PCI: Assign bus numbers present in EA capability for bridges (2dbce590) · Commits · 戴 / test

drivers/pci/probe.c

+50 −4

Original line number	Diff line number	Diff line
		@@ -1086,6 +1086,36 @@ static void pci_enable_crs(struct pci_dev *pdev)

		static unsigned int pci_scan_child_bus_extend(struct pci_bus *bus,
		unsigned int available_buses);
		/**
		* pci_ea_fixed_busnrs() - Read fixed Secondary and Subordinate bus
		* numbers from EA capability.
		* @dev: Bridge
		* @sec: updated with secondary bus number from EA
		* @sub: updated with subordinate bus number from EA
		*
		* If @dev is a bridge with EA capability, update @sec and @sub with
		* fixed bus numbers from the capability and return true. Otherwise,
		* return false.
		*/
		static bool pci_ea_fixed_busnrs(struct pci_dev dev, u8 sec, u8 *sub)
		{
		int ea, offset;
		u32 dw;

		if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE)
		return false;

		/* find PCI EA capability in list */
		ea = pci_find_capability(dev, PCI_CAP_ID_EA);
		if (!ea)
		return false;

		offset = ea + PCI_EA_FIRST_ENT;
		pci_read_config_dword(dev, offset, &dw);
		*sec = dw & PCI_EA_SEC_BUS_MASK;
		*sub = (dw & PCI_EA_SUB_BUS_MASK) >> PCI_EA_SUB_BUS_SHIFT;
		return true;
		}

		/*
		* pci_scan_bridge_extend() - Scan buses behind a bridge
		@@ -1120,6 +1150,9 @@ static int pci_scan_bridge_extend(struct pci_bus bus, struct pci_dev dev,
		u16 bctl;
		u8 primary, secondary, subordinate;
		int broken = 0;
		bool fixed_buses;
		u8 fixed_sec, fixed_sub;
		int next_busnr;

		/*
		* Make sure the bridge is powered on to be able to access config
		@@ -1219,17 +1252,24 @@ static int pci_scan_bridge_extend(struct pci_bus bus, struct pci_dev dev,
		/* Clear errors */
		pci_write_config_word(dev, PCI_STATUS, 0xffff);

		/* Read bus numbers from EA Capability (if present) */
		fixed_buses = pci_ea_fixed_busnrs(dev, &fixed_sec, &fixed_sub);
		if (fixed_buses)
		next_busnr = fixed_sec;
		else
		next_busnr = max + 1;

		/*
		* Prevent assigning a bus number that already exists.
		* This can happen when a bridge is hot-plugged, so in this
		* case we only re-scan this bus.
		*/
		child = pci_find_bus(pci_domain_nr(bus), max+1);
		child = pci_find_bus(pci_domain_nr(bus), next_busnr);
		if (!child) {
		child = pci_add_new_bus(bus, dev, max+1);
		child = pci_add_new_bus(bus, dev, next_busnr);
		if (!child)
		goto out;
		pci_bus_insert_busn_res(child, max+1,
		pci_bus_insert_busn_res(child, next_busnr,
		bus->busn_res.end);
		}
		max++;
		@@ -1290,7 +1330,13 @@ static int pci_scan_bridge_extend(struct pci_bus bus, struct pci_dev dev,
		max += i;
		}

		/* Set subordinate bus number to its real value */
		/*
		* Set subordinate bus number to its real value.
		* If fixed subordinate bus number exists from EA
		* capability then use it.
		*/
		if (fixed_buses)
		max = fixed_sub;
		pci_bus_update_busn_res_end(child, max);
		pci_write_config_byte(dev, PCI_SUBORDINATE_BUS, max);
		}

include/uapi/linux/pci_regs.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -372,6 +372,12 @@
		#define PCI_EA_FIRST_ENT_BRIDGE 8 /* First EA Entry for Bridges */
		#define PCI_EA_ES 0x00000007 /* Entry Size */
		#define PCI_EA_BEI 0x000000f0 /* BAR Equivalent Indicator */

		/* EA fixed Secondary and Subordinate bus numbers for Bridge */
		#define PCI_EA_SEC_BUS_MASK 0xff
		#define PCI_EA_SUB_BUS_MASK 0xff00
		#define PCI_EA_SUB_BUS_SHIFT 8

		/* 0-5 map to BARs 0-5 respectively */
		#define PCI_EA_BEI_BAR0 0
		#define PCI_EA_BEI_BAR5 5

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