path: root/drivers/gpu/host1x
diff options
authorRobin Murphy <>2017-10-12 16:56:14 +0100
committerChristoph Hellwig <>2017-10-19 16:34:52 +0200
commitd89e2378a97fafdc74cbf997e7c88af75b81610a (patch)
tree1291cfc9e6a129e135f99449c007a59266f3a4d2 /drivers/gpu/host1x
parent33d930e59a98fa10a0db9f56c7fa2f21a4aef9b9 (diff)
drivers: flag buses which demand DMA configuration
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 <>
Diffstat (limited to 'drivers/gpu/host1x')
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/gpu/host1x/bus.c b/drivers/gpu/host1x/bus.c
index f9cde03030fd..ed03b3243195 100644
--- a/drivers/gpu/host1x/bus.c
+++ b/drivers/gpu/host1x/bus.c
@@ -320,6 +320,7 @@ struct bus_type host1x_bus_type = {
.name = "host1x",
.match = host1x_device_match,
.pm = &host1x_device_pm_ops,
+ .force_dma = true,
static void __host1x_device_del(struct host1x_device *device)