From fd033712490e4b9f85c68ebd4d79b6a0da66a3fa Mon Sep 17 00:00:00 2001
From: Baptiste Wicht <baptiste.wicht@gmail.com>
Date: Sat, 23 Jul 2016 17:48:02 +0200
Subject: [PATCH] Better PCI support

---
 kernel/include/pci.hpp |  5 +++++
 kernel/src/pci.cpp     | 30 +++++++++++++++++++++++++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/kernel/include/pci.hpp b/kernel/include/pci.hpp
index 767be526..bcf596bf 100644
--- a/kernel/include/pci.hpp
+++ b/kernel/include/pci.hpp
@@ -51,7 +51,12 @@ void detect_devices();
 size_t number_of_devices();
 device_descriptor& device(size_t index);
 
+uint8_t  read_config_byte(uint8_t bus, uint8_t device, uint8_t function, uint8_t offset);
+uint16_t read_config_word(uint8_t bus, uint8_t device, uint8_t function, uint8_t offset);
 uint32_t read_config_dword(uint8_t bus, uint8_t device, uint8_t function, uint8_t offset);
+
+void write_config_byte(uint8_t bus, uint8_t device, uint8_t function, uint8_t offset, uint8_t value);
+void write_config_word(uint8_t bus, uint8_t device, uint8_t function, uint8_t offset, uint16_t value);
 void write_config_dword(uint8_t bus, uint8_t device, uint8_t function, uint8_t offset, uint32_t value);
 
 } //end of namespace pci
diff --git a/kernel/src/pci.cpp b/kernel/src/pci.cpp
index 4718052a..1299664a 100644
--- a/kernel/src/pci.cpp
+++ b/kernel/src/pci.cpp
@@ -127,7 +127,17 @@ pci::device_descriptor& pci::device(size_t index){
     return devices[index];
 }
 
-uint32_t pci::read_config_dword (uint8_t bus, uint8_t device, uint8_t function, uint8_t offset){
+uint8_t pci::read_config_byte(uint8_t bus, uint8_t device, uint8_t function, uint8_t offset){
+    auto value = read_config_dword(bus, device, function, offset);
+    return (value >> ((offset & 3) * 8)) & 0xff;
+}
+
+uint16_t pci::read_config_word(uint8_t bus, uint8_t device, uint8_t function, uint8_t offset){
+    auto value = read_config_dword(bus, device, function, offset);
+    return (value >> ((offset & 3) * 8)) & 0xffff;
+}
+
+uint32_t pci::read_config_dword(uint8_t bus, uint8_t device, uint8_t function, uint8_t offset){
     uint32_t address =
         static_cast<uint32_t>(1 << 31)  //enabled
         | (uint32_t(bus) << 16)  //bus number
@@ -140,6 +150,24 @@ uint32_t pci::read_config_dword (uint8_t bus, uint8_t device, uint8_t function,
     return in_dword(PCI_CONFIG_DATA);
 }
 
+void pci::write_config_byte(uint8_t bus, uint8_t device, uint8_t function, uint8_t offset, uint8_t value){
+    auto tmp = read_config_dword(bus, device, function, offset);
+
+    tmp &= ~(0xff << ((offset & 3) * 8));
+    tmp |= (value << ((offset & 3) * 8));
+
+    write_config_dword(bus, device, function, offset, tmp);
+}
+
+void pci::write_config_word(uint8_t bus, uint8_t device, uint8_t function, uint8_t offset, uint16_t value){
+    auto tmp = read_config_dword(bus, device, function, offset);
+
+    tmp &= ~(0xffff << ((offset & 3) * 8));
+    tmp |= (value << ((offset & 3) * 8));
+
+    write_config_dword(bus, device, function, offset, tmp);
+}
+
 void pci::write_config_dword (uint8_t bus, uint8_t device, uint8_t function, uint8_t offset, uint32_t value){
     uint32_t address =
         static_cast<uint32_t>(1 << 31)  //enabled