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authorDaniel Vetter <daniel.vetter@ffwll.ch>2014-07-07 10:17:56 +0200
committerDaniel Vetter <daniel.vetter@ffwll.ch>2014-07-07 10:17:56 +0200
commitf1615bbe9be4def59c3b3eaddb60722efeed16c2 (patch)
treeca3020e65447576fc1826e819651e6ba072030b5 /drivers/tty/serial/earlycon-arm-semihost.c
parentcfb3c0ab0903abb6ea5215b37eebd9c2a1f057eb (diff)
parentcd3de83f147601356395b57a8673e9c5ff1e59d1 (diff)
Merge tag 'v3.16-rc4' into drm-intel-next-queued
Due to Dave's vacation drm-next hasn't opened yet for 3.17 so I couldn't move my drm-intel-next queue forward yet like I usually do. Just pull in the latest upstream -rc to unblock patch merging - I don't want to needlessly rebase my current patch pile really and void all the testing we've done already. Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/tty/serial/earlycon-arm-semihost.c')
-rw-r--r--drivers/tty/serial/earlycon-arm-semihost.c61
1 files changed, 61 insertions, 0 deletions
diff --git a/drivers/tty/serial/earlycon-arm-semihost.c b/drivers/tty/serial/earlycon-arm-semihost.c
new file mode 100644
index 00000000000..383db10fbb4
--- /dev/null
+++ b/drivers/tty/serial/earlycon-arm-semihost.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * Adapted for ARM and earlycon:
+ * Copyright (C) 2014 Linaro Ltd.
+ * Author: Rob Herring <robh@kernel.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License 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, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/kernel.h>
+#include <linux/console.h>
+#include <linux/init.h>
+#include <linux/serial_core.h>
+
+#ifdef CONFIG_THUMB2_KERNEL
+#define SEMIHOST_SWI "0xab"
+#else
+#define SEMIHOST_SWI "0x123456"
+#endif
+
+/*
+ * Semihosting-based debug console
+ */
+static void smh_putc(struct uart_port *port, int c)
+{
+#ifdef CONFIG_ARM64
+ asm volatile("mov x1, %0\n"
+ "mov x0, #3\n"
+ "hlt 0xf000\n"
+ : : "r" (&c) : "x0", "x1", "memory");
+#else
+ asm volatile("mov r1, %0\n"
+ "mov r0, #3\n"
+ "svc " SEMIHOST_SWI "\n"
+ : : "r" (&c) : "r0", "r1", "memory");
+#endif
+}
+
+static void smh_write(struct console *con, const char *s, unsigned n)
+{
+ struct earlycon_device *dev = con->data;
+ uart_console_write(&dev->port, s, n, smh_putc);
+}
+
+int __init early_smh_setup(struct earlycon_device *device, const char *opt)
+{
+ device->con->write = smh_write;
+ return 0;
+}
+EARLYCON_DECLARE(smh, early_smh_setup);