ARM: zynq: Add cpuidle support

Add cpuidle support for Xilinx Zynq.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 83 insertions, 0 deletions

diff --git a/drivers/cpuidle/cpuidle-zynq.c b/drivers/cpuidle/cpuidle-zynq.c
new file mode 100644
index 000000000000..38e03a183591
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-zynq.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2012-2013 Xilinx
+ *
+ * CPU idle support for Xilinx Zynq
+ *
+ * based on arch/arm/mach-at91/cpuidle.c
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ *
+ * The cpu idle uses wait-for-interrupt and RAM self refresh in order
+ * to implement two idle states -
+ * #1 wait-for-interrupt
+ * #2 wait-for-interrupt and RAM self refresh
+ *
+ * Maintainer: Michal Simek <michal.simek@xilinx.com>
+ */
+
+#include <linux/init.h>
+#include <linux/cpu_pm.h>
+#include <linux/cpuidle.h>
+#include <linux/of.h>
+#include <asm/proc-fns.h>
+#include <asm/cpuidle.h>
+
+#define ZYNQ_MAX_STATES         2
+
+/* Actual code that puts the SoC in different idle states */
+static int zynq_enter_idle(struct cpuidle_device *dev,
+                           struct cpuidle_driver *drv, int index)
+{
+        /* Devices must be stopped here */
+        cpu_pm_enter();
+
+        /* Add code for DDR self refresh start */
+        cpu_do_idle();
+
+        /* Add code for DDR self refresh stop */
+        cpu_pm_exit();
+
+        return index;
+}
+
+static struct cpuidle_driver zynq_idle_driver = {
+        .name = "zynq_idle",
+        .owner = THIS_MODULE,
+        .states = {
+                ARM_CPUIDLE_WFI_STATE,
+                {
+                        .enter                  = zynq_enter_idle,
+                        .exit_latency           = 10,
+                        .target_residency       = 10000,
+                        .flags                  = CPUIDLE_FLAG_TIME_VALID |
+                                                  CPUIDLE_FLAG_TIMER_STOP,
+                        .name                   = "RAM_SR",
+                        .desc                   = "WFI and RAM Self Refresh",
+                },
+        },
+        .safe_state_index = 0,
+        .state_count = ZYNQ_MAX_STATES,
+};
+
+/* Initialize CPU idle by registering the idle states */
+static int __init zynq_cpuidle_init(void)
+{
+        if (!of_machine_is_compatible("xlnx,zynq-7000"))
+                return -ENODEV;
+
+        pr_info("Xilinx Zynq CpuIdle Driver started\n");
+
+        return cpuidle_register(&zynq_idle_driver, NULL);
+}
+
+device_initcall(zynq_cpuidle_init);