On Thu, Sep 11, 2014 at 12:08 PM, Grant Likely [off-list ref] wrote:

On Mon,  1 Sep 2014 22:57:49 +0800, Hanjun Guo [off-list ref] wrote:

quoted

Introduce ACPI_IRQ_MODEL_GIC which is needed for ARM64 as GIC is
used, and then register device's gsi with the core IRQ subsystem.

acpi_register_gsi() is similar to DT based irq_of_parse_and_map(),
since gsi is unique in the system, so use hwirq number directly
for the mapping.

Originally-by: Amit Daniel Kachhap [off-list ref]
Signed-off-by: Hanjun Guo <redacted>
---
 arch/arm64/kernel/acpi.c |   73 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/acpi/bus.c       |    3 ++
 include/linux/acpi.h     |    1 +
 3 files changed, 77 insertions(+)

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 35dff11..354b912 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c

@@ -37,6 +37,12 @@ EXPORT_SYMBOL(acpi_pci_disabled);
 static int enabled_cpus;     /* Processors (GICC) with enabled flag in MADT */

 /*
+ * Since we're on ARM, the default interrupt routing model
+ * clearly has to be GIC.
+ */
+enum acpi_irq_model_id acpi_irq_model = ACPI_IRQ_MODEL_GIC;
+
+/*
  * __acpi_map_table() will be called before page_init(), so early_ioremap()
  * or early_memremap() should be called here to for ACPI table mapping.
  */

@@ -194,6 +200,73 @@ void __init acpi_smp_init_cpus(void)
      pr_info("%d CPUs enabled, %d CPUs total\n", enabled_cpus, total_cpus);
 }

+int acpi_gsi_to_irq(u32 gsi, unsigned int *irq)
+{
+     *irq = irq_find_mapping(NULL, gsi);
+
+     return 0;
+}
+EXPORT_SYMBOL_GPL(acpi_gsi_to_irq);

Why is this exported? x86 exports it, but ia64 does not. There aren't
very many callers, and none of them can be built as a module AFAICS.

quoted

+
+/*
+ * success: return IRQ number (>0)
+ * failure: return =< 0
+ */
+int acpi_register_gsi(struct device *dev, u32 gsi, int trigger, int polarity)
+{
+     unsigned int irq;
+     unsigned int irq_type;
+
+     /*
+      * ACPI have no bindings to indicate SPI or PPI, so we
+      * use different mappings from DT in ACPI.
+      *
+      * For FDT
+      * PPI interrupt: in the range [0, 15];
+      * SPI interrupt: in the range [0, 987];
+      *
+      * For ACPI, GSI should be unique so using
+      * the hwirq directly for the mapping:
+      * PPI interrupt: in the range [16, 31];
+      * SPI interrupt: in the range [32, 1019];
+      */

Hmmm, so doing it this way means that DT systems will have a different
irq_domain setup compared with ACPI systems. I'm not convinced we want
to do that, but I need to look at the code that sets up the new domains
before I comment further...

Okay, nevermind. I looked at the setup code. This isn't an issue of
the irq domain being set up differently, but rather the binding
translation operates differently between DT and ACPI. ACPI used a
single integer encapsulating PPI and SPI which just happens to line up
with the hwirq numbers, whereas DT uses a [type,number] tuple that
needs translating into the hwirq. This code is fine.

g.