PCI devices on Keystone doesn't have correct dma_pfn_offset set. This patch
add capability to set the dma configuration such as dma-mask, dma_pfn_offset,
and dma ops etc using the information from DT. The prior RFCs and discussions
are available at [1] and [2] below.
[2] : https://www.mail-archive.com/[email protected]/msg790244.html
[1] : http://www.gossamer-threads.com/lists/linux/kernel/2024591
Change history:
v2 - update size to coherent_dma_mask + 1 if dma-range info is missing
- also check the np for null.
v1 - updates based on the comments against initial RFC.
- Added a helper function to get the OF node of the parent
- Added an API in of_pci.c to update DMA configuration of the pci
device.
Murali Karicheri (2):
of/pci: add of_pci_dma_configure() update dma configuration
PCI: update dma configuration from DT
drivers/of/of_pci.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++
drivers/pci/probe.c | 2 ++
include/linux/of_pci.h | 12 ++++++++
3 files changed, 87 insertions(+)
--
1.7.9.5
If there is a DT node available for the root bridge's parent device,
use the dma configuration from that device node. For example, keystone
PCI devices would require dma_pfn_offset to be set correctly in the
device structure of the pci device in order to have the correct dma mask.
The DT node will have dma-ranges defined for this. Also support using
the DT property dma-coherent to allow coherent DMA operation by the
PCI device.
This patch use the new helper function of_pci_dma_configure() to update
the device dma configuration.
Signed-off-by: Murali Karicheri <[email protected]>
---
drivers/pci/probe.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 23212f8..d7dcd6c 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -6,6 +6,7 @@
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/pci.h>
+#include <linux/of_pci.h>
#include <linux/pci_hotplug.h>
#include <linux/slab.h>
#include <linux/module.h>
@@ -1520,6 +1521,7 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
dev->dev.dma_mask = &dev->dma_mask;
dev->dev.dma_parms = &dev->dma_parms;
dev->dev.coherent_dma_mask = 0xffffffffull;
+ of_pci_dma_configure(dev);
pci_set_dma_max_seg_size(dev, 65536);
pci_set_dma_seg_boundary(dev, 0xffffffff);
--
1.7.9.5
Add of_pci_dma_configure() to allow updating the dma configuration
of the pci device using the configuration from DT of the parent of
the root bridge device.
Signed-off-by: Murali Karicheri <[email protected]>
---
drivers/of/of_pci.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_pci.h | 12 ++++++++
2 files changed, 85 insertions(+)
diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 88471d3..6d43f59 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -229,6 +229,79 @@ parse_failed:
return err;
}
EXPORT_SYMBOL_GPL(of_pci_get_host_bridge_resources);
+
+/**
+ * of_get_pci_root_bridge_parent - Helper function to get the OF node of
+ * the root bridge's parent
+ * @dev: ptr to pci_dev struct of the pci device
+ *
+ * This function will traverse the bus up to the root bus starting with
+ * the child and return the of node ptr to bridge device's parent device.
+ */
+struct device_node *of_get_pci_root_bridge_parent(struct pci_dev *dev)
+{
+ struct pci_bus *bus = dev->bus;
+ struct device *bridge;
+
+ while (!pci_is_root_bus(bus))
+ bus = bus->parent;
+ bridge = bus->bridge;
+
+ return bridge->parent->of_node;
+}
+EXPORT_SYMBOL_GPL(of_get_pci_root_bridge_parent);
+
+/**
+ * of_pci_dma_configure - Setup DMA configuration
+ * @dev: ptr to pci_dev struct of the pci device
+ *
+ * Try to get PCI devices's DMA configuration from DT and update it
+ * accordingly. This is similar to of_dma_configure() in of/platform.c
+ */
+void of_pci_dma_configure(struct pci_dev *pci_dev)
+{
+ struct device *dev = &pci_dev->dev;
+ u64 dma_addr, paddr, size;
+ struct device_node *parent_np;
+ unsigned long offset;
+ bool coherent;
+ int ret;
+
+ parent_np = of_get_pci_root_bridge_parent(pci_dev);
+
+ if (parent_np) {
+ /*
+ * Set default dma-mask to 32 bit. Drivers are expected to setup
+ * the correct supported dma_mask.
+ */
+ dev->coherent_dma_mask = DMA_BIT_MASK(32);
+
+ /*
+ * Set it to coherent_dma_mask by default if the architecture
+ * code has not set it.
+ */
+ if (!dev->dma_mask)
+ dev->dma_mask = &dev->coherent_dma_mask;
+
+ ret = of_dma_get_range(parent_np, &dma_addr, &paddr, &size);
+ if (ret < 0) {
+ dma_addr = offset = 0;
+ size = dev->coherent_dma_mask + 1;
+ } else {
+ offset = PFN_DOWN(paddr - dma_addr);
+ dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
+ }
+ dev->dma_pfn_offset = offset;
+
+ coherent = of_dma_is_coherent(parent_np);
+ dev_dbg(dev, "device is%sdma coherent\n",
+ coherent ? " " : " not ");
+
+ arch_setup_dma_ops(dev, dma_addr, size, NULL, coherent);
+ }
+}
+EXPORT_SYMBOL_GPL(of_pci_dma_configure);
+
#endif /* CONFIG_OF_ADDRESS */
#ifdef CONFIG_PCI_MSI
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index ce0e5ab..0465a2a 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -16,6 +16,8 @@ int of_pci_get_devfn(struct device_node *np);
int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin);
int of_pci_parse_bus_range(struct device_node *node, struct resource *res);
int of_get_pci_domain_nr(struct device_node *node);
+struct device_node *of_get_pci_root_bridge_parent(struct pci_dev *dev);
+void of_pci_dma_configure(struct pci_dev *pci_dev);
#else
static inline int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
{
@@ -50,6 +52,16 @@ of_get_pci_domain_nr(struct device_node *node)
{
return -1;
}
+
+static inline struct device_node
+*of_get_pci_root_bridge_parent(struct pci_dev *dev)
+{
+ return NULL;
+}
+
+static inline void of_pci_dma_configure(struct pci_dev *pci_dev)
+{
+}
#endif
#if defined(CONFIG_OF_ADDRESS)
--
1.7.9.5
On Wed, Dec 24, 2014 at 4:11 PM, Murali Karicheri <[email protected]> wrote:
> Add of_pci_dma_configure() to allow updating the dma configuration
> of the pci device using the configuration from DT of the parent of
> the root bridge device.
>
> Signed-off-by: Murali Karicheri <[email protected]>
> ---
> drivers/of/of_pci.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/of_pci.h | 12 ++++++++
> 2 files changed, 85 insertions(+)
>
> diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
> index 88471d3..6d43f59 100644
> --- a/drivers/of/of_pci.c
> +++ b/drivers/of/of_pci.c
> @@ -229,6 +229,79 @@ parse_failed:
> return err;
> }
> EXPORT_SYMBOL_GPL(of_pci_get_host_bridge_resources);
> +
> +/**
> + * of_get_pci_root_bridge_parent - Helper function to get the OF node of
> + * the root bridge's parent
I believe this has to be a one line description for DocBook.
> + * @dev: ptr to pci_dev struct of the pci device
> + *
> + * This function will traverse the bus up to the root bus starting with
> + * the child and return the of node ptr to bridge device's parent device.
> + */
> +struct device_node *of_get_pci_root_bridge_parent(struct pci_dev *dev)
> +{
> + struct pci_bus *bus = dev->bus;
> + struct device *bridge;
> +
> + while (!pci_is_root_bus(bus))
> + bus = bus->parent;
> + bridge = bus->bridge;
> +
> + return bridge->parent->of_node;
> +}
> +EXPORT_SYMBOL_GPL(of_get_pci_root_bridge_parent);
> +
> +/**
> + * of_pci_dma_configure - Setup DMA configuration
> + * @dev: ptr to pci_dev struct of the pci device
> + *
> + * Try to get PCI devices's DMA configuration from DT and update it
> + * accordingly. This is similar to of_dma_configure() in of/platform.c
> + */
> +void of_pci_dma_configure(struct pci_dev *pci_dev)
> +{
> + struct device *dev = &pci_dev->dev;
> + u64 dma_addr, paddr, size;
> + struct device_node *parent_np;
> + unsigned long offset;
> + bool coherent;
> + int ret;
> +
> + parent_np = of_get_pci_root_bridge_parent(pci_dev);
> +
> + if (parent_np) {
Save a level of indentation and do:
if (!parent_np)
return;
> + /*
> + * Set default dma-mask to 32 bit. Drivers are expected to setup
> + * the correct supported dma_mask.
> + */
> + dev->coherent_dma_mask = DMA_BIT_MASK(32);
> +
> + /*
> + * Set it to coherent_dma_mask by default if the architecture
> + * code has not set it.
> + */
> + if (!dev->dma_mask)
> + dev->dma_mask = &dev->coherent_dma_mask;
> +
> + ret = of_dma_get_range(parent_np, &dma_addr, &paddr, &size);
> + if (ret < 0) {
> + dma_addr = offset = 0;
> + size = dev->coherent_dma_mask + 1;
> + } else {
> + offset = PFN_DOWN(paddr - dma_addr);
> + dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
> + }
> + dev->dma_pfn_offset = offset;
> +
> + coherent = of_dma_is_coherent(parent_np);
> + dev_dbg(dev, "device is%sdma coherent\n",
> + coherent ? " " : " not ");
> +
> + arch_setup_dma_ops(dev, dma_addr, size, NULL, coherent);
This is the same code as of_dma_configure. The only difference I see
is which node ptr is passed to of_dma_get_range. You need to make that
a function param of of_dma_configure.
of_dma_configure also has iommu handling now. You will probably need
something similar for PCI in that you setup an iommu based on the root
bus DT properties.
Rob