mailbox: Introduce Qualcomm APCS IPC driver

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.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

1 files changed, 129 insertions, 0 deletions

diff --git a/drivers/mailbox/qcom-apcs-ipc-mailbox.c b/drivers/mailbox/qcom-apcs-ipc-mailbox.c
new file mode 100644
index 000000000000..9924c6d7f05d
--- /dev/null
+++ b/drivers/mailbox/qcom-apcs-ipc-mailbox.c
@@ -0,0 +1,129 @@
+/*
+ * 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>
+#include <linux/mailbox_controller.h>
+
+#define QCOM_APCS_IPC_BITS      32
+
+struct qcom_apcs_ipc {
+        struct mbox_controller mbox;
+        struct mbox_chan mbox_chans[QCOM_APCS_IPC_BITS];
+
+        void __iomem *reg;
+        unsigned long offset;
+};
+
+static int qcom_apcs_ipc_send_data(struct mbox_chan *chan, void *data)
+{
+        struct qcom_apcs_ipc *apcs = container_of(chan->mbox,
+                                                  struct qcom_apcs_ipc, mbox);
+        unsigned long idx = (unsigned long)chan->con_priv;
+
+        writel(BIT(idx), apcs->reg);
+
+        return 0;
+}
+
+static const struct mbox_chan_ops qcom_apcs_ipc_ops = {
+        .send_data = qcom_apcs_ipc_send_data,
+};
+
+static int qcom_apcs_ipc_probe(struct platform_device *pdev)
+{
+        struct qcom_apcs_ipc *apcs;
+        struct resource *res;
+        unsigned long offset;
+        void __iomem *base;
+        unsigned long i;
+        int ret;
+
+        apcs = devm_kzalloc(&pdev->dev, sizeof(*apcs), GFP_KERNEL);
+        if (!apcs)
+                return -ENOMEM;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        base = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(base))
+                return PTR_ERR(base);
+
+        offset = (unsigned long)of_device_get_match_data(&pdev->dev);
+
+        apcs->reg = base + offset;
+
+        /* Initialize channel identifiers */
+        for (i = 0; i < ARRAY_SIZE(apcs->mbox_chans); i++)
+                apcs->mbox_chans[i].con_priv = (void *)i;
+
+        apcs->mbox.dev = &pdev->dev;
+        apcs->mbox.ops = &qcom_apcs_ipc_ops;
+        apcs->mbox.chans = apcs->mbox_chans;
+        apcs->mbox.num_chans = ARRAY_SIZE(apcs->mbox_chans);
+
+        ret = mbox_controller_register(&apcs->mbox);
+        if (ret) {
+                dev_err(&pdev->dev, "failed to register APCS IPC controller\n");
+                return ret;
+        }
+
+        platform_set_drvdata(pdev, apcs);
+
+        return 0;
+}
+
+static int qcom_apcs_ipc_remove(struct platform_device *pdev)
+{
+        struct qcom_apcs_ipc *apcs = platform_get_drvdata(pdev);
+
+        mbox_controller_unregister(&apcs->mbox);
+
+        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");