soc/intel/common/lpss: Add function to check for a LPSS controller

Add an API to check if device is a LPSS controller. This API can be
used for IRQ assignments for LPSS PCI controllers, since the LPSS
controllers have a requirement of unique IRQ assignments and do not
share same IRQ# with other LPSS controllers.

SOC code is reponsible to provide list of the LPSS controllers
supported and needs to implement soc_lpss_controllers_list API,
in case it needs to use this common implementation.

Change-Id: I3f5bb268fc581280bb1b87b6b175a0299a24a44a
Signed-off-by: Aamir Bohra <aamir.bohra@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34137
Reviewed-by: Paul Fagerburg <pfagerburg@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/common/block/include/intelblocks/lpss.h

@@ -40,4 +40,13 @@ bool lpss_is_controller_in_reset(uintptr_t base);
 /* Set controller power state to D0 or D3*/
 void lpss_set_power_state(const struct device *dev, enum lpss_pwr_state state);
 
+/*
+ * Handler to get list of LPSS controllers. The SOC is expected to send out a
+ * list of pci devfn for all LPSS controllers supported by the SOC.
+ */
+const pci_devfn_t *soc_lpss_controllers_list(size_t *size);
+
+/* Check if the device is a LPSS controller */
+bool is_dev_lpss(const struct device *dev);
+
 #endif	/* SOC_INTEL_COMMON_BLOCK_LPSS_H */

src/soc/intel/common/block/lpss/lpss.c

@@ -89,3 +89,21 @@ void lpss_set_power_state(const struct device *dev, enum lpss_pwr_state state)
 
 	pci_update_config8(lpss_dev, PME_CTRL_STATUS, ~POWER_STATE_MASK, state);
 }
+
+bool is_dev_lpss(const struct device *dev)
+{
+	static size_t size;
+	static const pci_devfn_t *lpss_devices;
+
+	if (dev->path.type != DEVICE_PATH_PCI)
+		return false;
+
+	if (!lpss_devices)
+		lpss_devices = soc_lpss_controllers_list(&size);
+
+	for (int i = 0; i < size; i++) {
+		if (lpss_devices[i] == dev->path.pci.devfn)
+			return true;
+	}
+	return false;
+}