sgi-xp: support runtime selection of xp_max_npartitions

Support runtime selection of the max number of partitions based on the
hardware being run on.

Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 92 insertions, 0 deletions

diff --git a/drivers/misc/sgi-xp/xp_sn2.c b/drivers/misc/sgi-xp/xp_sn2.c
new file mode 100644
index 00000000000..b92579356a6
--- /dev/null
+++ b/drivers/misc/sgi-xp/xp_sn2.c
@@ -0,0 +1,92 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 2008 Silicon Graphics, Inc.  All Rights Reserved.
+ */
+
+/*
+ * Cross Partition (XP) sn2-based functions.
+ *
+ *      Architecture specific implementation of common functions.
+ */
+
+#include <linux/device.h>
+#include <asm/sn/sn_sal.h>
+#include "xp.h"
+
+/*
+ * The export of xp_nofault_PIOR needs to happen here since it is defined
+ * in drivers/misc/sgi-xp/xp_nofault.S. The target of the nofault read is
+ * defined here.
+ */
+EXPORT_SYMBOL_GPL(xp_nofault_PIOR);
+
+u64 xp_nofault_PIOR_target;
+EXPORT_SYMBOL_GPL(xp_nofault_PIOR_target);
+
+/*
+ * Register a nofault code region which performs a cross-partition PIO read.
+ * If the PIO read times out, the MCA handler will consume the error and
+ * return to a kernel-provided instruction to indicate an error. This PIO read
+ * exists because it is guaranteed to timeout if the destination is down
+ * (AMO operations do not timeout on at least some CPUs on Shubs <= v1.2,
+ * which unfortunately we have to work around).
+ */
+static enum xp_retval
+xp_register_nofault_code_sn2(void)
+{
+	int ret;
+	u64 func_addr;
+	u64 err_func_addr;
+
+	func_addr = *(u64 *)xp_nofault_PIOR;
+	err_func_addr = *(u64 *)xp_error_PIOR;
+	ret = sn_register_nofault_code(func_addr, err_func_addr, err_func_addr,
+				       1, 1);
+	if (ret != 0) {
+		dev_err(xp, "can't register nofault code, error=%d\n", ret);
+		return xpSalError;
+	}
+	/*
+	 * Setup the nofault PIO read target. (There is no special reason why
+	 * SH_IPI_ACCESS was selected.)
+	 */
+	if (is_shub1())
+		xp_nofault_PIOR_target = SH1_IPI_ACCESS;
+	else if (is_shub2())
+		xp_nofault_PIOR_target = SH2_IPI_ACCESS0;
+
+	return xpSuccess;
+}
+
+void
+xp_unregister_nofault_code_sn2(void)
+{
+	u64 func_addr = *(u64 *)xp_nofault_PIOR;
+	u64 err_func_addr = *(u64 *)xp_error_PIOR;
+
+	/* unregister the PIO read nofault code region */
+	(void)sn_register_nofault_code(func_addr, err_func_addr,
+				       err_func_addr, 1, 0);
+}
+
+enum xp_retval
+xp_init_sn2(void)
+{
+	BUG_ON(!is_shub());
+
+	xp_max_npartitions = XP_MAX_NPARTITIONS_SN2;
+
+	return xp_register_nofault_code_sn2();
+}
+
+void
+xp_exit_sn2(void)
+{
+	BUG_ON(!is_shub());
+
+	xp_unregister_nofault_code_sn2();
+}
+