From 9528e0d9c10027ae80e2aab36e30a1f730b1bbf9 Mon Sep 17 00:00:00 2001 From: Saravana Kannan Date: Fri, 5 Feb 2021 14:26:37 -0800 Subject: driver core: fw_devlink: Detect supplier devices that will never be added During the initial parsing of firmware by fw_devlink, fw_devlink might infer that some supplier firmware nodes would get populated as devices. But the inference is not always correct. This patch tries to logically detect and fix such mistakes as boot progresses or more devices probe. fw_devlink makes a fundamental assumption that once a device binds to a driver, it will populate (i.e: add as struct devices) all the child firmware nodes that could be populated as devices (if they aren't populated already). So, whenever a device probes, we check all its child firmware nodes. If a child firmware node has a corresponding device populated, we don't modify the child node or its descendants. However, if a child firmware node has not been populated as a device, we delete all the fwnode links where the child node or its descendants are suppliers. This ensures that no other device is blocked on a firmware node that will never be populated as a device. We also mark such fwnodes as NOT_DEVICE, so that no new fwnode links are created with these nodes as suppliers. Fixes: e590474768f1 ("driver core: Set fw_devlink=on by default") Tested-by: Marek Szyprowski Acked-by: Rafael J. Wysocki Signed-off-by: Saravana Kannan Link: https://lore.kernel.org/r/20210205222644.2357303-2-saravanak@google.com Signed-off-by: Greg Kroah-Hartman --- include/linux/fwnode.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/fwnode.h') diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h index fde4ad97564c..21082f11473f 100644 --- a/include/linux/fwnode.h +++ b/include/linux/fwnode.h @@ -19,8 +19,10 @@ struct device; * fwnode link flags * * LINKS_ADDED: The fwnode has already be parsed to add fwnode links. + * NOT_DEVICE: The fwnode will never be populated as a struct device. */ #define FWNODE_FLAG_LINKS_ADDED BIT(0) +#define FWNODE_FLAG_NOT_DEVICE BIT(1) struct fwnode_handle { struct fwnode_handle *secondary; -- cgit v1.2.3 From 19d0f5f6bff878277783fd98fef4ae2441d6a1d8 Mon Sep 17 00:00:00 2001 From: Saravana Kannan Date: Fri, 5 Feb 2021 14:26:39 -0800 Subject: driver core: Add fw_devlink.strict kernel param This param allows forcing all dependencies to be treated as mandatory. This will be useful for boards in which all optional dependencies like IOMMUs and DMAs need to be treated as mandatory dependencies. Tested-by: Marek Szyprowski Signed-off-by: Saravana Kannan Link: https://lore.kernel.org/r/20210205222644.2357303-4-saravanak@google.com Signed-off-by: Greg Kroah-Hartman --- Documentation/admin-guide/kernel-parameters.txt | 5 +++++ drivers/base/core.c | 12 ++++++++++++ include/linux/fwnode.h | 1 + 3 files changed, 18 insertions(+) (limited to 'include/linux/fwnode.h') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index a10b545c2070..692b63644133 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1433,6 +1433,11 @@ to enforce probe and suspend/resume ordering. rpm -- Like "on", but also use to order runtime PM. + fw_devlink.strict= + [KNL] Treat all inferred dependencies as mandatory + dependencies. This only applies for fw_devlink=on|rpm. + Format: + gamecon.map[2|3]= [HW,JOY] Multisystem joystick and NES/SNES/PSX pad support via parallel port (up to 5 devices per port) diff --git a/drivers/base/core.c b/drivers/base/core.c index c95b1daabac7..f466ab4f1c35 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1521,6 +1521,13 @@ static int __init fw_devlink_setup(char *arg) } early_param("fw_devlink", fw_devlink_setup); +static bool fw_devlink_strict; +static int __init fw_devlink_strict_setup(char *arg) +{ + return strtobool(arg, &fw_devlink_strict); +} +early_param("fw_devlink.strict", fw_devlink_strict_setup); + u32 fw_devlink_get_flags(void) { return fw_devlink_flags; @@ -1531,6 +1538,11 @@ static bool fw_devlink_is_permissive(void) return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE; } +bool fw_devlink_is_strict(void) +{ + return fw_devlink_strict && !fw_devlink_is_permissive(); +} + static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode) { if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED) diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h index 21082f11473f..d5caefe39d93 100644 --- a/include/linux/fwnode.h +++ b/include/linux/fwnode.h @@ -162,6 +162,7 @@ static inline void fwnode_init(struct fwnode_handle *fwnode, } extern u32 fw_devlink_get_flags(void); +extern bool fw_devlink_is_strict(void); int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup); void fwnode_links_purge(struct fwnode_handle *fwnode); -- cgit v1.2.3 From 74c782cff77b3533290148df1fa6f8c7db5e60d5 Mon Sep 17 00:00:00 2001 From: Saravana Kannan Date: Fri, 5 Feb 2021 14:26:41 -0800 Subject: driver core: fw_devlink: Handle suppliers that don't use driver core Device links only work between devices that use the driver core to match and bind a driver to a device. So, add an API for frameworks to let the driver core know that a fwnode has been initialized by a driver without using the driver core. Then use this information to make sure that fw_devlink doesn't make the consumers wait indefinitely on suppliers that'll never bind to a driver. Tested-by: Marek Szyprowski Signed-off-by: Saravana Kannan Link: https://lore.kernel.org/r/20210205222644.2357303-6-saravanak@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 15 +++++++++++++++ include/linux/fwnode.h | 19 +++++++++++++++++-- 2 files changed, 32 insertions(+), 2 deletions(-) (limited to 'include/linux/fwnode.h') diff --git a/drivers/base/core.c b/drivers/base/core.c index f466ab4f1c35..ea710b33bda6 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1636,6 +1636,17 @@ static int fw_devlink_create_devlink(struct device *con, sup_dev = get_dev_from_fwnode(sup_handle); if (sup_dev) { + /* + * If it's one of those drivers that don't actually bind to + * their device using driver core, then don't wait on this + * supplier device indefinitely. + */ + if (sup_dev->links.status == DL_DEV_NO_DRIVER && + sup_handle->flags & FWNODE_FLAG_INITIALIZED) { + ret = -EINVAL; + goto out; + } + /* * If this fails, it is due to cycles in device links. Just * give up on this link and treat it as invalid. @@ -1655,6 +1666,10 @@ static int fw_devlink_create_devlink(struct device *con, goto out; } + /* Supplier that's already initialized without a struct device. */ + if (sup_handle->flags & FWNODE_FLAG_INITIALIZED) + return -EINVAL; + /* * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports * cycles. So cycle detection isn't necessary and shouldn't be diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h index d5caefe39d93..dfefd43a737c 100644 --- a/include/linux/fwnode.h +++ b/include/linux/fwnode.h @@ -11,6 +11,7 @@ #include #include +#include struct fwnode_operations; struct device; @@ -18,11 +19,13 @@ struct device; /* * fwnode link flags * - * LINKS_ADDED: The fwnode has already be parsed to add fwnode links. - * NOT_DEVICE: The fwnode will never be populated as a struct device. + * LINKS_ADDED: The fwnode has already be parsed to add fwnode links. + * NOT_DEVICE: The fwnode will never be populated as a struct device. + * INITIALIZED: The hardware corresponding to fwnode has been initialized. */ #define FWNODE_FLAG_LINKS_ADDED BIT(0) #define FWNODE_FLAG_NOT_DEVICE BIT(1) +#define FWNODE_FLAG_INITIALIZED BIT(2) struct fwnode_handle { struct fwnode_handle *secondary; @@ -161,6 +164,18 @@ static inline void fwnode_init(struct fwnode_handle *fwnode, INIT_LIST_HEAD(&fwnode->suppliers); } +static inline void fwnode_dev_initialized(struct fwnode_handle *fwnode, + bool initialized) +{ + if (IS_ERR_OR_NULL(fwnode)) + return; + + if (initialized) + fwnode->flags |= FWNODE_FLAG_INITIALIZED; + else + fwnode->flags &= ~FWNODE_FLAG_INITIALIZED; +} + extern u32 fw_devlink_get_flags(void); extern bool fw_devlink_is_strict(void); int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup); -- cgit v1.2.3