hw: Introduce platform-specifc MSI function

The platform-specific get_msi_params function returns MSI parameters for
a device identified by PCI config space address. The function returns
false if either the platform or the device does not support MSI mode of
operation.

repos/base-hw/src/core/include/platform.h

@@ -121,6 +121,19 @@ namespace Genode {
 			static void setup_irq_mode(unsigned irq_number, unsigned trigger,
 			                           unsigned polarity);
 
+			/**
+			 * Get MSI-related parameters from device PCI config space
+			 *
+			 * \param mmconf      PCI config space address of device
+			 * \param address     MSI address register value to use
+			 * \param data        MSI data register value to use
+			 * \param irq_number  IRQ to use
+			 *
+			 * \return  true if the device is MSI-capable, false if not
+			 */
+			static bool get_msi_params(const addr_t mmconf,
+			                           addr_t &address, addr_t &data,
+			                           unsigned &irq_number);
 			/**
 			 * Return address of cores translation table allocator
 			 */

repos/base-hw/src/core/irq_session_component.cc

@@ -69,9 +69,15 @@ Irq_session_component::Irq_session_component(Range_allocator * const irq_alloc,
 	_irq_number(Platform::irq(_find_irq_number(args))), _irq_alloc(irq_alloc),
 	_is_msi(false), _address(0), _value(0)
 {
-	long const msi = Arg_string::find_arg(args, "device_config_phys").long_value(0);
-	if (msi)
-		throw Root::Unavailable();
+	const long mmconf =
+		Arg_string::find_arg(args, "device_config_phys").long_value(0);
+
+	if (mmconf) {
+		_is_msi =
+			Platform::get_msi_params(mmconf, _address, _value, _irq_number);
+		if (!_is_msi)
+			throw Root::Unavailable();
+	}
 
 	/* allocate interrupt */
 	if (_irq_alloc->alloc_addr(1, _irq_number).is_error()) {

repos/base-hw/src/core/spec/arm/platform_support.cc

@@ -36,3 +36,10 @@ void Platform::_init_io_mem_alloc()
 
 
 long Platform::irq(long const user_irq) { return user_irq; }
+
+
+bool Platform::get_msi_params(const addr_t mmconf, addr_t &address,
+                              addr_t &data, unsigned &irq_number)
+{
+	return false;
+}

repos/base-hw/src/core/spec/riscv/platform_support.cc

@@ -37,3 +37,9 @@ void Platform::_init_io_mem_alloc() { }
 void Platform::setup_irq_mode(unsigned, unsigned, unsigned) { }
 
 long Platform::irq(long const user_irq) { return 0; }
+
+bool Platform::get_msi_params(const addr_t mmconf, addr_t &address,
+                              addr_t &data, unsigned &irq_number)
+{
+	return false;
+}

repos/base-hw/src/core/spec/x86_64/muen/platform_support.cc

@@ -29,9 +29,17 @@ Native_region * Platform::_core_only_mmio_regions(unsigned const i)
 	return i < sizeof(_regions)/sizeof(_regions[0]) ? &_regions[i] : 0;
 }
 
+
 void Platform::setup_irq_mode(unsigned, unsigned, unsigned) { }
 
 
+bool Platform::get_msi_params(const addr_t mmconf, addr_t &address,
+                              addr_t &data, unsigned &irq_number)
+{
+	return false;
+}
+
+
 Native_region * Platform::_ram_regions(unsigned const i)
 {
 	static Native_region _regions[] =

repos/base-hw/src/core/spec/x86_64/platform_support.cc

@@ -49,6 +49,13 @@ void Platform::setup_irq_mode(unsigned irq_number, unsigned trigger,
 }
 
 
+bool Platform::get_msi_params(const addr_t mmconf, addr_t &address,
+                              addr_t &data, unsigned &irq_number)
+{
+	return false;
+}
+
+
 Native_region * Platform::_ram_regions(unsigned const i)
 {
 	static Native_region _regions[16];