hvc: add Blackfin JTAG console support

This converts the existing bfin_jtag_comm TTY driver to the HVC layer so
that the common HVC code can worry about all of the TTY/polling crap and
leave the Blackfin code to worry about the Blackfin bits.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 115 insertions, 0 deletions

diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index b7980a83ce2d..17f9b968b988 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -691,6 +691,15 @@ config HVC_DCC
          driver. This console is used through a JTAG only on ARM. If you don't have
          a JTAG then you probably don't want this option.
 
+config HVC_BFIN_JTAG
+        bool "Blackfin JTAG console"
+        depends on BLACKFIN
+        select HVC_DRIVER
+        help
+         This console uses the Blackfin JTAG to create a console under the
+         the HVC driver.  If you don't have JTAG, then you probably don't
+         want this option.
+
 config VIRTIO_CONSOLE
         tristate "Virtio console"
         depends on VIRTIO
diff --git a/drivers/tty/hvc/Makefile b/drivers/tty/hvc/Makefile
index e6bed5f177ff..7b0edbce9009 100644
--- a/drivers/tty/hvc/Makefile
+++ b/drivers/tty/hvc/Makefile
@@ -9,5 +9,6 @@ obj-$(CONFIG_HVC_IRQ)		+= hvc_irq.o
 obj-$(CONFIG_HVC_XEN)           += hvc_xen.o
 obj-$(CONFIG_HVC_IUCV)          += hvc_iucv.o
 obj-$(CONFIG_HVC_UDBG)          += hvc_udbg.o
+obj-$(CONFIG_HVC_BFIN_JTAG)     += hvc_bfin_jtag.o
 obj-$(CONFIG_HVCS)              += hvcs.o
 obj-$(CONFIG_VIRTIO_CONSOLE)    += virtio_console.o
diff --git a/drivers/tty/hvc/hvc_bfin_jtag.c b/drivers/tty/hvc/hvc_bfin_jtag.c
new file mode 100644
index 000000000000..31d6cc6a77af
--- /dev/null
+++ b/drivers/tty/hvc/hvc_bfin_jtag.c
@@ -0,0 +1,105 @@
+/*
+ * Console via Blackfin JTAG Communication
+ *
+ * Copyright 2008-2011 Analog Devices Inc.
+ *
+ * Enter bugs at http://blackfin.uclinux.org/
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#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 "hvc_console.h"
+
+/* See the Debug/Emulation chapter in the HRM */
+#define EMUDOF   0x00000001     /* EMUDAT_OUT full & valid */
+#define EMUDIF   0x00000002     /* EMUDAT_IN full & valid */
+#define EMUDOOVF 0x00000004     /* EMUDAT_OUT overflow */
+#define EMUDIOVF 0x00000008     /* EMUDAT_IN overflow */
+
+/* Helper functions to glue the register API to simple C operations */
+static inline uint32_t bfin_write_emudat(uint32_t emudat)
+{
+        __asm__ __volatile__("emudat = %0;" : : "d"(emudat));
+        return emudat;
+}
+
+static inline uint32_t bfin_read_emudat(void)
+{
+        uint32_t emudat;
+        __asm__ __volatile__("%0 = emudat;" : "=d"(emudat));
+        return emudat;
+}
+
+/* Send data to the host */
+static int hvc_bfin_put_chars(uint32_t vt, const char *buf, int count)
+{
+        static uint32_t outbound_len;
+        uint32_t emudat;
+        int ret;
+
+        if (bfin_read_DBGSTAT() & EMUDOF)
+                return 0;
+
+        if (!outbound_len) {
+                outbound_len = count;
+                bfin_write_emudat(outbound_len);
+                return 0;
+        }
+
+        ret = min(outbound_len, (uint32_t)4);
+        memcpy(&emudat, buf, ret);
+        bfin_write_emudat(emudat);
+        outbound_len -= ret;
+
+        return ret;
+}
+
+/* Receive data from the host */
+static int hvc_bfin_get_chars(uint32_t vt, char *buf, int count)
+{
+        static uint32_t inbound_len;
+        uint32_t emudat;
+        int ret;
+
+        if (!(bfin_read_DBGSTAT() & EMUDIF))
+                return 0;
+        emudat = bfin_read_emudat();
+
+        if (!inbound_len) {
+                inbound_len = emudat;
+                return 0;
+        }
+
+        ret = min(inbound_len, (uint32_t)4);
+        memcpy(buf, &emudat, ret);
+        inbound_len -= ret;
+
+        return ret;
+}
+
+/* Glue the HVC layers to the Blackfin layers */
+static const struct hv_ops hvc_bfin_get_put_ops = {
+        .get_chars = hvc_bfin_get_chars,
+        .put_chars = hvc_bfin_put_chars,
+};
+
+static int __init hvc_bfin_console_init(void)
+{
+        hvc_instantiate(0, 0, &hvc_bfin_get_put_ops);
+        return 0;
+}
+console_initcall(hvc_bfin_console_init);
+
+static int __init hvc_bfin_init(void)
+{
+        hvc_alloc(0, 0, &hvc_bfin_get_put_ops, 128);
+        return 0;
+}
+device_initcall(hvc_bfin_init);