kernel/linux.git/drivers/amba/bus.c, branch v4.17.1

ARM: amba: Fix race condition with driver_override

2018-04-26T08:35:04+00:00

The driver_override implementation is susceptible to a race condition when different threads are reading vs storing a different driver override. Add locking to avoid this race condition. Cfr. commits 6265539776a0810b ("driver core: platform: fix race condition with driver_override") and 9561475db680f714 ("PCI: Fix race condition with driver_override"). Fixes: 3cf385713460eb2b ("ARM: 8256/1: driver coamba: add device binding path 'driver_override'") Signed-off-by: Geert Uytterhoeven Reviewed-by: Todd Kjos Cc: stable Signed-off-by: Greg Kroah-Hartman

ARM: amba: Make driver_override output consistent with other buses

2018-04-26T08:32:51+00:00

For AMBA devices with unconfigured driver override, the "driver_override" sysfs virtual file is empty, while it contains "(null)" for platform and PCI devices. Make AMBA consistent with other buses by dropping the test for a NULL pointer. Note that contrary to popular belief, sprintf() handles NULL pointers fine; they are printed as "(null)". Signed-off-by: Geert Uytterhoeven Cc: stable Reviewed-by: Todd Kjos Signed-off-by: Greg Kroah-Hartman

Revert "ARM: amba: Fix race condition with driver_override"

2018-04-26T08:29:57+00:00

This reverts commit 6b614a87f3f477571e319281e84dba11e0ea0a76. My backport was incorrect, as Geert pointed out :( Reported-by: Geert Uytterhoeven Cc: Todd Kjos Cc: stable Signed-off-by: Greg Kroah-Hartman

ARM: amba: Don't read past the end of sysfs "driver_override" buffer

2018-04-25T16:07:17+00:00

When printing the driver_override parameter when it is 4095 and 4094 bytes long, the printing code would access invalid memory because we need count + 1 bytes for printing. Cfr. commits 4efe874aace57dba ("PCI: Don't read past the end of sysfs "driver_override" buffer") and bf563b01c2895a4b ("driver core: platform: Don't read past the end of "driver_override" buffer"). Fixes: 3cf385713460eb2b ("ARM: 8256/1: driver coamba: add device binding path 'driver_override'") Signed-off-by: Geert Uytterhoeven Reviewed-by: Todd Kjos Cc: stable Signed-off-by: Greg Kroah-Hartman

ARM: amba: Fix race condition with driver_override

2018-04-25T16:07:10+00:00

drivers: flag buses which demand DMA configuration

2017-10-19T14:34:52+00:00

We do not want the common dma_configure() pathway to apply indiscriminately to all devices, since there are plenty of buses which do not have DMA capability, and if their child devices were used for DMA API calls it would only be indicative of a driver bug. However, there are a number of buses for which DMA is implicitly expected even when not described by firmware - those we whitelist with an automatic opt-in to dma_configure(), assuming that the DMA address space and the physical address space are equivalent if not otherwise specified. Commit 723288836628 ("of: restrict DMA configuration") introduced a short-term fix by comparing explicit bus types, but this approach is far from pretty, doesn't scale well, and fails to cope at all with bus drivers which may be built as modules, like host1x. Let's refine things by making that opt-in a property of the bus type, which neatly addresses those problems and lets the decision of whether firmware description of DMA capability should be optional or mandatory stay internal to the bus drivers themselves. Signed-off-by: Robin Murphy Acked-by: Rob Herring Acked-by: Greg Kroah-Hartman Acked-by: Thierry Reding Signed-off-by: Christoph Hellwig

amba: use dev_groups and not dev_attrs for bus_type

2017-06-09T09:00:45+00:00

The dev_attrs field has long been "depreciated" and is finally being removed, so move the driver to use the "correct" dev_groups field instead for struct bus_type. Cc: Russell King Signed-off-by: Greg Kroah-Hartman

ARM: 8596/1: amba: Support clk parents and rates assigned in DT

2016-08-12T15:47:07+00:00

Add the call to of_clk_set_defaults() into the amba probe path so that devices on the amba bus can use the assigned rates and parents feature of the common clock framework. Cc: Michael Turquette Tested-by: Jorge Ramirez Ortiz Signed-off-by: Stephen Boyd Signed-off-by: Russell King

ARM: 8566/1: drivers: amba: properly handle devices with power domains

2016-05-05T18:00:40+00:00

To read pid/cid registers, the probed device need to be properly turned on. When it is inside a power domain, the bus code should ensure that the given power domain is enabled before trying to access device's registers. However in some cases power domain (or clocks) might not be yet available. Returning -EPROBE_DEFER is not a solution in such case, because callers don't handle this special error code. Instead such devices are added to the special list and their registration is retried from periodic worker until all resources are available. Signed-off-by: Marek Szyprowski Signed-off-by: Russell King

ARM: 8256/1: driver coamba: add device binding path 'driver_override'

2015-02-10T10:23:15+00:00

As already demonstrated with PCI [1] and the platform bus [2], a driver_override property in sysfs can be used to bypass the id matching of a device to a AMBA driver. This can be used by VFIO to bind to any AMBA device requested by the user. [1] http://lists-archives.com/linux-kernel/28030441-pci-introduce-new-device-binding-path-using-pci_dev-driver_override.html [2] https://www.redhat.com/archives/libvir-list/2014-April/msg00382.html Signed-off-by: Antonios Motakis Reviewed-by: Kim Phillips Signed-off-by: Russell King