[PATCH V5 2/5] mailbox: Add support for QTI CPUCP mailbox controller

Sibi Sankar
2024-06-03T20:59:41Z

Add support for CPUSS Control Processor (CPUCP) mailbox controller,
this driver enables communication between AP and CPUCP by acting as
a doorbell between them.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
---

v4:
* Move val, flag and chan to local loop variables. [Jassi]
* Add cpucp mailbox to the MAINTAINERS file. [Jassi]
* Move to core_initcall. [Konrad]
* Skip explicitly setting txdone_irq/txdone_poll to zero. [Konrad]

MAINTAINERS | 7 ++
drivers/mailbox/Kconfig | 8 ++
drivers/mailbox/Makefile | 2 +
drivers/mailbox/qcom-cpucp-mbox.c | 187 ++++++++++++++++++++++++++++++
4 files changed, 204 insertions(+)
create mode 100644 drivers/mailbox/qcom-cpucp-mbox.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 332f452645d6..d1e92039dd8b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18495,6 +18495,13 @@ S: Maintained
F: Documentation/devicetree/bindings/power/avs/qcom,cpr.yaml
F: drivers/pmdomain/qcom/cpr.c

+QUALCOMM CPUCP MAILBOX DRIVER
+M: Sibi Sankar <quic_sibis@quicinc.com>
+L: linux-arm-msm@vger.kernel.org
+S: Supported
+F: Documentation/devicetree/bindings/mailbox/qcom,cpucp-mbox.yaml
+F: drivers/mailbox/qcom-cpucp-mbox.c
+
QUALCOMM CPUFREQ DRIVER MSM8996/APQ8096
M: Ilia Lin <ilia.lin@kernel.org>
L: linux-pm@vger.kernel.org
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index 3b8842c4a340..181b51c577f6 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -276,6 +276,14 @@ config SPRD_MBOX
to send message between application processors and MCU. Say Y here if
you want to build the Spreatrum mailbox controller driver.

+config QCOM_CPUCP_MBOX
+ tristate "Qualcomm Technologies, Inc. CPUCP mailbox driver"
+ depends on ARCH_QCOM || COMPILE_TEST
+ help
+ Qualcomm Technologies, Inc. CPUSS Control Processor (CPUCP) mailbox
+ controller driver enables communication between AP and CPUCP. Say
+ Y here if you want to build this driver.
+
config QCOM_IPCC
tristate "Qualcomm Technologies, Inc. IPCC driver"
depends on ARCH_QCOM || COMPILE_TEST
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 5cf2f54debaf..3c3c27d54c13 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -61,4 +61,6 @@ obj-$(CONFIG_SUN6I_MSGBOX) += sun6i-msgbox.o

obj-$(CONFIG_SPRD_MBOX) += sprd-mailbox.o

+obj-$(CONFIG_QCOM_CPUCP_MBOX) += qcom-cpucp-mbox.o
+
obj-$(CONFIG_QCOM_IPCC) += qcom-ipcc.o
diff --git a/drivers/mailbox/qcom-cpucp-mbox.c b/drivers/mailbox/qcom-cpucp-mbox.c
new file mode 100644
index 000000000000..e5437c294803
--- /dev/null
+++ b/drivers/mailbox/qcom-cpucp-mbox.c
@@ -0,0 +1,187 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2024, Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define APSS_CPUCP_IPC_CHAN_SUPPORTED 3
+#define APSS_CPUCP_MBOX_CMD_OFF 0x4
+
+/* Tx Registers */
+#define APSS_CPUCP_TX_MBOX_CMD(i) (0x100 + ((i) * 8))
+
+/* Rx Registers */
+#define APSS_CPUCP_RX_MBOX_CMD(i) (0x100 + ((i) * 8))
+#define APSS_CPUCP_RX_MBOX_MAP 0x4000
+#define APSS_CPUCP_RX_MBOX_STAT 0x4400
+#define APSS_CPUCP_RX_MBOX_CLEAR 0x4800
+#define APSS_CPUCP_RX_MBOX_EN 0x4c00
+#define APSS_CPUCP_RX_MBOX_CMD_MASK GENMASK_ULL(63, 0)
+
+/**
+ * struct qcom_cpucp_mbox - Holder for the mailbox driver
+ * @chans: The mailbox channel
+ * @mbox: The mailbox controller
+ * @tx_base: Base address of the CPUCP tx registers
+ * @rx_base: Base address of the CPUCP rx registers
+ */
+struct qcom_cpucp_mbox {
+ struct mbox_chan chans[APSS_CPUCP_IPC_CHAN_SUPPORTED];
+ struct mbox_controller mbox;
+ void __iomem *tx_base;
+ void __iomem *rx_base;
+};
+
+static inline int channel_number(struct mbox_chan *chan)
+{
+ return chan - chan->mbox->chans;
+}
+
+static irqreturn_t qcom_cpucp_mbox_irq_fn(int irq, void *data)
+{
+ struct qcom_cpucp_mbox *cpucp = data;
+ u64 status;
+ int i;
+
+ status = readq(cpucp->rx_base + APSS_CPUCP_RX_MBOX_STAT);
+
+ for_each_set_bit(i, (unsigned long *)&status, APSS_CPUCP_IPC_CHAN_SUPPORTED) {
+ u32 val = readl(cpucp->rx_base + APSS_CPUCP_RX_MBOX_CMD(i) + APSS_CPUCP_MBOX_CMD_OFF);
+ struct mbox_chan *chan = &cpucp->chans[i];
+ unsigned long flags;
+
+ /* Provide mutual exclusion with changes to chan->cl */
+ spin_lock_irqsave(&chan->lock, flags);
+ if (chan->cl)
+ mbox_chan_received_data(chan, &val);
+ writeq(BIT(i), cpucp->rx_base + APSS_CPUCP_RX_MBOX_CLEAR);
+ spin_unlock_irqrestore(&chan->lock, flags);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int qcom_cpucp_mbox_startup(struct mbox_chan *chan)
+{
+ struct qcom_cpucp_mbox *cpucp = container_of(chan->mbox, struct qcom_cpucp_mbox, mbox);
+ unsigned long chan_id = channel_number(chan);
+ u64 val;
+
+ val = readq(cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
+ val |= BIT(chan_id);
+ writeq(val, cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
+
+ return 0;
+}
+
+static void qcom_cpucp_mbox_shutdown(struct mbox_chan *chan)
+{
+ struct qcom_cpucp_mbox *cpucp = container_of(chan->mbox, struct qcom_cpucp_mbox, mbox);
+ unsigned long chan_id = channel_number(chan);
+ u64 val;
+
+ val = readq(cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
+ val &= ~BIT(chan_id);
+ writeq(val, cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
+}
+
+static int qcom_cpucp_mbox_send_data(struct mbox_chan *chan, void *data)
+{
+ struct qcom_cpucp_mbox *cpucp = container_of(chan->mbox, struct qcom_cpucp_mbox, mbox);
+ unsigned long chan_id = channel_number(chan);
+ u32 *val = data;
+
+ writel(*val, cpucp->tx_base + APSS_CPUCP_TX_MBOX_CMD(chan_id) + APSS_CPUCP_MBOX_CMD_OFF);
+
+ return 0;
+}
+
+static const struct mbox_chan_ops qcom_cpucp_mbox_chan_ops = {
+ .startup = qcom_cpucp_mbox_startup,
+ .send_data = qcom_cpucp_mbox_send_data,
+ .shutdown = qcom_cpucp_mbox_shutdown
+};
+
+static int qcom_cpucp_mbox_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct qcom_cpucp_mbox *cpucp;
+ struct mbox_controller *mbox;
+ int irq, ret;
+
+ cpucp = devm_kzalloc(dev, sizeof(*cpucp), GFP_KERNEL);
+ if (!cpucp)
+ return -ENOMEM;
+
+ cpucp->rx_base = devm_of_iomap(dev, dev->of_node, 0, NULL);
+ if (IS_ERR(cpucp->rx_base))
+ return PTR_ERR(cpucp->rx_base);
+
+ cpucp->tx_base = devm_of_iomap(dev, dev->of_node, 1, NULL);
+ if (IS_ERR(cpucp->tx_base))
+ return PTR_ERR(cpucp->tx_base);
+
+ writeq(0, cpucp->rx_base + APSS_CPUCP_RX_MBOX_EN);
+ writeq(0, cpucp->rx_base + APSS_CPUCP_RX_MBOX_CLEAR);
+ writeq(0, cpucp->rx_base + APSS_CPUCP_RX_MBOX_MAP);
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ ret = devm_request_irq(dev, irq, qcom_cpucp_mbox_irq_fn,
+ IRQF_TRIGGER_HIGH, "apss_cpucp_mbox", cpucp);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "Failed to register irq: %d\n", irq);
+
+ writeq(APSS_CPUCP_RX_MBOX_CMD_MASK, cpucp->rx_base + APSS_CPUCP_RX_MBOX_MAP);
+
+ mbox = &cpucp->mbox;
+ mbox->dev = dev;
+ mbox->num_chans = APSS_CPUCP_IPC_CHAN_SUPPORTED;
+ mbox->chans = cpucp->chans;
+ mbox->ops = &qcom_cpucp_mbox_chan_ops;
+
+ ret = devm_mbox_controller_register(dev, mbox);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to create mailbox\n");
+
+ return 0;
+}
+
+static const struct of_device_id qcom_cpucp_mbox_of_match[] = {
+ { .compatible = "qcom,x1e80100-cpucp-mbox" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, qcom_cpucp_mbox_of_match);
+
+static struct platform_driver qcom_cpucp_mbox_driver = {
+ .probe = qcom_cpucp_mbox_probe,
+ .driver = {
+ .name = "qcom_cpucp_mbox",
+ .of_match_table = qcom_cpucp_mbox_of_match,
+ },
+};
+
+static int __init qcom_cpucp_mbox_init(void)
+{
+ return platform_driver_register(&qcom_cpucp_mbox_driver);
+}
+core_initcall(qcom_cpucp_mbox_init);
+
+static void __exit qcom_cpucp_mbox_exit(void)
+{
+ platform_driver_unregister(&qcom_cpucp_mbox_driver);
+}
+module_exit(qcom_cpucp_mbox_exit);
+
+MODULE_DESCRIPTION("QTI CPUCP MBOX Driver");
+MODULE_LICENSE("GPL");
--
2.34.1