[platform][pc] add a routine to read the cmos memory

platform/pc/cmos.c

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2019 Travis Geiselbrecht
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include <platform/cmos.h>
+
+#include <lk/trace.h>
+#include <lk/debug.h>
+#include <kernel/spinlock.h>
+#include <platform/pc.h>
+
+static spin_lock_t lock = SPIN_LOCK_INITIAL_VALUE;
+
+uint8_t cmos_read(uint8_t reg) {
+    spin_lock_saved_state_t state;
+    spin_lock_irqsave(&lock, state);
+
+    outp(CMOS_CONTROL_REG, reg | 0x80);
+    uint8_t val = inp(CMOS_DATA_REG);
+
+    spin_unlock_irqrestore(&lock, state);
+
+    return val;
+}
+
+

platform/pc/include/platform/cmos.h

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2019 Travis Geiselbrecht
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#pragma once
+
+#include <stdint.h>
+
+/* cmos map for PC */
+#define CMOS_REG_FLOPPY (0x10)
+
+uint8_t cmos_read(uint8_t reg);

platform/pc/include/platform/pc/iomap.h

@@ -16,6 +16,10 @@
 #define I8042_STATUS_REG    0x64
 #define I8042_DATA_REG      0x60
 
+/* CMOS/RTC registers */
+#define CMOS_CONTROL_REG    0x70
+#define CMOS_DATA_REG       0x71
+
 /* CGA registers */
 #define CGA_INDEX_REG       0x3d4
 #define CGA_DATA_REG        0x3d5

platform/pc/rules.mk

@@ -17,6 +17,7 @@ MODULE_DEPS += dev/net/e1000
 endif
 
 MODULE_SRCS += \
+    $(LOCAL_DIR)/cmos.c \
     $(LOCAL_DIR)/console.c \
     $(LOCAL_DIR)/debug.c \
     $(LOCAL_DIR)/ide.c \

platform/pc/timer.c

@@ -147,7 +147,6 @@ static void platform_halt_timers(void) {
 
 status_t platform_set_oneshot_timer(platform_timer_callback callback,
                                     void *arg, lk_time_t interval) {
-
     uint32_t count;
 
     spin_lock_saved_state_t state;