SMCCC/PCI: Add initial PCI conduit definitions

Add constants, structures and build definition for the
new standard SMCCC PCI conduit. These are documented
in DEN0115A.

https://developer.arm.com/documentation/den0115/latest

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Change-Id: If667800a26b9ae88626e8d895674c9c2e8c09658

include/services/pci_svc.h

+/*
+ * Copyright (c) 2021, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef PCI_SVC_H
+#define PCI_SVC_H
+
+#include <lib/utils_def.h>
+
+/* SMCCC PCI platform functions */
+#define SMC_PCI_VERSION			U(0x84000130)
+#define SMC_PCI_FEATURES		U(0x84000131)
+#define SMC_PCI_READ			U(0x84000132)
+#define SMC_PCI_WRITE			U(0x84000133)
+#define SMC_PCI_SEG_INFO		U(0x84000134)
+
+#define is_pci_fid(_fid) (((_fid) >= SMC_PCI_VERSION) &&  \
+			  ((_fid) <= SMC_PCI_SEG_INFO))
+
+uint64_t pci_smc_handler(uint32_t smc_fid, u_register_t x1, u_register_t x2,
+			 u_register_t x3,  u_register_t x4, void *cookie,
+			 void *handle, u_register_t flags);
+
+#define PCI_ADDR_FUN(dev) ((dev) & U(0x7))
+#define PCI_ADDR_DEV(dev) (((dev) >> U(3))  & U(0x001F))
+#define PCI_ADDR_BUS(dev) (((dev) >> U(8))  & U(0x00FF))
+#define PCI_ADDR_SEG(dev) (((dev) >> U(16)) & U(0xFFFF))
+#define PCI_OFFSET_MASK   U(0xFFF)
+typedef union {
+	struct {
+		uint16_t minor;
+		uint16_t major;
+	} __packed;
+	uint32_t val;
+} pcie_version;
+
+/*
+ * platforms are responsible for providing implementations of these
+ * three functions in a manner which conforms to the Arm PCI Configuration
+ * Space Access Firmware Interface (DEN0115) and the PCIe specification's
+ * sections on PCI configuration access. See the rpi4_pci_svc.c example.
+ */
+uint32_t pci_read_config(uint32_t addr, uint32_t off, uint32_t sz, uint32_t *val);
+uint32_t pci_write_config(uint32_t addr, uint32_t off, uint32_t sz, uint32_t val);
+uint32_t pci_get_bus_for_seg(uint32_t seg, uint32_t *bus_range, uint32_t *nseg);
+
+/* Return codes for Arm PCI Config Space Access Firmware SMC calls */
+#define SMC_PCI_CALL_SUCCESS	       U(0)
+#define SMC_PCI_CALL_NOT_SUPPORTED	-1
+#define SMC_PCI_CALL_INVAL_PARAM	-2
+#define SMC_PCI_CALL_NOT_IMPL		-3
+
+#define SMC_PCI_SZ_8BIT			U(1)
+#define SMC_PCI_SZ_16BIT		U(2)
+#define SMC_PCI_SZ_32BIT		U(4)
+
+#endif /* PCI_SVC_H */

make_helpers/defaults.mk

@@ -212,6 +212,9 @@ SDEI_SUPPORT            	:= 0
 # True Random Number firmware Interface
 TRNG_SUPPORT            	:= 0
 
+# SMCCC PCI support
+SMC_PCI_SUPPORT            	:= 0
+
 # Whether code and read-only data should be put on separate memory pages. The
 # platform Makefile is free to override this value.
 SEPARATE_CODE_AND_RODATA	:= 0