On 02.01.2017 14:31, Hanjun Guo wrote:
For devices connecting to ITS, it needs dev id to identify
itself, and this dev id is represented in the IORT table in
named componant node [1] for platform devices, so in this
patch we will scan the IORT to retrieve device's dev id.

Introduce iort_pmsi_get_dev_id() with pointer dev passed
in for that purpose.

[1]: https://static.docs.arm.com/den0049/b/DEN0049B_IO_Remapping_Table.pdf

Signed-off-by: Hanjun Guo <[email protected]>
Tested-by: Sinan Kaya <[email protected]>
Tested-by: Majun <[email protected]>
Tested-by: Xinwei Kong <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Lorenzo Pieralisi <[email protected]>
Cc: Tomasz Nowicki <[email protected]>
Cc: Thomas Gleixner <[email protected]>
---
 drivers/acpi/arm64/iort.c                     | 26 ++++++++++++++++++++++++++
 drivers/irqchip/irq-gic-v3-its-platform-msi.c |  4 +++-
 include/linux/acpi_iort.h                     |  8 ++++++++
 3 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 174e983..ab7bae7 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -444,6 +444,32 @@ u32 iort_msi_map_rid(struct device *dev, u32 req_id)
 }

 /**
+ * iort_pmsi_get_dev_id() - Get the device id for a device
+ * @dev: The device for which the mapping is to be done.
+ * @dev_id: The device ID found.
+ *
+ * Returns: 0 for successful find a dev id, errors otherwise
+ */
+int iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id)
+{
+       struct acpi_iort_node *node;
+
+       if (!iort_table)
+               return -ENODEV;
+
+       node = iort_find_dev_node(dev);
+       if (!node) {
+               dev_err(dev, "can't find related IORT node\n");
+               return -ENODEV;
+       }
+
+       if(!iort_node_get_id(node, dev_id, IORT_MSI_TYPE, 0))
+               return -ENODEV;
+
+       return 0;
+}
+
+/**
Giving that you are extending this to NC->
SMMU->ITS case in later patch, we can use existing helpers from iort.c, like that:

+/**
+ * iort_pmsi_get_dev_id() - Get the device id for a device
+ * @dev: The device for which the mapping is to be done.
+ * @dev_id: The device ID found.
+ *
+ * Returns: 0 for successful find a dev id, errors otherwise
+ */
+int iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id)
+{
+       struct acpi_iort_node *node;
+
+       node = iort_find_dev_node(dev);
+       if (!node)
+               return -ENODEV;
+
+       if (!iort_node_map_rid(node, 0, dev_id, IORT_MSI_TYPE))
+               return -ENODEV;
+
+       return 0;
+}

Correct me if I am wrong.

Tomasz


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