acpi: /dev/acpi

kernel-src/arch/x86-64/main.c

@@ -80,6 +80,8 @@ void kernel_entry() {
 	sockfs_init();
 	ext2_init();
 
+	acpi_initdevice();
+
 	tty_init();
 	pty_init();
 

kernel-src/include/kernel/acpi.h

@@ -10,4 +10,9 @@ void acpi_init(void);
 int acpi_poweroff(void);
 int acpi_reboot(void);
 
+void acpi_signaldevice(char c);
+
+// Depends on devfs
+void acpi_initdevice(void);
+
 #endif

kernel-src/include/kernel/devfs.h

@@ -18,6 +18,7 @@
 #define DEV_MAJOR_NET 10
 #define DEV_MAJOR_MOUSE 11
 #define DEV_MAJOR_PTY 12
+#define DEV_MAJOR_ACPI 13
 
 typedef struct {
 	int (*open)(int minor, vnode_t **vnode, int flags);

kernel-src/io/acpi/acpi.c

@@ -22,7 +22,7 @@ void acpi_early_init(void) {
 
 void acpi_dopoweroff(uacpi_handle ctx) {
 	(void)ctx;
-	acpi_poweroff();
+	acpi_signaldevice('p');
 }
 
 static uacpi_interrupt_ret handle_pwrbtn(uacpi_handle ctx) {

kernel-src/io/acpi/dev.c

@@ -0,0 +1,119 @@
+#include <kernel/acpi.h>
+#include <kernel/devfs.h>
+#include <kernel/poll.h>
+#include <spinlock.h>
+#include <ringbuffer.h>
+#include <logging.h>
+
+static ringbuffer_t ringbuffer;
+static pollheader_t pollheader;
+static spinlock_t lock;
+
+void acpi_signaldevice(char c) {
+	long ipl = spinlock_acquireraiseipl(&lock, IPL_DPC);
+
+	if (ringbuffer_write(&ringbuffer, &c, 1))
+		poll_event(&pollheader, POLLIN);
+
+	spinlock_releaseloweripl(&lock, ipl);
+}
+
+static int internalpoll(polldata_t *data, int events) {
+	int revents = 0;
+	if (events & POLLOUT)
+		revents |= POLLOUT;
+
+	if ((events & POLLIN) && RINGBUFFER_DATACOUNT(&ringbuffer))
+		revents |= POLLIN;
+
+	if (revents == 0)
+		poll_add(&pollheader, data, events);
+
+	return revents;
+}
+
+static int read(int minor, void *buffer, size_t size, uintmax_t offset, int flags, size_t *readc) {
+	*readc = 0;
+
+	if (size < 1)
+		return 0;
+
+	polldesc_t desc;
+	int error = poll_initdesc(&desc, 1);
+	if (error)
+		return error;
+
+	for (;;) {
+		long ipl = spinlock_acquireraiseipl(&lock, IPL_DPC);
+
+		int revents = internalpoll(&desc.data[0], POLLIN);
+
+		spinlock_releaseloweripl(&lock, ipl);
+
+		if (revents)
+			break;
+
+		if (flags & V_FFLAGS_NONBLOCKING) {
+			error = EAGAIN;
+			goto leave;
+		}
+
+		error = poll_dowait(&desc, 0);
+
+		if (error)
+			goto leave;
+
+		poll_leave(&desc);
+	}
+
+	long ipl = spinlock_acquireraiseipl(&lock, IPL_DPC);
+
+	*readc = ringbuffer_read(&ringbuffer, buffer, size);
+
+	spinlock_releaseloweripl(&lock, ipl);
+
+	leave:
+	poll_leave(&desc);
+	poll_destroydesc(&desc);
+	return error;
+}
+
+static int write(int minor, void *buffer, size_t size, uintmax_t offset, int flags, size_t *writec) {
+	if (size < 1) {
+		*writec = 0;
+		return 0;
+	}
+
+	char *c = buffer;
+	switch (*c) {
+		case 'p':
+			acpi_poweroff();
+			break;
+		case 'r':
+			acpi_reboot();
+			break;
+	}
+
+	return EIO;
+}
+
+static int poll(int minor, polldata_t *data, int events) {
+	long ipl = spinlock_acquireraiseipl(&lock, IPL_DPC);
+
+	int revents = internalpoll(data, events);
+
+	spinlock_releaseloweripl(&lock, ipl);
+	return revents;
+}
+
+static devops_t acpiops = {
+	.read = read,
+	.write = write,
+	.poll = poll
+};
+
+void acpi_initdevice(void) {
+	__assert(devfs_register(&acpiops, "acpi", V_TYPE_CHDEV, DEV_MAJOR_ACPI, 0, 0600, NULL) == 0);
+	__assert(ringbuffer_init(&ringbuffer, 64) == 0);
+	POLL_INITHEADER(&pollheader);
+}