| Message ID | 20201210094224.15794-6-nsaenzjulienne@suse.de |
|---|---|
| State | Superseded |
| Delegated to: | Matthias Brugger |
| Headers | show |
| Series | Raspberry Pi 400/Compute Module 4 support | expand |
Hi Nicolas, On Thu, 10 Dec 2020 at 04:43, Nicolas Saenz Julienne <nsaenzjulienne@suse.de> wrote: > > Calculating the DMA offset between a bus address space and CPU's every > time we call phys_to_bus() and bus_to_phys() isn't ideal performance > wise, as it implies traversing the device tree from the device's node up > to the root. Since this information is static and available before the > device's initialization, parse it before the probe call an provide the > DMA offset in 'struct udevice' for the address translation code to use > it. > > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> > > --- > Changes since v1: > - Update commit message so as to explain better the reasoning behind > this > > drivers/core/device.c | 24 ++++++++++++++++++++++++ > include/dm/device.h | 1 + > 2 files changed, 25 insertions(+) > Firstly, please add a sandbox test for this. All driver model code is tested this way. > diff --git a/drivers/core/device.c b/drivers/core/device.c > index 4b3dcb3b37..4255bea24d 100644 > --- a/drivers/core/device.c > +++ b/drivers/core/device.c > @@ -421,6 +421,28 @@ fail: > return ret; > } > > +void device_get_dma_constraints(struct udevice *dev) > +{ > + phys_addr_t cpu; > + dma_addr_t bus; > + u64 size; > + int ret; > + > + if (!dev_of_valid(dev)) > + return; > + > + ret = dev_get_dma_range(dev, &cpu, &bus, &size); > + if (ret) { > + /* Don't complain if no 'dma-ranges' were found */ > + if (ret != -ENODEV) Don't use -ENODEV, that is very confusing. Maybe -ENOENT > + dm_warn("%s: failed to get DMA range, %d\n", > + dev->name, ret); Needs to return an error > + return; > + } > + > + dev->dma_offset = cpu - bus; > +} > + > int device_probe(struct udevice *dev) > { > const struct driver *drv; > @@ -482,6 +504,8 @@ int device_probe(struct udevice *dev) > goto fail; > } > > + device_get_dma_constraints(dev); Check error and fail Also add a new CONFIG and use CONFIG_IS_ENABLED() to check whether to use this feature. Some boards won't need it. > + > ret = uclass_pre_probe_device(dev); > if (ret) > goto fail; > diff --git a/include/dm/device.h b/include/dm/device.h > index 5bef484247..59f711e3dd 100644 > --- a/include/dm/device.h > +++ b/include/dm/device.h > @@ -161,6 +161,7 @@ struct udevice { > #ifdef CONFIG_DEVRES > struct list_head devres_head; > #endif > + u64 dma_offset; ulong? Also needs a comment and needs to be conditional on CONFIG > }; > > /* Maximum sequence number supported */ > -- > 2.29.2 > Regards, Simon
diff --git a/drivers/core/device.c b/drivers/core/device.c index 4b3dcb3b37..4255bea24d 100644 --- a/drivers/core/device.c +++ b/drivers/core/device.c @@ -421,6 +421,28 @@ fail: return ret; } +void device_get_dma_constraints(struct udevice *dev) +{ + phys_addr_t cpu; + dma_addr_t bus; + u64 size; + int ret; + + if (!dev_of_valid(dev)) + return; + + ret = dev_get_dma_range(dev, &cpu, &bus, &size); + if (ret) { + /* Don't complain if no 'dma-ranges' were found */ + if (ret != -ENODEV) + dm_warn("%s: failed to get DMA range, %d\n", + dev->name, ret); + return; + } + + dev->dma_offset = cpu - bus; +} + int device_probe(struct udevice *dev) { const struct driver *drv; @@ -482,6 +504,8 @@ int device_probe(struct udevice *dev) goto fail; } + device_get_dma_constraints(dev); + ret = uclass_pre_probe_device(dev); if (ret) goto fail; diff --git a/include/dm/device.h b/include/dm/device.h index 5bef484247..59f711e3dd 100644 --- a/include/dm/device.h +++ b/include/dm/device.h @@ -161,6 +161,7 @@ struct udevice { #ifdef CONFIG_DEVRES struct list_head devres_head; #endif + u64 dma_offset; }; /* Maximum sequence number supported */
Calculating the DMA offset between a bus address space and CPU's every time we call phys_to_bus() and bus_to_phys() isn't ideal performance wise, as it implies traversing the device tree from the device's node up to the root. Since this information is static and available before the device's initialization, parse it before the probe call an provide the DMA offset in 'struct udevice' for the address translation code to use it. Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> --- Changes since v1: - Update commit message so as to explain better the reasoning behind this drivers/core/device.c | 24 ++++++++++++++++++++++++ include/dm/device.h | 1 + 2 files changed, 25 insertions(+)