpoint0",
> + &sensor->swnodes[SWNODE_SENSOR_PORT],
> + sensor->ep_props);
> + nodes[SWNODE_CIO2_PORT] = NODE_PORT(port_names[ssdb->link],
> + &cio2_hid_node);
> + nodes[SWNODE_CIO2_ENDPOINT] = NODE_ENDPOINT("endpoint0",
> + &sensor->swnodes[SWNODE_CIO2_PORT],
> + sensor->cio2_props);
> +
> + memcpy(sensor->swnodes, nodes, sizeof(*nodes) * 6);
> + kfree(nodes);
Also, why not on stack?
> + return 0;
> +}
...
> + for (j = 4; j >= 0; j--)
> + software_node_unregister(&sensor->swnodes[j]);
Seems we may need a simple helper for this (test_printf.c has similar case),
so, what about do it here for now and probably then move to somewhere like
swnode.h or whatever holds it.
static inline software_node_unregister_nodes_reverse(const struct software_node *nodes)
{
unsigned int i = 0;
while (nodes[i].name)
i++;
while (i--)
software_node_unregister(&nodes[i]);
}
...
> + client = container_of(sensor->dev, struct i2c_client, dev);
Shouldn't be rather i2c_verify_client() ?
...
> + sensor->old_drv = container_of(sensor->dev->driver, struct i2c_driver,
> + driver);
to_i2c_driver() ?
...
> + ret = 0;
> +
No need to have a blank line here (check other similar places in the code).
> + for (i = 0; i < ARRAY_SIZE(supported_devices); i++) {
> + adev = acpi_dev_get_first_match_dev(supported_devices[i].hid,
> + NULL, -1);
Keep it one line, easy to read.
> + if (!adev)
> + continue;
> +
> + dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev);
> + if (!dev) {
> + ret = -EPROBE_DEFER;
> + goto err_rollback;
> + }
> +
> + /*
> + * We need to clone the driver of any sensors that we connect,
> + * so if they're probing we need to wait until they're finished
> + */
> +
> + if (dev->links.status == DL_DEV_PROBING) {
> + ret = -EPROBE_DEFER;
> + goto err_free_dev;
> + }
> +
> + /*
> + * If a sensor has no driver, we want to continue to try and
> + * link others
> + */
> + sd = dev_get_drvdata(dev);
> + if (!sd)
> + goto cont_free_dev;
> +
> + sensor = &bridge.sensors[bridge.n_sensors];
> + sensor->dev = dev;
> +
> + snprintf(sensor->name, 20, "%s", supported_devices[i].hid);
include/linux/mod_devicetable.h:454:#define I2C_NAME_SIZE 20
> + sensor->fwnode = fwnode_handle_get(dev->fwnode);
> + if (!sensor->fwnode)
> + goto err_free_dev;
> +
> + ret = get_acpi_ssdb_sensor_data(dev, &ssdb);
> + if (ret)
> + goto err_free_fwnode;
> +
> + ret = create_fwnode_properties(sensor, &ssdb);
> + if (ret)
> + goto err_free_fwnode;
> +
> + ret = create_connection_swnodes(sensor, &ssdb);
> + if (ret)
> + goto err_free_fwnode;
> +
> + ret = software_node_register_nodes(sensor->swnodes);
> + if (ret)
> + goto err_free_fwnode;
> +
> + fwnode = software_node_fwnode(&sensor->swnodes[SWNODE_SENSOR_HID]);
> + if (!fwnode) {
> + ret = -ENODEV;
> + goto err_free_swnodes;
> + }
> +
> + fwnode->secondary = ERR_PTR(-ENODEV);
> + dev->fwnode = fwnode;
> +
> + ret = cio2_bridge_reprobe_sensor(sensor, i);
> + if (ret)
> + goto err_free_swnodes;
> + pr_info("cio2-bridge: Found supported device %s\n",
> + supported_devices[i].hid);
Use dev_*() [dev_info()] instead of pr_*() ones.
> + bridge.n_sensors++;
> + continue;
> +cont_free_dev:
> + put_device(dev);
> + continue;
> +err_free_swnodes:
> + for (j = 4; j >= 0; j--)
> + software_node_unregister(&sensor->swnodes[j]);
See above.
> +err_free_fwnode:
> + fwnode_handle_put(sensor->fwnode);
> +err_free_dev:
> + put_device(dev);
> +err_rollback:
> + /*
> + * If an iteration of this loop results in -EPROBE_DEFER then
> + * we need to roll back any sensors that were successfully
> + * registered. Any other error and we'll skip that step, as
> + * it seems better to have one successfully connected sensor.
> + */
> +
> + if (ret == -EPROBE_DEFER)
> + cio2_bridge_unregister_sensors();
> +
> + break;
This is (all err_* labels) invariant to the loop (you break it), so, move out
of the loop...
> + }
> +
> + return ret;
...somewhere here.
...
> + ret = software_node_register(&cio2_hid_node);
> + if (ret < 0) {
> + pr_err("cio2-bridge: Failed to register the CIO2 HID node\n");
dev_err() and so on.
> + goto err_put_cio2;
> + }
...
> +#define __NO_VERSION__
What is this for?
...
> +#define NODE_SENSOR(_HID, _PROPS) \
> + ((const struct software_node) { \
> + .name = _HID, \
> + .properties = _PROPS \
Leave comma.
> + })
...
> +#define IPU3_SENSOR(_HID, _CLIENT) \
> + { \
> + .hid = _HID, \
> + .i2c_id = { \
> + {_CLIENT, 0}, \
> + { }, \
No comma for terminator type of entries.
> + } \
Leave comma.
> + }
...
> +struct ipu3_sensor {
> + const char hid[20];
Shouldn't be rather 9?
#define ACPI_ID_LEN 9
> + const struct i2c_device_id i2c_id[2];
> +};
...
> +struct sensor {
> + char name[20];
I guess it's predefined by I²C ID.
> + struct device *dev;
> + struct software_node swnodes[6];
> + struct property_entry dev_props[3];
> + struct property_entry ep_props[4];
> + struct property_entry cio2_props[3];
I'm now wondering why you can't simply put properties directly to here and do
that kcalloc / memcpy() in few functions? I mean to drop those calls and assign
properties directly. You even won't need to memset() and stack for them!
> + struct fwnode_handle *fwnode;
> + struct i2c_driver *old_drv;
> + struct i2c_driver new_drv;
> +};
...
> +} __attribute__((__packed__));
__packed is enough (it's in compiler.h IIRC).
...
> struct cio2_device *cio2;
> + struct fwnode_handle *endpoint;
> int r;
Reverse xmas tree order.
...
> + endpoint = fwnode_graph_get_next_endpoint(pci_dev->dev.fwnode, NULL);
dev_fwnode()
> + if (!endpoint) {
> + r = cio2_bridge_build(pci_dev);
> + if (r)
> + return r;
> + }
...
> +#ifdef CONFIG_CIO2_BRIDGE
IS_ENABLED()
> +
> +int cio2_bridge_build(struct pci_dev *cio2);
> +void cio2_bridge_burn(struct pci_dev *cio2);
> +
> +#else
> +
> +int cio2_bridge_build(struct pci_dev *cio2)
> +{
> + return 0;
> +}
One line.
> +void cio2_bridge_burn(struct pci_dev *cio2)
> +{
> +}
One line.
> +#endif
--
With Best Regards,
Andy Shevchenko
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