[dpdk-dev] [PATCH v3 04/12] eal/bus: add scan, match and insert support

[Shreyansh Jain]

On Friday 16 December 2016 06:40 PM, Shreyansh Jain wrote:
> When a PMD is registred, it will associate itself with a bus.
>
> A bus is responsible for 'scan' of all the devices attached to it.
> All the scanned devices are attached to bus specific device_list.
> During the probe operation, 'match' of the drivers and devices would
> be done.
>
> Also, rather than adding a device to tail, a new device might be added to
> the list (pivoted on bus) at a predefined position, for example, adding it
> in order of addressing. Support for this is added as '*bus_insert'.
>
> This patch also adds necessary test framework to test the scan and
> match callbacks.
>
> Signed-off-by: Shreyansh Jain <shreyansh.jain at nxp.com>
> ---
>  app/test/test_bus.c                     | 265 ++++++++++++++++++++++++++++++++
>  lib/librte_eal/common/eal_common_bus.c  |  15 ++
>  lib/librte_eal/common/include/rte_bus.h |  64 ++++++++
>  3 files changed, 344 insertions(+)
>
> diff --git a/app/test/test_bus.c b/app/test/test_bus.c
> index 760d40a..ed95479 100644
> --- a/app/test/test_bus.c
> +++ b/app/test/test_bus.c
> @@ -80,12 +80,32 @@ struct dummy_bus {
>  struct rte_bus_list orig_bus_list =
>  	TAILQ_HEAD_INITIALIZER(orig_bus_list);
>
> +/* Forward declarations for callbacks from bus */
> +
> +/* Bus A
> + * Scan would register devA1 and devA2 to bus
> + */
> +int scan_fn_for_busA(struct rte_bus *bus);
> +
> +/* Bus B
> + * Scan would register devB1 and devB2 to bus
> + */
> +int scan_fn_for_busB(struct rte_bus *bus);
> +
> +/* generic implementations wrapped around by above declarations */
> +static int generic_scan_fn(struct rte_bus *bus);
> +static int generic_match_fn(struct rte_driver *drv, struct rte_device *dev);
> +
>  struct rte_bus busA = {
>  	.name = "busA", /* "busA" */
> +	.scan = scan_fn_for_busA,
> +	.match = generic_match_fn,
>  };
>
>  struct rte_bus busB = {
>  	.name = "busB", /* "busB */
> +	.scan = scan_fn_for_busB,
> +	.match = generic_match_fn,
>  };
>
>  struct rte_driver driverA = {
> @@ -184,6 +204,92 @@ dump_device_tree(void)
>  	printf("------>8-------\n");
>  }
>
> +/* @internal
> + * Move over the dummy_buses and find the entry matching the bus object
> + * passed as argument.
> + * For each device in that dummy_buses list, register.
> + *
> + * @param bus
> + *	bus to scan againt test entry
> + * @return
> + *	0 for successful scan, even if no devices are found
> + *	!0 for any error in scanning (like, invalid bus)
> + */
> +static int
> +generic_scan_fn(struct rte_bus *bus)
> +{
> +	int i = 0;
> +	struct rte_device *dev = NULL;
> +	struct dummy_bus *db = NULL;
> +
> +	if (!bus)
> +		return -1;
> +
> +	/* Extract the device tree node using the bus passed */
> +	for (i = 0; dummy_buses[i].name; i++) {
> +		if (!strcmp(dummy_buses[i].name, bus->name)) {
> +			db = &dummy_buses[i];
> +			break;
> +		}
> +	}
> +
> +	if (!db)
> +		return -1;
> +
> +	/* For all the devices in the device tree (dummy_buses), add device */
> +	for (i = 0; db->devices[i]; i++) {
> +		dev = &(db->devices[i]->dev);
> +		rte_eal_bus_add_device(bus, dev);
> +	}
> +
> +	return 0;
> +}
> +
> +/* @internal
> + * Obtain bus from driver object. Match the address of rte_device object
> + * with all the devices associated with that bus.
> + *
> + * Being a test function, all this does is validate that device object
> + * provided is available on the same bus to which driver is registered.
> + *
> + * @param drv
> + *	driver to which matching is to be performed
> + * @param dev
> + *	device object to match with driver
> + * @return
> + *	0 for successful match
> + *	!0 for failed match
> + */
> +static int
> +generic_match_fn(struct rte_driver *drv, struct rte_device *dev)
> +{
> +	struct rte_bus *bus;
> +	struct rte_device *dev_p = NULL;
> +
> +	/* Match is based entirely on address of 'dev' and 'dev_p' extracted
> +	 * from bus->device_list.
> +	 */
> +
> +	/* a driver is registered with the bus *before* the scan. */
> +	bus = drv->bus;
> +	TAILQ_FOREACH(dev_p, &bus->device_list, next) {
> +		if (dev == dev_p)
> +			return 0;
> +	}
> +
> +	return 1;
> +}
> +
> +int
> +scan_fn_for_busA(struct rte_bus *bus) {
> +	return generic_scan_fn(bus);
> +}
> +
> +int
> +scan_fn_for_busB(struct rte_bus *bus) {
> +	return generic_scan_fn(bus);
> +}
> +
>  static int
>  test_bus_setup(void)
>  {
> @@ -391,6 +497,155 @@ test_driver_unregistration_on_bus(void)
>
>  }
>
> +static int
> +test_device_unregistration_on_bus(void)
> +{
> +	int i;
> +	struct rte_bus *bus = NULL;
> +	struct rte_device *dev;
> +
> +	for (i = 0; dummy_buses[i].name; i++) {
> +		bus = rte_eal_get_bus(dummy_buses[i].name);
> +		if (!bus) {
> +			printf("Unable to find bus (%s)\n",
> +			       dummy_buses[i].name);
> +			return -1;
> +		}
> +
> +		/* For bus 'bus', unregister all devices */
> +		TAILQ_FOREACH(dev, &bus->device_list, next) {
> +			rte_eal_bus_remove_device(dev);
> +		}
> +	}
> +
> +	for (i = 0; dummy_buses[i].name; i++) {
> +		bus = rte_eal_get_bus(dummy_buses[i].name);
> +
> +		if (!TAILQ_EMPTY(&bus->device_list)) {
> +			printf("Unable to remove all devices on bus (%s)\n",
> +			       bus->name);
> +			return -1;
> +		}
> +	}
> +
> +	/* All devices from all buses have been removed */
> +	printf("All devices on all buses unregistered.\n");
> +	dump_device_tree();
> +
> +	return 0;
> +}
> +
> +/* @internal
> + * For each bus registered, call the scan function to identify devices
> + * on the bus.
> + *
> + * @param void
> + * @return
> + *	0 for successful scan
> + *	!0 for unsuccessful scan
> + *
> + */
> +static int
> +test_bus_scan(void)
> +{
> +	int ret;
> +	struct rte_bus *bus;
> +
> +	TAILQ_FOREACH(bus, &rte_bus_list, next) {
> +		/* Call the scan function for each bus */
> +		ret = bus->scan(bus);
> +		if (ret) {
> +			printf("Scan of buses failed.\n");
> +			return -1;
> +		}
> +	}
> +
> +	printf("Scan of all buses completed.\n");
> +	dump_device_tree();
> +
> +	return 0;
> +}
> +
> +/* @internal
> + * Function to perform 'probe' and link devices and drivers on a bus.
> + * This would work over all the buses registered, and all devices and drivers
> + * registered with it - call match on each pair.
> + * Aim is to test the match_fn for each bus.
> + *
> + * @param void
> + * @return
> + *	0 for successful probe
> + *	!0 for failure in probe
> + *
> + */
> +static int
> +test_probe_on_bus(void)
> +{
> +	int ret = 0;
> +	int i, j;
> +	struct rte_bus *bus = NULL;
> +	struct rte_device *dev = NULL;
> +	struct rte_driver *drv = NULL;
> +
> +	/* In case of this test:
> +	* 1. for each bus in rte_bus_list
> +	* 2.  for each device in bus->device_list
> +	* 3.   for each driver in bus->driver_list
> +	* 4.    call match
> +	* 5.    link driver and device
> +	* 6. Verify the linkage.
> +	*/

This comment style is indeed in a warning from checkpatch. My bad -
somehow I missed fixing this before sending out. v4, along with any
other major comments/reviews.

<snip>

-
Shreyansh