riscv: add the lowrisc/nexys4ddr mainboard

This was tested at the coreboot meeting in Berlin.

The uart programming may still not be right but when used with
the lowrisc bitstream for the board we were able to load
and start linux, although it does not yet get far due to
PTE version issues with lowrisc.

Change-Id: Ia1de1a92762631c9d7bb3d41b04f95296144caa3
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-on: https://review.coreboot.org/17132
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)

1 files changed, 103 insertions, 0 deletions

diff --git a/src/mainboard/lowrisc/nexys4ddr/util.c b/src/mainboard/lowrisc/nexys4ddr/util.c
new file mode 100644
index 0000000000..32cdb6d573
--- /dev/null
+++ b/src/mainboard/lowrisc/nexys4ddr/util.c
@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2013, The Regents of the University of California (Regents).
+ * All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the Regents nor the
+ * names of its contributors may be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * IN NO EVENT SHALL REGENTS BE LIABLE TO ANY PARTY FOR DIRECT,
+ * INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
+ * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
+ * DOCUMENTATION, EVEN IF REGENTS HAS BEEN ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * REGENTS SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE. THE SOFTWARE AND ACCOMPANYING
+ * DOCUMENTATION, IF ANY, PROVIDED HEREUNDER IS PROVIDED "AS
+ * IS". REGENTS HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT,
+ * UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ */
+
+#include <arch/barrier.h>
+#include <arch/errno.h>
+#include <atomic.h>
+#include <console/console.h>
+#include <spike_util.h>
+#include <string.h>
+#include <vm.h>
+
+uintptr_t mcall_query_memory(uintptr_t id, memory_block_info *info)
+{
+	if (id == 0) {
+		mprv_write_ulong(&info->base, 2U*GiB);
+
+		/* TODO: Return the correct value */
+		mprv_write_ulong(&info->size, 1*GiB);
+		return 0;
+	}
+
+	return -1;
+}
+
+uintptr_t mcall_send_ipi(uintptr_t recipient)
+{
+	die("mcall_send_ipi is currently not implemented");
+	return 0;
+}
+
+uintptr_t mcall_clear_ipi(void)
+{
+	// only clear SSIP if no other events are pending
+	if (HLS()->device_response_queue_head == NULL) {
+		clear_csr(mip, MIP_SSIP);
+		/* Ensure the other hart sees it. */
+		mb();
+	}
+
+	return atomic_swap(&HLS()->ipi_pending, 0);
+}
+
+uintptr_t mcall_shutdown(void)
+{
+	die("mcall_shutdown is currently not implemented");
+	return 0;
+}
+
+uintptr_t mcall_set_timer(unsigned long long when)
+{
+	printk(BIOS_DEBUG, "mcall_set_timer is currently not implemented, ignoring\n");
+	return 0;
+}
+
+uintptr_t mcall_dev_req(sbi_device_message *m)
+{
+	die("mcall_dev_req is currently not implemented");
+	return 0;
+}
+
+uintptr_t mcall_dev_resp(void)
+{
+	die("mcall_dev_resp is currently not implemented");
+	return 0;
+}
+
+void hls_init(uint32_t hart_id)
+{
+	memset(HLS(), 0, sizeof(*HLS()));
+	HLS()->hart_id = hart_id;
+}
+
+uintptr_t mcall_console_putchar(uint8_t ch)
+{
+	do_putchar(ch);
+	return 0;
+}