Add a way to handle hardware quirks at init or later in the code. Add ASUS TUSL2-C ASB100 Mux as (working) example (#77)

app/main.c

@@ -22,6 +22,7 @@
 #include "cpuid.h"
 #include "cpuinfo.h"
 #include "hwctrl.h"
+#include "hwquirks.h"
 #include "io.h"
 #include "keyboard.h"
 #include "pmem.h"
@@ -219,6 +220,8 @@ static void global_init(void)
 
     smbios_init();
 
+    quirks_init();
+
     badram_init();
 
     config_init();

build32/Makefile

@@ -20,6 +20,7 @@ SYS_OBJS = system/cpuid.o \
            system/ehci.o \
            system/font.o \
            system/hwctrl.o \
+           system/hwquirks.o \
            system/keyboard.o \
            system/ohci.o \
            system/pci.o \

build64/Makefile

@@ -20,6 +20,7 @@ SYS_OBJS = system/cpuid.o \
            system/ehci.o \
            system/font.o \
            system/hwctrl.o \
+           system/hwquirks.o \
            system/keyboard.o \
            system/ohci.o \
            system/pci.o \

system/hwquirks.c

@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2004-2022 Samuel Demeulemeester
+//
+// ------------------------
+// This file is used to detect quirks on specific hardware
+// that require proprietary init here *OR* different code path
+// later in various part of the code.
+//
+// Please add a quick comment for every quirk added to the list.
+
+#include "hwquirks.h"
+#include "io.h"
+#include "pci.h"
+#include "unistd.h"
+
+quirk_t quirk;
+
+// --------------------------------------
+// -- Private quirk-specific functions --
+// --------------------------------------
+
+static void asus_tusl2_configure_mux(void)
+{
+    uint8_t muxreg;
+
+    // Enter ASB100 Config Mode
+    outb(0x87, 0x2E);
+    outb(0x87, 0x2E);
+    usleep(200);
+
+    // Write LPC Command to access Config Mode Reg
+    lpc_outb(0x7, 0x8);
+
+    // Read Config Mode Register
+    muxreg = lpc_inb(0xF1);
+
+    // Change Smbus Mux Channel & Write Config Mode Register
+    muxreg &= 0xE7;
+    muxreg |= 0x10;
+    lpc_outb(0xF1, muxreg);
+    usleep(200);
+
+    // Leave Config Mode
+    outb(0xAA, 0x2E);
+}
+
+// ---------------------
+// -- Public function --
+// ---------------------
+
+void quirks_init(void)
+{
+    quirk.id        = QUIRK_NONE;
+    quirk.type      = QUIRK_TYPE_NONE;
+    quirk.root_vid  = pci_config_read16(0, 0, 0, 0);
+    quirk.root_did  = pci_config_read16(0, 0, 0, 2);
+
+    //  ------------------------
+    //  -- ASUS TUSL2-C Quirk --
+    //  ------------------------
+    // This motherboard has an ASB100 ASIC with a SMBUS Mux Integrated.
+    // To access SPD later in the code, we need to configure the mux.
+    // PS: Detection via DMI is unreliable, so using Root PCI Registers
+    if (quirk.root_vid == 0x8086 && quirk.root_did == 0x1130) {     // Intel i815
+        if (pci_config_read16(0, 0, 0, 0x2C) == 0x1043) {           // ASUS
+            if (pci_config_read16(0, 0, 0, 0x2E) == 0x8027) {       // TUSL2-C
+                quirk.id    = QUIRK_TUSL2;
+                quirk.type |= QUIRK_TYPE_SMBUS;
+                asus_tusl2_configure_mux();
+            }
+        }
+    }
+}

system/hwquirks.h

@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2004-2022 Sam Demeulemeester
+#ifndef _QUIRK_H_
+#define _QUIRK_H_
+/**
+ *
+ * Provides support for hardware quirks
+ *
+ */
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#define QUIRK_TYPE_NONE     0b00000000
+#define QUIRK_TYPE_USB      0b00000001
+#define QUIRK_TYPE_SMP      0b00000010
+#define QUIRK_TYPE_SMBIOS   0b00000100
+#define QUIRK_TYPE_SMBUS    0b00001000
+#define QUIRK_TYPE_TIMER    0b00010000
+
+typedef enum {
+    QUIRK_NONE,
+    QUIRK_TUSL2
+} quirk_id_t;
+
+typedef struct {
+    quirk_id_t   id;
+    uint8_t      type;
+    uint16_t     root_vid;
+    uint16_t     root_did;
+} quirk_t;
+
+extern quirk_t quirk;
+
+void quirks_init(void);
+
+#endif /* _QUIRK_H_ */

system/pci.c

@@ -244,6 +244,30 @@ void pci_config_write32(int bus, int dev, int func, int reg, uint32_t value)
     }
 }
 
+
+// -------------
+// LPC Functions
+// -------------
+
+void lpc_outb(uint8_t cmd, uint8_t data)
+{
+    outb(cmd, 0x2E);
+    usleep(100);
+    outb(data, 0x2F);
+    usleep(100);
+}
+
+uint8_t lpc_inb(uint8_t reg)
+{
+    outb(reg, 0x2E);
+    usleep(100);
+    return inb(0x2F);
+}
+
+// ---------------------------------------
+// AMD System Management Network Functions
+// ---------------------------------------
+
 uint32_t amd_smn_read(uint32_t adr)
 {
   pci_config_write32(0, 0, 0, 0x60, adr);

system/pci.h

@@ -60,6 +60,13 @@ void pci_config_write16(int bus, int dev, int func, int reg, uint16_t value);
 void pci_config_write32(int bus, int dev, int func, int reg, uint32_t value);
 
 
+/**
+ * Basic LPC Functions
+ */
+
+void lpc_outb(uint8_t cmd, uint8_t data);
+uint8_t lpc_inb(uint8_t reg);
+
 /*
  * Add some SNM related function (S.DEMEULEMEESTER)
  */