Implement reset handler for remoteproc
Use the reset controller driver mechanism to control the Ethos-U
subsystem remoteproc driver.
Change-Id: If180d5b922f8b1cd245af7f922911c17ecd313a3
diff --git a/remoteproc/ethosu_bridge_reset.c b/remoteproc/ethosu_bridge_reset.c
new file mode 100644
index 0000000..7f73ee7
--- /dev/null
+++ b/remoteproc/ethosu_bridge_reset.c
@@ -0,0 +1,157 @@
+/*
+ * Copyright (c) 2021 Arm Limited. All rights reserved.
+ *
+ * This program is free software and is provided to you under the terms of the
+ * GNU General Public License version 2 as published by the Free Software
+ * Foundation, and any use by you of this program is subject to the terms
+ * of such GNU licence.
+ *
+ * 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. 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, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ */
+
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+
+#define ETHOSU_BRIDGE_RESET_DRIVER_VERSION "0.0.1"
+
+struct ethosu_reset {
+ struct reset_controller_dev rst;
+ struct device *dev;
+ void __iomem *base;
+};
+
+#define ETHOSU_BRIDGE_ID(base) (base)
+#define ETHOSU_BRIDGE_CTRL(base) ((base) + 0x100)
+
+#define ETHOSU_BRIDGE_WAIT_ENABLE (0x2)
+#define ETHOSU_BRIDGE_RESET (0x1)
+
+static void __iomem *bridge_verify_and_remap(struct device *dev,
+ struct resource *res)
+{
+ void __iomem *base = devm_ioremap_resource(dev, res);
+ u32 id;
+ u16 magic;
+ u8 minor;
+ u8 major;
+
+ if (IS_ERR(base))
+ return base;
+
+ id = readl(ETHOSU_BRIDGE_ID(base));
+ magic = id & 0x0000ffff;
+ minor = (id & 0x00ff0000) >> 16;
+ major = (id & 0xff000000) >> 24;
+
+ dev_dbg(dev, "verifying bridge %d.%d", major, minor);
+
+ if (magic != 0xBD9E)
+ return IOMEM_ERR_PTR(-EINVAL);
+
+ return base;
+}
+
+int ethosu_bridge_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct ethosu_reset *ethosu = container_of(rcdev, struct ethosu_reset,
+ rst);
+
+ /* pull reset */
+ dev_dbg(ethosu->dev, "Asserting reset");
+
+ /* set wait and reset */
+ writel(ETHOSU_BRIDGE_WAIT_ENABLE | ETHOSU_BRIDGE_RESET,
+ ETHOSU_BRIDGE_CTRL(ethosu->base));
+
+ return 0;
+}
+
+int ethosu_bridge_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct ethosu_reset *ethosu = container_of(rcdev, struct ethosu_reset,
+ rst);
+
+ /* release reset */
+ dev_dbg(ethosu->dev, "Deasserting reset");
+ writel(~ETHOSU_BRIDGE_WAIT_ENABLE & ETHOSU_BRIDGE_RESET,
+ ETHOSU_BRIDGE_CTRL(ethosu->base));
+
+ return 0;
+}
+
+static struct reset_control_ops ethosu_reset_bridge_ops = {
+ .assert = ethosu_bridge_assert,
+ .deassert = ethosu_bridge_deassert,
+};
+
+static const struct of_device_id ethosu_reset_match[] = {
+ { .compatible = "arm,ethosu-bridge-reset", .data = 0 },
+ { /* sentinel */ },
+};
+
+static int ethosu_bridge_reset_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct ethosu_reset *ethosu;
+ struct resource *res;
+
+ ethosu = devm_kzalloc(&pdev->dev, sizeof(*ethosu), GFP_KERNEL);
+ if (!ethosu)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+ ethosu->base = bridge_verify_and_remap(dev, res);
+ ethosu->dev = dev;
+
+ if (IS_ERR(ethosu->base))
+ return PTR_ERR(ethosu->base);
+
+ platform_set_drvdata(pdev, ethosu);
+
+ ethosu->rst.owner = THIS_MODULE;
+ ethosu->rst.nr_resets = 1;
+ ethosu->rst.ops = ðosu_reset_bridge_ops;
+ ethosu->rst.of_node = pdev->dev.of_node;
+
+ dev_dbg(dev, "registering to reset controller core");
+
+ return devm_reset_controller_register(dev, ðosu->rst);
+}
+
+static int ethosu_bridge_reset_remove(struct platform_device *pdev)
+{
+ return 0;
+}
+
+static struct platform_driver ethosu_reset_driver = {
+ .probe = ethosu_bridge_reset_probe,
+ .remove = ethosu_bridge_reset_remove,
+ .driver = {
+ .name = "ethosu-bridge-reset",
+ .of_match_table = of_match_ptr(ethosu_reset_match),
+ },
+};
+
+module_platform_driver(ethosu_reset_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Arm Ltd");
+MODULE_DESCRIPTION("Arm Ethos-U NPU Bridge Reset Driver");
+MODULE_VERSION(ETHOSU_BRIDGE_RESET_DRIVER_VERSION);