Hi Chen,
On top of Bjorn's comments:
On 2020-11-17 13:42, Chen Baozi wrote:
Some PCIe designs require software to do extra acknowledgements for
legacy INTx interrupts. If the driver is written only for device tree,
things are simple. In that case, a new driver can be written under
driver/pci/controller/ with a DT node of PCIe host written like:
pcie {
...
interrupt-map = <0 0 0 1 &pcie_intc 0>,
<0 0 0 2 &pcie_intc 1>,
<0 0 0 3 &pcie_intc 2>,
<0 0 0 4 &pcie_intc 3>;
pcie_intc: legacy-interrupt-controller {
interrupt-controller;
#interrupt-cells = <1>;
interrupt-parent = <&gic>;
interrupts = <0 226 4>;
};
};
Similar designs can be found on Aardvark, MediaTek Gen2 and Socionext
UniPhier PCIe controller at the moment. Essentially, those designs are
supported by inserting an extra interrupt controller between PCIe host
and GIC and parse the topology in a DT-based PCI controller driver.
As we turn to ACPI, All the PCIe hosts are described the same ID of
"PNP0A03" and share driver/acpi/pci_root.c. It comes to be a problem
to make this kind of PCI INTx work under ACPI.
Therefore, we introduce an stacked IRQ domain support to PCI interrupt
link for ACPI. With this support, we can populate the ResourceSource
to refer to a device object that describes an interrupt controller.
That would allow us to refer to a dedicated driver which implements
the logic needed to manage the interrupt state. With this patch,
those PCI interrupt links can be supported by describing the INTx
in ACPI table as the following example:
Device (IXIU) {
...
}
Device(LINKA) {
Name(_HID, EISAID("PNP0C0F"))
Name(_PRS, ResourceTemplate(){
Interrupt(ResourceProducer, Level, ActiveHigh, Exclusive, 0,
"\\SB.IXIU")
{ 60 }
})
...
}
Device(PCI0) {
...
Name(_PRT, Package{
Package{ 0x0000FFFF, 0, LINKA, 0 }
...
})
}
Signed-off-by: Chen Baozi <chenbaozi@xxxxxxxxxxxxxx>
---
drivers/acpi/irq.c | 22 +++++++++++++++++++++-
drivers/acpi/pci_irq.c | 6 ++++--
drivers/acpi/pci_link.c | 17 +++++++++++++++--
include/acpi/acpi_drivers.h | 2 +-
include/linux/acpi.h | 4 ++++
5 files changed, 45 insertions(+), 6 deletions(-)
diff --git a/drivers/acpi/irq.c b/drivers/acpi/irq.c
index e209081d644b..e78a44815c44 100644
--- a/drivers/acpi/irq.c
+++ b/drivers/acpi/irq.c
@@ -81,6 +81,25 @@ void acpi_unregister_gsi(u32 gsi)
}
EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
+int acpi_register_irq(struct device *dev, u32 irq, int trigger,
+ int polarity, struct fwnode_handle *domain_id)
+{
+ struct irq_fwspec fwspec;
+
+ if (WARN_ON(!domain_id)) {
+ pr_warn("GSI: No registered irqchip, giving up\n");
A fwnode_handle is not an irqchip. It's just an opaque identifier
for a HW block. Furthermore, there is no need to have both a WARN_ON()
and a pr_warn(). Please pick one.
I'd also suggest you rename domain_id to fwnode, which is the commonly
used idiom (yes, I know about the unfortunate precedent in
acpi_register_gsi()).
+ return -EINVAL;
+ }
+
+ fwspec.fwnode = domain_id;
+ fwspec.param[0] = irq;
+ fwspec.param[1] = acpi_dev_get_irq_type(trigger, polarity);
+ fwspec.param_count = 2;
+
+ return irq_create_fwspec_mapping(&fwspec);
+}
+EXPORT_SYMBOL_GPL(acpi_register_irq);
By the way, this is almost an exact duplicate of acpi_register_gsi().
You definitely want to make this code common.
+
/**
* acpi_get_irq_source_fwhandle() - Retrieve fwhandle from IRQ
resource source.
* @source: acpi_resource_source to use for the lookup.
@@ -92,7 +111,7 @@ EXPORT_SYMBOL_GPL(acpi_unregister_gsi);
* Return:
* The referenced device fwhandle or NULL on failure
*/
-static struct fwnode_handle *
+struct fwnode_handle *
acpi_get_irq_source_fwhandle(const struct acpi_resource_source
*source)
{
struct fwnode_handle *result;
@@ -115,6 +134,7 @@ acpi_get_irq_source_fwhandle(const struct
acpi_resource_source *source)
acpi_bus_put_acpi_device(device);
return result;
}
+EXPORT_SYMBOL_GPL(acpi_get_irq_source_fwhandle);
/*
* Context for the resource walk used to lookup IRQ resources.
diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
index 14ee631cb7cf..19296d70c95c 100644
--- a/drivers/acpi/pci_irq.c
+++ b/drivers/acpi/pci_irq.c
@@ -410,6 +410,7 @@ int acpi_pci_irq_enable(struct pci_dev *dev)
char *link = NULL;
char link_desc[16];
int rc;
+ struct fwnode_handle *irq_domain;
fwnode_handle is most definitely not an IRQ domain.
pin = dev->pin;
if (!pin) {
@@ -438,7 +439,8 @@ int acpi_pci_irq_enable(struct pci_dev *dev)
gsi = acpi_pci_link_allocate_irq(entry->link,
entry->index,
&triggering, &polarity,
- &link);
+ &link,
+ &irq_domain);
else
gsi = entry->index;
} else
@@ -462,7 +464,7 @@ int acpi_pci_irq_enable(struct pci_dev *dev)
return 0;
}
- rc = acpi_register_gsi(&dev->dev, gsi, triggering, polarity);
+ rc = acpi_register_irq(&dev->dev, gsi, triggering, polarity,
irq_domain);
if (rc < 0) {
dev_warn(&dev->dev, "PCI INT %c: failed to register GSI\n",
pin_name(pin));
diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
index fb4c5632a232..219a644d739a 100644
--- a/drivers/acpi/pci_link.c
+++ b/drivers/acpi/pci_link.c
@@ -59,6 +59,7 @@ struct acpi_pci_link_irq {
u8 resource_type;
u8 possible_count;
u32 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
+ struct acpi_resource_source resource_source;
u8 initialized:1;
u8 reserved:7;
};
@@ -120,6 +121,8 @@ static acpi_status
acpi_pci_link_check_possible(struct acpi_resource *resource,
{
struct acpi_resource_extended_irq *p =
&resource->data.extended_irq;
+ struct acpi_resource_source *rs =
+ &link->irq.resource_source;
if (!p || !p->interrupt_count) {
printk(KERN_WARNING PREFIX
"Blank _PRS EXT IRQ resource\n");
@@ -140,6 +143,12 @@ static acpi_status
acpi_pci_link_check_possible(struct acpi_resource *resource,
link->irq.triggering = p->triggering;
link->irq.polarity = p->polarity;
link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
+ if (p->resource_source.string_length) {
+ rs->index = p->resource_source.index;
+ rs->string_length = p->resource_source.string_length;
+ rs->string_ptr = kmalloc(rs->string_length, GFP_KERNEL);
+ strcpy(rs->string_ptr, p->resource_source.string_ptr);
We have kstrdup() for this kind of things, as using rs->string_length to
allocate
the buffer and strcpy() to copy it feels... dangerous.
+ }
break;
}
default:
@@ -326,7 +335,8 @@ static int acpi_pci_link_set(struct acpi_pci_link
*link, int irq)
resource->res.data.extended_irq.shareable = ACPI_SHARED;
resource->res.data.extended_irq.interrupt_count = 1;
resource->res.data.extended_irq.interrupts[0] = irq;
- /* ignore resource_source, it's optional */
+ resource->res.data.extended_irq.resource_source =
+ link->irq.resource_source;
break;
default:
printk(KERN_ERR PREFIX "Invalid Resource_type %d\n",
link->irq.resource_type);
@@ -612,7 +622,7 @@ static int acpi_pci_link_allocate(struct
acpi_pci_link *link)
* failure: return -1
*/
int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int
*triggering,
- int *polarity, char **name)
+ int *polarity, char **name, struct fwnode_handle
**irq_domain)
Same remark about the naming.
{
int result;
struct acpi_device *device;
@@ -656,6 +666,9 @@ int acpi_pci_link_allocate_irq(acpi_handle handle,
int index, int *triggering,
*polarity = link->irq.polarity;
if (name)
*name = acpi_device_bid(link->device);
+ if (irq_domain)
+ *irq_domain =
acpi_get_irq_source_fwhandle(&link->irq.resource_source);
+
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Link %s is referenced\n",
acpi_device_bid(link->device)));
diff --git a/include/acpi/acpi_drivers.h b/include/acpi/acpi_drivers.h
index 5eb175933a5b..6ff1ea76d476 100644
--- a/include/acpi/acpi_drivers.h
+++ b/include/acpi/acpi_drivers.h
@@ -68,7 +68,7 @@
int acpi_irq_penalty_init(void);
int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int
*triggering,
- int *polarity, char **name);
+ int *polarity, char **name, struct fwnode_handle
**irq_domain);
int acpi_pci_link_free_irq(acpi_handle handle);
/* ACPI PCI Device Binding (pci_bind.c) */
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 39263c6b52e1..5f1d7d3192fb 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -324,6 +324,8 @@ extern int sbf_port;
extern unsigned long acpi_realmode_flags;
int acpi_register_gsi (struct device *dev, u32 gsi, int triggering,
int polarity);
+int acpi_register_irq(struct device *dev, u32 gsi, int trigger,
+ int polarity, struct fwnode_handle *domain_id);
int acpi_gsi_to_irq (u32 gsi, unsigned int *irq);
int acpi_isa_irq_to_gsi (unsigned isa_irq, u32 *gsi);
@@ -336,6 +338,8 @@ struct irq_domain
*acpi_irq_create_hierarchy(unsigned int flags,
const struct irq_domain_ops *ops,
void *host_data);
+struct fwnode_handle *acpi_get_irq_source_fwhandle(const struct
acpi_resource_source *source);
+
#ifdef CONFIG_X86_IO_APIC
extern int acpi_get_override_irq(u32 gsi, int *trigger, int
*polarity);
#else
Thanks,
M.
--
Jazz is not dead. It just smells funny...
