diff options
| -rw-r--r-- | doc/driver-model/README.txt | 68 | ||||
| -rw-r--r-- | drivers/core/device.c | 16 | ||||
| -rw-r--r-- | include/dm/device.h | 6 | ||||
| -rw-r--r-- | include/dm/test.h | 4 | ||||
| -rw-r--r-- | test/dm/bus.c | 68 |
5 files changed, 160 insertions, 2 deletions
diff --git a/doc/driver-model/README.txt b/doc/driver-model/README.txt index 11af35d..f9b68be 100644 --- a/doc/driver-model/README.txt +++ b/doc/driver-model/README.txt @@ -95,7 +95,7 @@ are provided in test/dm. To run them, try: You should see something like this: <...U-Boot banner...> - Running 20 driver model tests + Running 21 driver model tests Test: dm_test_autobind Test: dm_test_autoprobe Test: dm_test_bus_children @@ -104,6 +104,7 @@ You should see something like this: Device 'c-test@1': seq 1 is in use by 'd-test' Test: dm_test_bus_children_funcs Test: dm_test_bus_parent_data + Test: dm_test_bus_parent_ops Test: dm_test_children Test: dm_test_fdt Device 'd-test': seq 3 is in use by 'b-test' @@ -425,6 +426,71 @@ entirely under the control of the board author so a conflict is generally an error. +Bus Drivers +----------- + +A common use of driver model is to implement a bus, a device which provides +access to other devices. Example of buses include SPI and I2C. Typically +the bus provides some sort of transport or translation that makes it +possible to talk to the devices on the bus. + +Driver model provides a few useful features to help with implementing +buses. Firstly, a bus can request that its children store some 'parent +data' which can be used to keep track of child state. Secondly, the bus can +define methods which are called when a child is probed or removed. This is +similar to the methods the uclass driver provides. + +Here an explanation of how a bus fits with a uclass may be useful. Consider +a USB bus with several devices attached to it, each from a different (made +up) uclass: + + xhci_usb (UCLASS_USB) + eth (UCLASS_ETHERNET) + camera (UCLASS_CAMERA) + flash (UCLASS_FLASH_STORAGE) + +Each of the devices is connected to a different address on the USB bus. +The bus device wants to store this address and some other information such +as the bus speed for each device. + +To achieve this, the bus device can use dev->parent_priv in each of its +three children. This can be auto-allocated if the bus driver has a non-zero +value for per_child_auto_alloc_size. If not, then the bus device can +allocate the space itself before the child device is probed. + +Also the bus driver can define the child_pre_probe() and child_post_remove() +methods to allow it to do some processing before the child is activated or +after it is deactivated. + +Note that the information that controls this behaviour is in the bus's +driver, not the child's. In fact it is possible that child has no knowledge +that it is connected to a bus. The same child device may even be used on two +different bus types. As an example. the 'flash' device shown above may also +be connected on a SATA bus or standalone with no bus: + + xhci_usb (UCLASS_USB) + flash (UCLASS_FLASH_STORAGE) - parent data/methods defined by USB bus + + sata (UCLASS_SATA) + flash (UCLASS_FLASH_STORAGE) - parent data/methods defined by SATA bus + + flash (UCLASS_FLASH_STORAGE) - no parent data/methods (not on a bus) + +Above you can see that the driver for xhci_usb/sata controls the child's +bus methods. In the third example the device is not on a bus, and therefore +will not have these methods at all. Consider the case where the flash +device defines child methods. These would be used for *its* children, and +would be quite separate from the methods defined by the driver for the bus +that the flash device is connetced to. The act of attaching a device to a +parent device which is a bus, causes the device to start behaving like a +bus device, regardless of its own views on the matter. + +The uclass for the device can also contain data private to that uclass. +But note that each device on the bus may be a memeber of a different +uclass, and this data has nothing to do with the child data for each child +on the bus. + + Driver Lifecycle ---------------- diff --git a/drivers/core/device.c b/drivers/core/device.c index 42d250f..166b073 100644 --- a/drivers/core/device.c +++ b/drivers/core/device.c @@ -291,6 +291,12 @@ int device_probe(struct udevice *dev) } dev->seq = seq; + if (dev->parent && dev->parent->driver->child_pre_probe) { + ret = dev->parent->driver->child_pre_probe(dev); + if (ret) + goto fail; + } + if (drv->ofdata_to_platdata && dev->of_offset >= 0) { ret = drv->ofdata_to_platdata(dev); if (ret) @@ -352,12 +358,20 @@ int device_remove(struct udevice *dev) goto err_remove; } + if (dev->parent && dev->parent->driver->child_post_remove) { + ret = dev->parent->driver->child_post_remove(dev); + if (ret) { + dm_warn("%s: Device '%s' failed child_post_remove()", + __func__, dev->name); + } + } + device_free(dev); dev->seq = -1; dev->flags &= ~DM_FLAG_ACTIVATED; - return 0; + return ret; err_remove: /* We can't put the children back */ diff --git a/include/dm/device.h b/include/dm/device.h index 20207ce..c8a4072 100644 --- a/include/dm/device.h +++ b/include/dm/device.h @@ -118,6 +118,10 @@ struct udevice_id { * @remove: Called to remove a device, i.e. de-activate it * @unbind: Called to unbind a device from its driver * @ofdata_to_platdata: Called before probe to decode device tree data + * @child_pre_probe: Called before a child device is probed. The device has + * memory allocated but it has not yet been probed. + * @child_post_remove: Called after a child device is removed. The device + * has memory allocated but its device_remove() method has been called. * @priv_auto_alloc_size: If non-zero this is the size of the private data * to be allocated in the device's ->priv pointer. If zero, then the driver * is responsible for allocating any data required. @@ -143,6 +147,8 @@ struct driver { int (*remove)(struct udevice *dev); int (*unbind)(struct udevice *dev); int (*ofdata_to_platdata)(struct udevice *dev); + int (*child_pre_probe)(struct udevice *dev); + int (*child_post_remove)(struct udevice *dev); int priv_auto_alloc_size; int platdata_auto_alloc_size; int per_child_auto_alloc_size; diff --git a/include/dm/test.h b/include/dm/test.h index 7b04850..235d728 100644 --- a/include/dm/test.h +++ b/include/dm/test.h @@ -86,9 +86,11 @@ struct dm_test_uclass_priv { * struct dm_test_parent_data - parent's information on each child * * @sum: Test value used to check parent data works correctly + * @flag: Used to track calling of parent operations */ struct dm_test_parent_data { int sum; + int flag; }; /* @@ -109,6 +111,7 @@ extern struct dm_test_state global_test_state; * @fail_count: Number of tests that failed * @force_fail_alloc: Force all memory allocs to fail * @skip_post_probe: Skip uclass post-probe processing + * @removed: Used to keep track of a device that was removed */ struct dm_test_state { struct udevice *root; @@ -116,6 +119,7 @@ struct dm_test_state { int fail_count; int force_fail_alloc; int skip_post_probe; + struct udevice *removed; }; /* Test flags for each test */ diff --git a/test/dm/bus.c b/test/dm/bus.c index df8edcb..873d64e 100644 --- a/test/dm/bus.c +++ b/test/dm/bus.c @@ -14,11 +14,39 @@ DECLARE_GLOBAL_DATA_PTR; +enum { + FLAG_CHILD_PROBED = 10, + FLAG_CHILD_REMOVED = -7, +}; + +static struct dm_test_state *test_state; + static int testbus_drv_probe(struct udevice *dev) { return dm_scan_fdt_node(dev, gd->fdt_blob, dev->of_offset, false); } +static int testbus_child_pre_probe(struct udevice *dev) +{ + struct dm_test_parent_data *parent_data = dev_get_parentdata(dev); + + parent_data->flag += FLAG_CHILD_PROBED; + + return 0; +} + +static int testbus_child_post_remove(struct udevice *dev) +{ + struct dm_test_parent_data *parent_data = dev_get_parentdata(dev); + struct dm_test_state *dms = test_state; + + parent_data->flag += FLAG_CHILD_REMOVED; + if (dms) + dms->removed = dev; + + return 0; +} + static const struct udevice_id testbus_ids[] = { { .compatible = "denx,u-boot-test-bus", @@ -34,6 +62,8 @@ U_BOOT_DRIVER(testbus_drv) = { .priv_auto_alloc_size = sizeof(struct dm_test_priv), .platdata_auto_alloc_size = sizeof(struct dm_test_pdata), .per_child_auto_alloc_size = sizeof(struct dm_test_parent_data), + .child_pre_probe = testbus_child_pre_probe, + .child_post_remove = testbus_child_post_remove, }; UCLASS_DRIVER(testbus) = { @@ -172,3 +202,41 @@ static int dm_test_bus_parent_data(struct dm_test_state *dms) } DM_TEST(dm_test_bus_parent_data, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT); + +/* Test that the bus ops are called when a child is probed/removed */ +static int dm_test_bus_parent_ops(struct dm_test_state *dms) +{ + struct dm_test_parent_data *parent_data; + struct udevice *bus, *dev; + struct uclass *uc; + + test_state = dms; + ut_assertok(uclass_get_device(UCLASS_TEST_BUS, 0, &bus)); + ut_assertok(uclass_get(UCLASS_TEST_FDT, &uc)); + + uclass_foreach_dev(dev, uc) { + /* Ignore these if they are not on this bus */ + if (dev->parent != bus) + continue; + ut_asserteq_ptr(NULL, dev_get_parentdata(dev)); + + ut_assertok(device_probe(dev)); + parent_data = dev_get_parentdata(dev); + ut_asserteq(FLAG_CHILD_PROBED, parent_data->flag); + } + + uclass_foreach_dev(dev, uc) { + /* Ignore these if they are not on this bus */ + if (dev->parent != bus) + continue; + parent_data = dev_get_parentdata(dev); + ut_asserteq(FLAG_CHILD_PROBED, parent_data->flag); + ut_assertok(device_remove(dev)); + ut_asserteq_ptr(NULL, dev_get_parentdata(dev)); + ut_asserteq_ptr(dms->removed, dev); + } + test_state = NULL; + + return 0; +} +DM_TEST(dm_test_bus_parent_ops, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT); |