[ARM] 4184/1: iop: cp6 access handler (undef_hook)
Enable svc access to cp6 via an undefined instruction hook. Do not enable
access for usr code.
This patch also makes iop13xx select PLAT_IOP, this requires a small change
to drivers/i2c/busses/i2c-iop3xx.c.
Per Lennert Buytenhek's note, the cp6 trap routine is moved to arch/arm/plat-iop
Per Nicolas Pitre's note, the cp_wait is skipped since the latency to
return to the faulting function is longer than cp_wait.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/plat-iop/cp6.c b/arch/arm/plat-iop/cp6.c
new file mode 100644
index 0000000..9612a87
--- /dev/null
+++ b/arch/arm/plat-iop/cp6.c
@@ -0,0 +1,50 @@
+/*
+ * IOP Coprocessor-6 access handler
+ * Copyright (c) 2006, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ */
+#include <linux/init.h>
+#include <asm/traps.h>
+
+static int cp6_trap(struct pt_regs *regs, unsigned int instr)
+{
+ u32 temp;
+
+ /* enable cp6 access */
+ asm volatile (
+ "mrc p15, 0, %0, c15, c1, 0\n\t"
+ "orr %0, %0, #(1 << 6)\n\t"
+ "mcr p15, 0, %0, c15, c1, 0\n\t"
+ : "=r"(temp));
+
+ return 0;
+}
+
+/* permit kernel space cp6 access
+ * deny user space cp6 access
+ */
+static struct undef_hook cp6_hook = {
+ .instr_mask = 0x0f000ff0,
+ .instr_val = 0x0e000610,
+ .cpsr_mask = MODE_MASK,
+ .cpsr_val = SVC_MODE,
+ .fn = cp6_trap,
+};
+
+void __init iop_init_cp6_handler(void)
+{
+ register_undef_hook(&cp6_hook);
+}