| Message ID | 1411141886-11310-1-git-send-email-msalter@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Fri, Sep 19, 2014 at 04:51:26PM +0100, Mark Salter wrote: > The default dma_ops for devices on arm64 systems are noncoherent in > nature and rely upon special operations and bounce buffers to > perform a device DMA operation to/from memory. Some drivers rely > upon coherent operations involving suitably capable hardware. In > this case, a "dma-coherent" property will exist on the corresponding > Device Tree node for the bridge device, or one of its ancestors. > This patch adds support for applying a DMA coherent dma_ops for > PCI devices in the case of such a property. > > Signed-off-by: Jon Masters <jcm@redhat.com> > [added search for device with of_node] > Signed-off-by: Mark Salter <msalter@redhat.com> > --- > arch/arm64/mm/dma-mapping.c | 21 +++++++++++++++++++-- > 1 file changed, 19 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c > index 4164c5a..0e26bd7 100644 > --- a/arch/arm64/mm/dma-mapping.c > +++ b/arch/arm64/mm/dma-mapping.c > @@ -23,10 +23,12 @@ > #include <linux/dma-mapping.h> > #include <linux/dma-contiguous.h> > #include <linux/of.h> > +#include <linux/of_address.h> > #include <linux/platform_device.h> > #include <linux/vmalloc.h> > #include <linux/swiotlb.h> > #include <linux/amba/bus.h> > +#include <linux/pci.h> > > #include <asm/cacheflush.h> > > @@ -316,8 +318,18 @@ static int dma_bus_notifier(struct notifier_block *nb, > if (event != BUS_NOTIFY_ADD_DEVICE) > return NOTIFY_DONE; > > - if (of_property_read_bool(dev->of_node, "dma-coherent")) > - set_dma_ops(dev, &coherent_swiotlb_dma_ops); > + /* > + * Some devices won't have an of_node but a bus controller/bridge will. > + * Search up the device chain until we find an of_node to check. > + */ > + while (dev) { > + if (dev->of_node) { > + if (of_dma_is_coherent(dev->of_node)) > + set_dma_ops(_dev, &coherent_swiotlb_dma_ops); > + break; > + } > + dev = dev->parent; > + } Hmm, how does this interact with of_dma_configure? I don't think the dma-coherent property is inherited there, so I'm uneasy about doing this for buses other than PCI (i.e. the platform bus). In other words, we should move to using of_dma_configure for the platform and amba buses, and have a separate notifier for the PCI bus. Is it likely that people will have a mixture of coherent and non-coherent devices behind the same host controller? Will > return NOTIFY_OK; > } > @@ -330,6 +342,10 @@ static struct notifier_block amba_bus_nb = { > .notifier_call = dma_bus_notifier, > }; > > +static struct notifier_block pci_bus_nb = { > + .notifier_call = dma_bus_notifier, > +}; > + > extern int swiotlb_late_init_with_default_size(size_t default_size); > > static int __init swiotlb_late_init(void) > @@ -341,6 +357,7 @@ static int __init swiotlb_late_init(void) > */ > bus_register_notifier(&platform_bus_type, &platform_bus_nb); > bus_register_notifier(&amba_bustype, &amba_bus_nb); > + bus_register_notifier(&pci_bus_type, &pci_bus_nb); > > dma_ops = &noncoherent_swiotlb_dma_ops; > > -- > 1.9.3 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On 09/19/2014 12:28 PM, Will Deacon wrote: > On Fri, Sep 19, 2014 at 04:51:26PM +0100, Mark Salter wrote: >> The default dma_ops for devices on arm64 systems are noncoherent in >> nature and rely upon special operations and bounce buffers to >> perform a device DMA operation to/from memory. Some drivers rely >> upon coherent operations involving suitably capable hardware. In >> this case, a "dma-coherent" property will exist on the corresponding >> Device Tree node for the bridge device, or one of its ancestors. >> This patch adds support for applying a DMA coherent dma_ops for >> PCI devices in the case of such a property. >> >> Signed-off-by: Jon Masters <jcm@redhat.com> >> [added search for device with of_node] >> Signed-off-by: Mark Salter <msalter@redhat.com> >> --- >> arch/arm64/mm/dma-mapping.c | 21 +++++++++++++++++++-- >> 1 file changed, 19 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c >> index 4164c5a..0e26bd7 100644 >> --- a/arch/arm64/mm/dma-mapping.c >> +++ b/arch/arm64/mm/dma-mapping.c >> @@ -23,10 +23,12 @@ >> #include <linux/dma-mapping.h> >> #include <linux/dma-contiguous.h> >> #include <linux/of.h> >> +#include <linux/of_address.h> >> #include <linux/platform_device.h> >> #include <linux/vmalloc.h> >> #include <linux/swiotlb.h> >> #include <linux/amba/bus.h> >> +#include <linux/pci.h> >> >> #include <asm/cacheflush.h> >> >> @@ -316,8 +318,18 @@ static int dma_bus_notifier(struct notifier_block *nb, >> if (event != BUS_NOTIFY_ADD_DEVICE) >> return NOTIFY_DONE; >> >> - if (of_property_read_bool(dev->of_node, "dma-coherent")) >> - set_dma_ops(dev, &coherent_swiotlb_dma_ops); >> + /* >> + * Some devices won't have an of_node but a bus controller/bridge will. >> + * Search up the device chain until we find an of_node to check. >> + */ >> + while (dev) { >> + if (dev->of_node) { >> + if (of_dma_is_coherent(dev->of_node)) >> + set_dma_ops(_dev, &coherent_swiotlb_dma_ops); >> + break; >> + } >> + dev = dev->parent; >> + } > > Hmm, how does this interact with of_dma_configure? I don't think the > dma-coherent property is inherited there, so I'm uneasy about doing this for > buses other than PCI (i.e. the platform bus). > > In other words, we should move to using of_dma_configure for the platform > and amba buses, and have a separate notifier for the PCI bus. Is it likely > that people will have a mixture of coherent and non-coherent devices behind > the same host controller? Right. My original internal patch had a separate method for the PCI bus rather than rolling these back into one...but I suggested to Mark that I thought Catalin and you wanted this rolled back into one. If you'd rather there be two, well that's really easy as we know that works. Jon. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On Fri, 2014-09-19 at 17:28 +0100, Will Deacon wrote: > On Fri, Sep 19, 2014 at 04:51:26PM +0100, Mark Salter wrote: > > The default dma_ops for devices on arm64 systems are noncoherent in > > nature and rely upon special operations and bounce buffers to > > perform a device DMA operation to/from memory. Some drivers rely > > upon coherent operations involving suitably capable hardware. In > > this case, a "dma-coherent" property will exist on the corresponding > > Device Tree node for the bridge device, or one of its ancestors. > > This patch adds support for applying a DMA coherent dma_ops for > > PCI devices in the case of such a property. > > > > Signed-off-by: Jon Masters <jcm@redhat.com> > > [added search for device with of_node] > > Signed-off-by: Mark Salter <msalter@redhat.com> > > --- > > arch/arm64/mm/dma-mapping.c | 21 +++++++++++++++++++-- > > 1 file changed, 19 insertions(+), 2 deletions(-) > > > > diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c > > index 4164c5a..0e26bd7 100644 > > --- a/arch/arm64/mm/dma-mapping.c > > +++ b/arch/arm64/mm/dma-mapping.c > > @@ -23,10 +23,12 @@ > > #include <linux/dma-mapping.h> > > #include <linux/dma-contiguous.h> > > #include <linux/of.h> > > +#include <linux/of_address.h> > > #include <linux/platform_device.h> > > #include <linux/vmalloc.h> > > #include <linux/swiotlb.h> > > #include <linux/amba/bus.h> > > +#include <linux/pci.h> > > > > #include <asm/cacheflush.h> > > > > @@ -316,8 +318,18 @@ static int dma_bus_notifier(struct notifier_block *nb, > > if (event != BUS_NOTIFY_ADD_DEVICE) > > return NOTIFY_DONE; > > > > - if (of_property_read_bool(dev->of_node, "dma-coherent")) > > - set_dma_ops(dev, &coherent_swiotlb_dma_ops); > > + /* > > + * Some devices won't have an of_node but a bus controller/bridge will. > > + * Search up the device chain until we find an of_node to check. > > + */ > > + while (dev) { > > + if (dev->of_node) { > > + if (of_dma_is_coherent(dev->of_node)) > > + set_dma_ops(_dev, &coherent_swiotlb_dma_ops); > > + break; > > + } > > + dev = dev->parent; > > + } > > Hmm, how does this interact with of_dma_configure? I don't think the > dma-coherent property is inherited there, so I'm uneasy about doing this for > buses other than PCI (i.e. the platform bus). of_dma_configure() only gets called for platform bus and it uses of_dma_is_coherent() which searches device ancestors for dma-coherent property. But it uses set_arch_dma_coherent_ops() which is a no-op on arm64 now. Catalin mentions this in another thread: https://lkml.org/lkml/2014/9/15/363 So maybe we should fix set_arch_dma_coherent_ops() and drop platform bus from the notifier handler. > > In other words, we should move to using of_dma_configure for the platform > and amba buses, and have a separate notifier for the PCI bus. Is it likely > that people will have a mixture of coherent and non-coherent devices behind > the same host controller? > > Will > > > return NOTIFY_OK; > > } > > @@ -330,6 +342,10 @@ static struct notifier_block amba_bus_nb = { > > .notifier_call = dma_bus_notifier, > > }; > > > > +static struct notifier_block pci_bus_nb = { > > + .notifier_call = dma_bus_notifier, > > +}; > > + > > extern int swiotlb_late_init_with_default_size(size_t default_size); > > > > static int __init swiotlb_late_init(void) > > @@ -341,6 +357,7 @@ static int __init swiotlb_late_init(void) > > */ > > bus_register_notifier(&platform_bus_type, &platform_bus_nb); > > bus_register_notifier(&amba_bustype, &amba_bus_nb); > > + bus_register_notifier(&pci_bus_type, &pci_bus_nb); > > > > dma_ops = &noncoherent_swiotlb_dma_ops; > > > > -- > > 1.9.3 > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On Fri, Sep 19, 2014 at 04:51:26PM +0100, Mark Salter wrote: > diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c > index 4164c5a..0e26bd7 100644 [...] > @@ -316,8 +318,18 @@ static int dma_bus_notifier(struct notifier_block *nb, > if (event != BUS_NOTIFY_ADD_DEVICE) > return NOTIFY_DONE; > > - if (of_property_read_bool(dev->of_node, "dma-coherent")) > - set_dma_ops(dev, &coherent_swiotlb_dma_ops); > + /* > + * Some devices won't have an of_node but a bus controller/bridge will. > + * Search up the device chain until we find an of_node to check. > + */ > + while (dev) { > + if (dev->of_node) { > + if (of_dma_is_coherent(dev->of_node)) > + set_dma_ops(_dev, &coherent_swiotlb_dma_ops); > + break; > + } > + dev = dev->parent; > + } > > return NOTIFY_OK; > } For AMBA (with an additional patch) and platform devices, we can do the same as ARM and rely on set_arch_dma_coherent_ops(), so most of the notifier code removed. So we leave the above notifier for PCI only. > static int __init swiotlb_late_init(void) > @@ -341,6 +357,7 @@ static int __init swiotlb_late_init(void) > */ > bus_register_notifier(&platform_bus_type, &platform_bus_nb); > bus_register_notifier(&amba_bustype, &amba_bus_nb); > + bus_register_notifier(&pci_bus_type, &pci_bus_nb); Does this compile when CONFIG_PCI is disabled?
On Mon, 2014-09-22 at 11:23 +0100, Catalin Marinas wrote: > > static int __init swiotlb_late_init(void) > > @@ -341,6 +357,7 @@ static int __init swiotlb_late_init(void) > > */ > > bus_register_notifier(&platform_bus_type, &platform_bus_nb); > > bus_register_notifier(&amba_bustype, &amba_bus_nb); > > + bus_register_notifier(&pci_bus_type, &pci_bus_nb); > > Does this compile when CONFIG_PCI is disabled? No. Doh! -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index 4164c5a..0e26bd7 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -23,10 +23,12 @@ #include <linux/dma-mapping.h> #include <linux/dma-contiguous.h> #include <linux/of.h> +#include <linux/of_address.h> #include <linux/platform_device.h> #include <linux/vmalloc.h> #include <linux/swiotlb.h> #include <linux/amba/bus.h> +#include <linux/pci.h> #include <asm/cacheflush.h> @@ -316,8 +318,18 @@ static int dma_bus_notifier(struct notifier_block *nb, if (event != BUS_NOTIFY_ADD_DEVICE) return NOTIFY_DONE; - if (of_property_read_bool(dev->of_node, "dma-coherent")) - set_dma_ops(dev, &coherent_swiotlb_dma_ops); + /* + * Some devices won't have an of_node but a bus controller/bridge will. + * Search up the device chain until we find an of_node to check. + */ + while (dev) { + if (dev->of_node) { + if (of_dma_is_coherent(dev->of_node)) + set_dma_ops(_dev, &coherent_swiotlb_dma_ops); + break; + } + dev = dev->parent; + } return NOTIFY_OK; } @@ -330,6 +342,10 @@ static struct notifier_block amba_bus_nb = { .notifier_call = dma_bus_notifier, }; +static struct notifier_block pci_bus_nb = { + .notifier_call = dma_bus_notifier, +}; + extern int swiotlb_late_init_with_default_size(size_t default_size); static int __init swiotlb_late_init(void) @@ -341,6 +357,7 @@ static int __init swiotlb_late_init(void) */ bus_register_notifier(&platform_bus_type, &platform_bus_nb); bus_register_notifier(&amba_bustype, &amba_bus_nb); + bus_register_notifier(&pci_bus_type, &pci_bus_nb); dma_ops = &noncoherent_swiotlb_dma_ops;