This implements a driver that exposes the IPC bits found in the APCS
Global block in various Qualcomm platforms. The bits are used to signal
inter-processor communication signals from the application CPU to other
masters.
The driver implements the "doorbell" binding and could be used as basis
for a new Linux framework, if found useful outside Qualcomm.
Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
---
Changes since v2:
- New driver
drivers/soc/qcom/Kconfig | 8 ++
drivers/soc/qcom/Makefile | 1 +
drivers/soc/qcom/apcs-ipc.c | 182 ++++++++++++++++++++++++++++++++++++++
include/linux/soc/qcom/apcs_ipc.h | 26 ++++++
4 files changed, 217 insertions(+)
create mode 100644 drivers/soc/qcom/apcs-ipc.c
create mode 100644 include/linux/soc/qcom/apcs_ipc.h
diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 78b1bb7bcf20..4113da81d18b 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -1,6 +1,14 @@
#
# QCOM Soc drivers
#
+config QCOM_APCS_IPC
+ tristate "Qualcomm APCS IPC driver"
+ depends on ARCH_QCOM
+ help
+ Say y here to enable support for the APCS IPC doorbell driver,
+ providing an interface for invoking the inter-process communication
+ signals from the application processor to other masters.
+
config QCOM_GSBI
tristate "QCOM General Serial Bus Interface"
depends on ARCH_QCOM
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 1f30260b06b8..e15b33e5a630 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -1,3 +1,4 @@
+obj-$(CONFIG_QCOM_APCS_IPC) += apcs-ipc.o
obj-$(CONFIG_QCOM_GSBI) += qcom_gsbi.o
obj-$(CONFIG_QCOM_MDT_LOADER) += mdt_loader.o
obj-$(CONFIG_QCOM_PM) += spm.o
diff --git a/drivers/soc/qcom/apcs-ipc.c b/drivers/soc/qcom/apcs-ipc.c
new file mode 100644
index 000000000000..ea835cb08657
--- /dev/null
+++ b/drivers/soc/qcom/apcs-ipc.c
@@ -0,0 +1,182 @@
+/*
+ * Copyright (c) 2017, Linaro Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+static struct platform_driver qcom_apcs_ipc_driver;
+
+struct qcom_apcs_ipc {
+ struct device *dev;
+
+ void __iomem *base;
+ unsigned long offset;
+};
+
+struct qcom_apcs_ipc_bell {
+ struct qcom_apcs_ipc *apcs;
+ unsigned int bit;
+};
+
+static void qcom_apcs_ipc_release(struct device *dev, void *res)
+{
+ struct qcom_apcs_ipc_bell *bell = res;
+ struct qcom_apcs_ipc *apcs = bell->apcs;
+
+ put_device(apcs->dev);
+}
+
+/**
+ * qcom_apcs_ipc_get() - acquire a handle to a doorbell
+ * @dev: client device handle
+ * @id: identifier of the doorbell
+ *
+ * Returns a doorbell reference, or negative errno on failure.
+ */
+struct qcom_apcs_ipc_bell *devm_qcom_apcs_ipc_get(struct device *dev,
+ const char *id)
+{
+ struct qcom_apcs_ipc_bell *bell;
+ struct platform_device *pdev;
+ struct of_phandle_args args;
+ int index = 0;
+ int ret;
+
+ if (id) {
+ index = of_property_match_string(dev->of_node,
+ "doorbell-names", id);
+ if (index < 0)
+ return ERR_PTR(index);
+ }
+
+ ret = of_parse_phandle_with_args(dev->of_node, "doorbells",
+ "#doorbell-cells", index, &args);
+ if (ret) {
+ dev_err(dev, "unable to resolve doorbell\n");
+ return ERR_PTR(-ENODEV);
+ }
+
+ pdev = of_find_device_by_node(args.np);
+ of_node_put(args.np);
+
+ if (!pdev)
+ return ERR_PTR(-EPROBE_DEFER);
+
+ if (args.args[0] >= 32) {
+ dev_err(dev, "invalid doorbell requested\n");
+ ret = -EINVAL;
+ goto release_device;
+ }
+
+ if (pdev->dev.driver != &qcom_apcs_ipc_driver.driver) {
+ dev_err(dev, "failed to acquire apcs ipc driver\n");
+ ret = -EINVAL;
+ goto release_device;
+ }
+
+ bell = devres_alloc(qcom_apcs_ipc_release, sizeof(*bell), GFP_KERNEL);
+ if (!bell) {
+ ret = -ENOMEM;
+ goto release_device;
+ }
+
+ bell->apcs = platform_get_drvdata(pdev);
+ bell->bit = args.args[0];
+
+ devres_add(dev, bell);
+
+ return bell;
+
+release_device:
+ put_device(&pdev->dev);
+
+ return ERR_PTR(ret);
+
+}
+EXPORT_SYMBOL_GPL(devm_qcom_apcs_ipc_get);
+
+/**
+ * qcom_apcs_ipc_ring() - ring the doorbell
+ * @bell: doorbell to ring
+ */
+void qcom_apcs_ipc_ring(struct qcom_apcs_ipc_bell *bell)
+{
+ struct qcom_apcs_ipc *apcs = bell->apcs;
+
+ writel(BIT(bell->bit), apcs->base + apcs->offset);
+}
+EXPORT_SYMBOL_GPL(qcom_apcs_ipc_ring);
+
+static int qcom_apcs_ipc_probe(struct platform_device *pdev)
+{
+ struct qcom_apcs_ipc *apcs;
+ struct resource *res;
+
+ apcs = devm_kzalloc(&pdev->dev, sizeof(*apcs), GFP_KERNEL);
+ if (!apcs)
+ return -ENOMEM;
+
+ apcs->dev = &pdev->dev;
+ apcs->offset = (unsigned long)of_device_get_match_data(&pdev->dev);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ apcs->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(apcs->base))
+ return PTR_ERR(apcs->base);
+
+ platform_set_drvdata(pdev, apcs);
+
+ return 0;
+}
+
+static int qcom_apcs_ipc_remove(struct platform_device *pdev)
+{
+ return 0;
+}
+
+/* .data is the offset of the ipc register within the global block */
+static const struct of_device_id qcom_apcs_ipc_of_match[] = {
+ { .compatible = "qcom,msm8916-apcs-kpss-global", .data = (void *)8 },
+ { .compatible = "qcom,msm8996-apcs-hmss-global", .data = (void *)16 },
+ {}
+};
+MODULE_DEVICE_TABLE(of, qcom_apcs_ipc_of_match);
+
+static struct platform_driver qcom_apcs_ipc_driver = {
+ .probe = qcom_apcs_ipc_probe,
+ .remove = qcom_apcs_ipc_remove,
+ .driver = {
+ .name = "qcom_apcs_ipc",
+ .of_match_table = qcom_apcs_ipc_of_match,
+ },
+};
+
+static int __init qcom_apcs_ipc_init(void)
+{
+ return platform_driver_register(&qcom_apcs_ipc_driver);
+}
+postcore_initcall(qcom_apcs_ipc_init);
+
+static void __exit qcom_apcs_ipc_exit(void)
+{
+ platform_driver_unregister(&qcom_apcs_ipc_driver);
+}
+module_exit(qcom_apcs_ipc_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Qualcomm APCS IPC driver");
diff --git a/include/linux/soc/qcom/apcs_ipc.h b/include/linux/soc/qcom/apcs_ipc.h
new file mode 100644
index 000000000000..72be77555261
--- /dev/null
+++ b/include/linux/soc/qcom/apcs_ipc.h
@@ -0,0 +1,26 @@
+#ifndef __QCOM_APCS_IPC_H__
+#define __QCOM_APCS_IPC_H__
+
+#include <linux/err.h>
+
+struct device;
+struct qcom_apcs_ipc_bell;
+
+#if IS_ENABLED(CONFIG_QCOM_APCS_IPC)
+
+struct qcom_apcs_ipc_bell *devm_qcom_apcs_ipc_get(struct device *dev,
+ const char *id);
+void qcom_apcs_ipc_ring(struct qcom_apcs_ipc_bell *bell);
+
+#else
+
+static inline struct qcom_apcs_ipc_bell *devm_qcom_apcs_ipc_get(struct device *dev,
+ const char *id)
+{
+ return ERR_PTR(-EINVAL);
+}
+
+static inline void qcom_apcs_ipc_ring(struct qcom_apcs_ipc_bell *bell) {}
+
+#endif
+#endif
--
2.12.0
--
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