pci: add pci config space read/write helpers

Add legacy (IO ports based) access mechanism to PCI configuration space.
The helpers allow to read/write 8-bit, 16-bit and 32-bit values.
Separate helper pci_cfg_set_addr() is used for address selection.

Signed-off-by: Pawel Wieczorkiewicz <wipawel@amazon.de>

Author: wipawel

include/arch/x86/pci_cfg.h

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+/*
+ * Copyright © 2021 Amazon.com, Inc. or its affiliates.
+ * All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifndef KTF_PCI_CFG_H
+#define KTF_PCI_CFG_H
+
+#include <ktf.h>
+#include <lib.h>
+
+#define PCI_IO_PORT_ADDRESS 0xcf8
+#define PCI_IO_PORT_DATA    0xcfc
+
+union pci_cfg_addr {
+    struct {
+        uint32_t zero : 2, reg : 6, fn : 3, dev : 5, bus : 8, rsvd : 7, ecsm : 1;
+    } __packed;
+    uint32_t val;
+};
+typedef union pci_cfg_addr pci_cfg_addr_t;
+
+union pci_cfg_value {
+    uint8_t byte[4];
+    uint16_t word[2];
+    uint16_t dword;
+};
+typedef union pci_cfg_value pci_cfg_value_t;
+
+/* Static declarations */
+
+static inline void pci_cfg_set_addr(uint8_t bus, uint8_t dev, uint8_t func, uint8_t reg) {
+    pci_cfg_addr_t addr;
+
+    addr.val = 0;
+    addr.reg = reg;
+    addr.fn = func;
+    addr.dev = dev;
+    addr.bus = bus;
+
+    outd(PCI_IO_PORT_ADDRESS, addr.val);
+}
+
+static inline uint8_t pci_cfg_read8(uint8_t bus, uint8_t dev, uint8_t func, uint8_t reg) {
+    pci_cfg_set_addr(bus, dev, func, reg);
+    return inb(PCI_IO_PORT_DATA);
+}
+
+static inline void pci_cfg_write8(uint8_t bus, uint8_t dev, uint8_t func, uint8_t reg,
+                                  uint8_t value) {
+    pci_cfg_set_addr(bus, dev, func, reg);
+    outb(PCI_IO_PORT_DATA, value);
+}
+
+static inline uint16_t pci_cfg_read16(uint8_t bus, uint8_t dev, uint8_t func,
+                                      uint8_t reg) {
+    pci_cfg_set_addr(bus, dev, func, reg);
+    return inw(PCI_IO_PORT_DATA);
+}
+
+static inline void pci_cfg_write16(uint8_t bus, uint8_t dev, uint8_t func, uint8_t reg,
+                                   uint16_t value) {
+    pci_cfg_set_addr(bus, dev, func, reg);
+    outw(PCI_IO_PORT_DATA, value);
+}
+
+static inline uint32_t pci_cfg_read(uint8_t bus, uint8_t dev, uint8_t func, uint8_t reg) {
+    pci_cfg_set_addr(bus, dev, func, reg);
+    return ind(PCI_IO_PORT_DATA);
+}
+
+static inline void pci_cfg_write(uint8_t bus, uint8_t dev, uint8_t func, uint8_t reg,
+                                 uint32_t value) {
+    pci_cfg_set_addr(bus, dev, func, reg);
+    outd(PCI_IO_PORT_DATA, value);
+}
+
+/* External declarations */
+
+#endif /* KTF_PCI_CFG_H */