1 files changed, 133 insertions, 0 deletions

diff --git a/drivers/tty/hvc/hvc_dcc.c b/drivers/tty/hvc/hvc_dcc.c
new file mode 100644
index 000000000000..6470f63deb4b
--- /dev/null
+++ b/drivers/tty/hvc/hvc_dcc.c
@@ -0,0 +1,133 @@
+/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+
+#include <asm/processor.h>
+
+#include "hvc_console.h"
+
+/* DCC Status Bits */
+#define DCC_STATUS_RX           (1 << 30)
+#define DCC_STATUS_TX           (1 << 29)
+
+static inline u32 __dcc_getstatus(void)
+{
+        u32 __ret;
+
+        asm("mrc p14, 0, %0, c0, c1, 0  @ read comms ctrl reg"
+                : "=r" (__ret) : : "cc");
+
+        return __ret;
+}
+
+
+#if defined(CONFIG_CPU_V7)
+static inline char __dcc_getchar(void)
+{
+        char __c;
+
+        asm("get_wait:  mrc p14, 0, pc, c0, c1, 0                          \n\
+                        bne get_wait                                       \n\
+                        mrc p14, 0, %0, c0, c5, 0       @ read comms data reg"
+                : "=r" (__c) : : "cc");
+
+        return __c;
+}
+#else
+static inline char __dcc_getchar(void)
+{
+        char __c;
+
+        asm("mrc p14, 0, %0, c0, c5, 0  @ read comms data reg"
+                : "=r" (__c));
+
+        return __c;
+}
+#endif
+
+#if defined(CONFIG_CPU_V7)
+static inline void __dcc_putchar(char c)
+{
+        asm("put_wait:  mrc p14, 0, pc, c0, c1, 0                 \n\
+                        bcs put_wait                              \n\
+                        mcr p14, 0, %0, c0, c5, 0                   "
+        : : "r" (c) : "cc");
+}
+#else
+static inline void __dcc_putchar(char c)
+{
+        asm("mcr p14, 0, %0, c0, c5, 0  @ write a char"
+                : /* no output register */
+                : "r" (c));
+}
+#endif
+
+static int hvc_dcc_put_chars(uint32_t vt, const char *buf, int count)
+{
+        int i;
+
+        for (i = 0; i < count; i++) {
+                while (__dcc_getstatus() & DCC_STATUS_TX)
+                        cpu_relax();
+
+                __dcc_putchar((char)(buf[i] & 0xFF));
+        }
+
+        return count;
+}
+
+static int hvc_dcc_get_chars(uint32_t vt, char *buf, int count)
+{
+        int i;
+
+        for (i = 0; i < count; ++i) {
+                int c = -1;
+
+                if (__dcc_getstatus() & DCC_STATUS_RX)
+                        c = __dcc_getchar();
+                if (c < 0)
+                        break;
+                buf[i] = c;
+        }
+
+        return i;
+}
+
+static const struct hv_ops hvc_dcc_get_put_ops = {
+        .get_chars = hvc_dcc_get_chars,
+        .put_chars = hvc_dcc_put_chars,
+};
+
+static int __init hvc_dcc_console_init(void)
+{
+        hvc_instantiate(0, 0, &hvc_dcc_get_put_ops);
+        return 0;
+}
+console_initcall(hvc_dcc_console_init);
+
+static int __init hvc_dcc_init(void)
+{
+        hvc_alloc(0, 0, &hvc_dcc_get_put_ops, 128);
+        return 0;
+}
+device_initcall(hvc_dcc_init);