tilegx: provide kernel support for the tilegx UART shim

The TILE-Gx chip includes an on-chip UART.  This change adds support
for using the UART from within the kernel.  The UART shim has more
functionality than is exposed here, but to keep the kernel code and
binary simpler, this is a subset of the full API designed to enable
a standard Linux tty serial driver only.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

1 files changed, 87 insertions, 0 deletions

diff --git a/arch/tile/gxio/uart.c b/arch/tile/gxio/uart.c
new file mode 100644
index 0000000..ba58517
--- /dev/null
+++ b/arch/tile/gxio/uart.c
@@ -0,0 +1,87 @@
+/*
+ * Copyright 2013 Tilera Corporation. 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
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   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, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ */
+
+/*
+ * Implementation of UART gxio calls.
+ */
+
+#include <linux/io.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+
+#include <gxio/uart.h>
+#include <gxio/iorpc_globals.h>
+#include <gxio/iorpc_uart.h>
+#include <gxio/kiorpc.h>
+
+int gxio_uart_init(gxio_uart_context_t *context, int uart_index)
+{
+	char file[32];
+	int fd;
+
+	snprintf(file, sizeof(file), "uart/%d/iorpc", uart_index);
+	fd = hv_dev_open((HV_VirtAddr) file, 0);
+	if (fd < 0) {
+		if (fd >= GXIO_ERR_MIN && fd <= GXIO_ERR_MAX)
+			return fd;
+		else
+			return -ENODEV;
+	}
+
+	context->fd = fd;
+
+	/* Map in the MMIO space. */
+	context->mmio_base = (void __force *)
+		iorpc_ioremap(fd, HV_UART_MMIO_OFFSET, HV_UART_MMIO_SIZE);
+
+	if (context->mmio_base == NULL) {
+		hv_dev_close(context->fd);
+		context->fd = -1;
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(gxio_uart_init);
+
+int gxio_uart_destroy(gxio_uart_context_t *context)
+{
+	iounmap((void __force __iomem *)(context->mmio_base));
+	hv_dev_close(context->fd);
+
+	context->mmio_base = NULL;
+	context->fd = -1;
+
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(gxio_uart_destroy);
+
+/* UART register write wrapper. */
+void gxio_uart_write(gxio_uart_context_t *context, uint64_t offset,
+		     uint64_t word)
+{
+	__gxio_mmio_write(context->mmio_base + offset, word);
+}
+
+EXPORT_SYMBOL_GPL(gxio_uart_write);
+
+/* UART register read wrapper. */
+uint64_t gxio_uart_read(gxio_uart_context_t *context, uint64_t offset)
+{
+	return __gxio_mmio_read(context->mmio_base + offset);
+}
+
+EXPORT_SYMBOL_GPL(gxio_uart_read);