Rename data conversion helpers for PCI config.

Reword some descriptions for better understanding.

devices/common/pci/bandit.cpp

@@ -166,7 +166,7 @@ uint32_t BanditHost::read(uint32_t rgn_start, uint32_t offset, int size)
             details.flags  = PCI_CONFIG_TYPE_0 | PCI_CONFIG_READ;
 
             result = this->dev_map[idsel]->pci_cfg_read(REG_NUM(), details);
-            return pci_cfg_rev_read(result, details);
+            return pci_conv_rd_data(result, details);
         } else {
             LOG_F(
                 ERROR, "%s err: read attempt from non-existing PCI device ??:%02x.%x @%02x",
@@ -225,7 +225,7 @@ void BanditHost::write(uint32_t rgn_start, uint32_t offset, uint32_t value, int
                 this->dev_map[idsel]->pci_cfg_write(REG_NUM(), BYTESWAP_32(value), details);
             } else { // otherwise perform necessary data transformations -> slow path
                 uint32_t old_val = this->dev_map[idsel]->pci_cfg_read(REG_NUM(), details);
-                uint32_t new_val = pci_cfg_rev_write(old_val, value, details);
+                uint32_t new_val = pci_conv_wr_data(old_val, value, details);
                 this->dev_map[idsel]->pci_cfg_write(REG_NUM(), new_val, details);
             }
         } else {

devices/common/pci/pcidevice.h

@@ -116,12 +116,12 @@ protected:
     // PCI configuration space state
     uint16_t    vendor_id;
     uint16_t    device_id;
-    uint32_t    class_rev;       // class code and revision id
+    uint32_t    class_rev;           // class code and revision id
     uint16_t    status = 0;
     uint16_t    command = 0;
-    uint8_t     hdr_type = 0;    // header type
+    uint8_t     hdr_type = 0;        // header type
-    uint8_t     lat_timer = 0;   // latency timer
+    uint8_t     lat_timer = 0;       // latency timer
-    uint8_t     cache_ln_sz = 0; // cache line size
+    uint8_t     cache_ln_sz = 0;     // cache line size
     uint16_t    subsys_id = 0;
     uint16_t    subsys_vndr = 0;
     uint8_t     cap_ptr = 0;

devices/common/pci/pcihost.h

@@ -72,9 +72,14 @@ protected:
     std::vector<PCIDevice*>             io_space_devs;
 };
 
-/* value is dword from PCI config. MSB..LSB of value is stored in PCI config as 0:LSB..3:MSB.
+// Helpers for data conversion in the PCI Configuration space.
-   result is part of value at byte offset from LSB with size bytes (with wrap around) and flipped as required for pci_cfg_read result. */
+
-inline uint32_t pci_cfg_rev_read(uint32_t value, AccessDetails &details) {
+/**
+    Perform size dependent endian swapping for value that is dword from PCI config.
+
+    Unaligned data is handled properly by wrapping around if needed.
+ */
+inline uint32_t pci_conv_rd_data(uint32_t value, AccessDetails &details) {
     switch (details.size << 2 | details.offset) {
     // Bytes
     case 0x04:
@@ -110,10 +115,13 @@ inline uint32_t pci_cfg_rev_read(uint32_t value, AccessDetails &details) {
     }
 }
 
-/* value is dword from PCI config. MSB..LSB of value (3.2.1.0) is stored in PCI config as 0:LSB..3:MSB.
+/**
-   newvalue is flipped bytes (d0.d1.d2.d3, as passed to pci_cfg_write) to be merged into value.
+    Perform size dependent endian swapping for v2, then merge v2 with v1 under
-   result is part of value at byte offset from LSB with size bytes (with wrap around) modified by newvalue. */
+    control of a mask generated according with the size parameter.
-inline uint32_t pci_cfg_rev_write(uint32_t v1, uint32_t v2, AccessDetails &details)
+
+    Unaligned data is handled properly by wrapping around if needed.
+ */
+inline uint32_t pci_conv_wr_data(uint32_t v1, uint32_t v2, AccessDetails &details)
 {
     switch (details.size << 2 | details.offset) {
     // Bytes

devices/memctrl/mpc106.cpp

@@ -136,7 +136,7 @@ uint32_t MPC106::pci_read(uint32_t offset, uint32_t size) {
         details.size   = size;
         details.flags  = PCI_CONFIG_TYPE_0 | PCI_CONFIG_READ;
         uint32_t result = this->dev_map[dev_num]->pci_cfg_read(reg_offs, details);
-        return pci_cfg_rev_read(result, details);
+        return pci_conv_rd_data(result, details);
     } else {
         LOG_F(ERROR, "%s: read attempt from non-existing PCI device ??:%02x.%x @%02x",
             this->name.c_str(), dev_num, fun_num, offset);
@@ -167,7 +167,7 @@ void MPC106::pci_write(uint32_t offset, uint32_t value, uint32_t size) {
             this->dev_map[dev_num]->pci_cfg_write(reg_offs, BYTESWAP_32(value), details);
         } else { // otherwise perform necessary data transformations -> slow path
             uint32_t old_val = this->dev_map[dev_num]->pci_cfg_read(reg_offs, details);
-            uint32_t new_val = pci_cfg_rev_write(old_val, value, details);
+            uint32_t new_val = pci_conv_wr_data(old_val, value, details);
             this->dev_map[dev_num]->pci_cfg_write(reg_offs, new_val, details);
         }
     } else {