Merge changes from topic "Arm_PCI_Config_Space_Interface" into integration

* changes:
  TF-A: Document SMC_PCI_SUPPORT option
  SMCCC/PCI: Handle std svc boilerplate
  SMCCC/PCI: Add initial PCI conduit definitions
  SMCCC: Hoist SMC_32 sanitization

bl31/bl31.mk

@@ -95,6 +95,10 @@ BL31_SOURCES		+=	lib/cpus/aarch64/wa_cve_2017_5715_bpiall.S	\
 				lib/cpus/aarch64/wa_cve_2017_5715_mmu.S
 endif
 
+ifeq ($(SMC_PCI_SUPPORT),1)
+BL31_SOURCES		+=	services/std_svc/pci_svc.c
+endif
+
 BL31_LINKERFILE		:=	bl31/bl31.ld.S
 
 # Flag used to indicate if Crash reporting via console should be included

docs/getting_started/build-options.rst

@@ -579,6 +579,11 @@ Common build options
    ``BL31_NOBITS_LIMIT``. When the option is ``0`` (the default), NOBITS
    sections are placed in RAM immediately following the loaded firmware image.
 
+-  ``SMC_PCI_SUPPORT``: This option allows platforms to handle PCI configuration
+   access requests via a standard SMCCC defined in `DEN0115`_. When combined with
+   UEFI+ACPI this can provide a certain amount of OS forward compatibility
+   with newer platforms that aren't ECAM compliant.
+
 -  ``SPD``: Choose a Secure Payload Dispatcher component to be built into TF-A.
    This build option is only valid if ``ARCH=aarch64``. The value should be
    the path to the directory containing the SPD source, relative to
@@ -849,3 +854,6 @@ commands can be used:
 --------------
 
 *Copyright (c) 2019-2021, Arm Limited. All rights reserved.*
+
+.. _DEN0115: https://developer.arm.com/docs/den0115/latest
+

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

services/std_svc/pci_svc.c

+/*
+ * Copyright (c) 2021, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <stdint.h>
+
+#include <common/debug.h>
+#include <common/runtime_svc.h>
+#include <services/pci_svc.h>
+#include <services/std_svc.h>
+#include <smccc_helpers.h>
+
+static uint64_t validate_rw_addr_sz(uint32_t addr, uint64_t off, uint64_t sz)
+{
+	uint32_t nseg;
+	uint32_t ret;
+	uint32_t start_end_bus;
+
+	ret = pci_get_bus_for_seg(PCI_ADDR_SEG(addr), &start_end_bus, &nseg);
+
+	if (ret != SMC_PCI_CALL_SUCCESS) {
+		return SMC_PCI_CALL_INVAL_PARAM;
+	}
+	switch (sz) {
+	case SMC_PCI_SZ_8BIT:
+	case SMC_PCI_SZ_16BIT:
+	case SMC_PCI_SZ_32BIT:
+		break;
+	default:
+		return SMC_PCI_CALL_INVAL_PARAM;
+	}
+	if ((off + sz) > (PCI_OFFSET_MASK + 1U)) {
+		return SMC_PCI_CALL_INVAL_PARAM;
+	}
+	return SMC_PCI_CALL_SUCCESS;
+}
+
+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)
+{
+	switch (smc_fid) {
+	case SMC_PCI_VERSION: {
+		pcie_version ver;
+
+		ver.major = 1U;
+		ver.minor = 0U;
+		SMC_RET4(handle, ver.val, 0U, 0U, 0U);
+	}
+	case SMC_PCI_FEATURES:
+		switch (x1) {
+		case SMC_PCI_VERSION:
+		case SMC_PCI_FEATURES:
+		case SMC_PCI_READ:
+		case SMC_PCI_WRITE:
+		case SMC_PCI_SEG_INFO:
+			SMC_RET1(handle, SMC_PCI_CALL_SUCCESS);
+		default:
+			SMC_RET1(handle, SMC_PCI_CALL_NOT_SUPPORTED);
+		}
+		break;
+	case SMC_PCI_READ: {
+		uint32_t ret;
+
+		if (validate_rw_addr_sz(x1, x2, x3) != SMC_PCI_CALL_SUCCESS) {
+			SMC_RET2(handle, SMC_PCI_CALL_INVAL_PARAM, 0U);
+		}
+		if (x4 != 0U) {
+			SMC_RET2(handle, SMC_PCI_CALL_INVAL_PARAM, 0U);
+		}
+		if (pci_read_config(x1, x2, x3, &ret) != 0U) {
+			SMC_RET2(handle, SMC_PCI_CALL_INVAL_PARAM, 0U);
+		} else {
+			SMC_RET2(handle, SMC_PCI_CALL_SUCCESS, ret);
+		}
+		break;
+	}
+	case SMC_PCI_WRITE: {
+		uint32_t ret;
+
+		if (validate_rw_addr_sz(x1, x2, x3) != SMC_PCI_CALL_SUCCESS) {
+			SMC_RET1(handle, SMC_PCI_CALL_INVAL_PARAM);
+		}
+		ret = pci_write_config(x1, x2, x3, x4);
+		SMC_RET1(handle, ret);
+		break;
+	}
+	case SMC_PCI_SEG_INFO: {
+		uint32_t nseg;
+		uint32_t ret;
+		uint32_t start_end_bus;
+
+		if ((x2 != 0U) || (x3 != 0U) || (x4 != 0U)) {
+		    SMC_RET3(handle, SMC_PCI_CALL_INVAL_PARAM, 0U, 0U);
+		}
+		ret = pci_get_bus_for_seg(x1, &start_end_bus, &nseg);
+		SMC_RET3(handle, ret, start_end_bus, nseg);
+		break;
+	}
+	default:
+		/* should be unreachable */
+		WARN("Unimplemented PCI Service Call: 0x%x\n", smc_fid);
+		SMC_RET1(handle, SMC_PCI_CALL_NOT_SUPPORTED);
+	}
+}

services/std_svc/std_svc_setup.c

@@ -13,6 +13,7 @@
 #include <lib/pmf/pmf.h>
 #include <lib/psci/psci.h>
 #include <lib/runtime_instr.h>
+#include <services/pci_svc.h>
 #include <services/sdei.h>
 #include <services/spm_mm_svc.h>
 #include <services/spmd_svc.h>
@@ -82,6 +83,15 @@ static uintptr_t std_svc_smc_handler(uint32_t smc_fid,
 			     void *handle,
 			     u_register_t flags)
 {
+	if (((smc_fid >> FUNCID_CC_SHIFT) & FUNCID_CC_MASK) == SMC_32) {
+		/* 32-bit SMC function, clear top parameter bits */
+
+		x1 &= UINT32_MAX;
+		x2 &= UINT32_MAX;
+		x3 &= UINT32_MAX;
+		x4 &= UINT32_MAX;
+	}
+
 	/*
 	 * Dispatch PSCI calls to PSCI SMC handler and return its return
 	 * value
@@ -149,6 +159,13 @@ static uintptr_t std_svc_smc_handler(uint32_t smc_fid,
 	}
 #endif
 
+#if SMC_PCI_SUPPORT
+	if (is_pci_fid(smc_fid)) {
+		return pci_smc_handler(smc_fid, x1, x2, x3, x4, cookie, handle,
+				       flags);
+	}
+#endif
+
 	switch (smc_fid) {
 	case ARM_STD_SVC_CALL_COUNT:
 		/*