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Subject[PATCH v5 05/10] soc: qcom: Add AOSS QMP communication driver
Date
The AOSS QMP driver is used to communicate with the AOSS for certain
side-channel requests, that are not enabled through the RPMh interface.

The communication is a very simple synchronous mechanism of messages
being written in message RAM and a doorbell in the AOSS is rung. As the
AOSS has processed the message length is cleared and an interrupt is
fired by the AOSS as acknowledgment.

Reviewed-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---

Changes since v4:
- None

Changes since v3:
- None

drivers/soc/qcom/Kconfig | 9 +
drivers/soc/qcom/Makefile | 1 +
drivers/soc/qcom/aoss-qmp.c | 317 ++++++++++++++++++++++++++++++
include/linux/soc/qcom/aoss-qmp.h | 14 ++
4 files changed, 341 insertions(+)
create mode 100644 drivers/soc/qcom/aoss-qmp.c
create mode 100644 include/linux/soc/qcom/aoss-qmp.h

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 1ee298f6bf17..28ab19bf8c98 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -3,6 +3,15 @@
#
menu "Qualcomm SoC drivers"

+config QCOM_AOSS_QMP
+ tristate "Qualcomm AOSS Messaging Driver"
+ depends on ARCH_QCOM || COMPILE_TEST
+ depends on MAILBOX
+ help
+ This driver provides the means for communicating with the
+ micro-controller in the AOSS, using QMP, to control certain resource
+ that are not exposed through RPMh.
+
config QCOM_COMMAND_DB
bool "Qualcomm Command DB"
depends on ARCH_QCOM || COMPILE_TEST
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index ffe519b0cb66..2c04d27fbf9e 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -1,5 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
CFLAGS_rpmh-rsc.o := -I$(src)
+obj-$(CONFIG_QCOM_AOSS_QMP) += aoss-qmp.o
obj-$(CONFIG_QCOM_GENI_SE) += qcom-geni-se.o
obj-$(CONFIG_QCOM_COMMAND_DB) += cmd-db.o
obj-$(CONFIG_QCOM_GLINK_SSR) += glink_ssr.o
diff --git a/drivers/soc/qcom/aoss-qmp.c b/drivers/soc/qcom/aoss-qmp.c
new file mode 100644
index 000000000000..86ee622cdadf
--- /dev/null
+++ b/drivers/soc/qcom/aoss-qmp.c
@@ -0,0 +1,317 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2018, Linaro Ltd
+ */
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/soc/qcom/aoss-qmp.h>
+
+#define QMP_DESC_MAGIC 0x0
+#define QMP_DESC_VERSION 0x4
+#define QMP_DESC_FEATURES 0x8
+
+#define QMP_DESC_UCORE_LINK_STATE 0xc
+#define QMP_DESC_UCORE_LINK_STATE_ACK 0x10
+#define QMP_DESC_UCORE_CH_STATE 0x14
+#define QMP_DESC_UCORE_CH_STATE_ACK 0x18
+#define QMP_DESC_UCORE_MBOX_SIZE 0x1c
+#define QMP_DESC_UCORE_MBOX_OFFSET 0x20
+
+#define QMP_DESC_MCORE_LINK_STATE 0x24
+#define QMP_DESC_MCORE_LINK_STATE_ACK 0x28
+#define QMP_DESC_MCORE_CH_STATE 0x2c
+#define QMP_DESC_MCORE_CH_STATE_ACK 0x30
+#define QMP_DESC_MCORE_MBOX_SIZE 0x34
+#define QMP_DESC_MCORE_MBOX_OFFSET 0x38
+
+#define QMP_STATE_UP 0x0000ffff
+#define QMP_STATE_DOWN 0xffff0000
+
+#define QMP_MAGIC 0x4d41494c
+#define QMP_VERSION 1
+
+/**
+ * struct qmp - driver state for QMP implementation
+ * @msgram: iomem referencing the message RAM used for communication
+ * @dev: reference to QMP device
+ * @mbox_client: mailbox client used to ring the doorbell on transmit
+ * @mbox_chan: mailbox channel used to ring the doorbell on transmit
+ * @offset: offset within @msgram where messages should be written
+ * @size: maximum size of the messages to be transmitted
+ * @event: wait_queue for synchronization with the IRQ
+ * @tx_lock: provides syncrhonization between multiple callers of qmp_send()
+ * @pd_pdev: platform device for the power-domain child device
+ */
+struct qmp {
+ void __iomem *msgram;
+ struct device *dev;
+
+ struct mbox_client mbox_client;
+ struct mbox_chan *mbox_chan;
+
+ size_t offset;
+ size_t size;
+
+ wait_queue_head_t event;
+
+ struct mutex tx_lock;
+
+ struct platform_device *pd_pdev;
+};
+
+static void qmp_kick(struct qmp *qmp)
+{
+ mbox_send_message(qmp->mbox_chan, NULL);
+ mbox_client_txdone(qmp->mbox_chan, 0);
+}
+
+static bool qmp_magic_valid(struct qmp *qmp)
+{
+ return readl(qmp->msgram + QMP_DESC_MAGIC) == QMP_MAGIC;
+}
+
+static bool qmp_link_acked(struct qmp *qmp)
+{
+ return readl(qmp->msgram + QMP_DESC_MCORE_LINK_STATE_ACK) == QMP_STATE_UP;
+}
+
+static bool qmp_mcore_channel_acked(struct qmp *qmp)
+{
+ return readl(qmp->msgram + QMP_DESC_MCORE_CH_STATE_ACK) == QMP_STATE_UP;
+}
+
+static bool qmp_ucore_channel_up(struct qmp *qmp)
+{
+ return readl(qmp->msgram + QMP_DESC_UCORE_CH_STATE) == QMP_STATE_UP;
+}
+
+static int qmp_open(struct qmp *qmp)
+{
+ int ret;
+ u32 val;
+
+ ret = wait_event_timeout(qmp->event, qmp_magic_valid(qmp), HZ);
+ if (!ret) {
+ dev_err(qmp->dev, "QMP magic doesn't match\n");
+ return -ETIMEDOUT;
+ }
+
+ val = readl(qmp->msgram + QMP_DESC_VERSION);
+ if (val != QMP_VERSION) {
+ dev_err(qmp->dev, "unsupported QMP version %d\n", val);
+ return -EINVAL;
+ }
+
+ qmp->offset = readl(qmp->msgram + QMP_DESC_MCORE_MBOX_OFFSET);
+ qmp->size = readl(qmp->msgram + QMP_DESC_MCORE_MBOX_SIZE);
+ if (!qmp->size) {
+ dev_err(qmp->dev, "invalid mailbox size 0x%zx\n", qmp->size);
+ return -EINVAL;
+ }
+
+ /* Ack remote core's link state */
+ val = readl(qmp->msgram + QMP_DESC_UCORE_LINK_STATE);
+ writel(val, qmp->msgram + QMP_DESC_UCORE_LINK_STATE_ACK);
+
+ /* Set local core's link state to up */
+ writel(QMP_STATE_UP, qmp->msgram + QMP_DESC_MCORE_LINK_STATE);
+
+ qmp_kick(qmp);
+
+ ret = wait_event_timeout(qmp->event, qmp_link_acked(qmp), HZ);
+ if (!ret) {
+ dev_err(qmp->dev, "ucore didn't ack link\n");
+ goto timeout_close_link;
+ }
+
+ writel(QMP_STATE_UP, qmp->msgram + QMP_DESC_MCORE_CH_STATE);
+
+ ret = wait_event_timeout(qmp->event, qmp_ucore_channel_up(qmp), HZ);
+ if (!ret) {
+ dev_err(qmp->dev, "ucore didn't open channel\n");
+ goto timeout_close_channel;
+ }
+
+ /* Ack remote core's channel state */
+ val = readl(qmp->msgram + QMP_DESC_UCORE_CH_STATE);
+ writel(val, qmp->msgram + QMP_DESC_UCORE_CH_STATE_ACK);
+
+ qmp_kick(qmp);
+
+ ret = wait_event_timeout(qmp->event, qmp_mcore_channel_acked(qmp), HZ);
+ if (!ret) {
+ dev_err(qmp->dev, "ucore didn't ack channel\n");
+ goto timeout_close_channel;
+ }
+
+ return 0;
+
+timeout_close_channel:
+ writel(QMP_STATE_DOWN, qmp->msgram + QMP_DESC_MCORE_CH_STATE);
+
+timeout_close_link:
+ writel(QMP_STATE_DOWN, qmp->msgram + QMP_DESC_MCORE_LINK_STATE);
+ qmp_kick(qmp);
+
+ return -ETIMEDOUT;
+}
+
+static void qmp_close(struct qmp *qmp)
+{
+ writel(QMP_STATE_DOWN, qmp->msgram + QMP_DESC_MCORE_CH_STATE);
+ writel(QMP_STATE_DOWN, qmp->msgram + QMP_DESC_MCORE_LINK_STATE);
+ qmp_kick(qmp);
+}
+
+static irqreturn_t qmp_intr(int irq, void *data)
+{
+ struct qmp *qmp = data;
+
+ wake_up_interruptible_all(&qmp->event);
+
+ return IRQ_HANDLED;
+}
+
+static bool qmp_message_empty(struct qmp *qmp)
+{
+ return readl(qmp->msgram + qmp->offset) == 0;
+}
+
+/**
+ * qmp_send() - send a message to the AOSS
+ * @qmp: qmp context
+ * @data: message to be sent
+ * @len: length of the message
+ *
+ * Transmit @data to AOSS and wait for the AOSS to acknowledge the message.
+ * @len must be a multiple of 4 and not longer than the mailbox size. Access is
+ * synchronized by this implementation.
+ *
+ * Return: 0 on success, negative errno on failure
+ */
+int qmp_send(struct qmp *qmp, const void *data, size_t len)
+{
+ int ret;
+
+ if (WARN_ON(len + sizeof(u32) > qmp->size))
+ return -EINVAL;
+
+ if (WARN_ON(len % sizeof(u32)))
+ return -EINVAL;
+
+ mutex_lock(&qmp->tx_lock);
+
+ /* The message RAM only implements 32-bit accesses */
+ __iowrite32_copy(qmp->msgram + qmp->offset + sizeof(u32),
+ data, len / sizeof(u32));
+ writel(len, qmp->msgram + qmp->offset);
+ qmp_kick(qmp);
+
+ ret = wait_event_interruptible_timeout(qmp->event,
+ qmp_message_empty(qmp), HZ);
+ if (!ret) {
+ dev_err(qmp->dev, "ucore did not ack channel\n");
+ ret = -ETIMEDOUT;
+
+ /* Clear message from buffer */
+ writel(0, qmp->msgram + qmp->offset);
+ } else {
+ ret = 0;
+ }
+
+ mutex_unlock(&qmp->tx_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL(qmp_send);
+
+static int qmp_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ struct qmp *qmp;
+ int irq;
+ int ret;
+
+ qmp = devm_kzalloc(&pdev->dev, sizeof(*qmp), GFP_KERNEL);
+ if (!qmp)
+ return -ENOMEM;
+
+ qmp->dev = &pdev->dev;
+ init_waitqueue_head(&qmp->event);
+ mutex_init(&qmp->tx_lock);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ qmp->msgram = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(qmp->msgram))
+ return PTR_ERR(qmp->msgram);
+
+ qmp->mbox_client.dev = &pdev->dev;
+ qmp->mbox_client.knows_txdone = true;
+ qmp->mbox_chan = mbox_request_channel(&qmp->mbox_client, 0);
+ if (IS_ERR(qmp->mbox_chan)) {
+ dev_err(&pdev->dev, "failed to acquire ipc mailbox\n");
+ return PTR_ERR(qmp->mbox_chan);
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ ret = devm_request_irq(&pdev->dev, irq, qmp_intr, IRQF_ONESHOT,
+ "aoss-qmp", qmp);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to request interrupt\n");
+ mbox_free_channel(qmp->mbox_chan);
+ return ret;
+ }
+
+ ret = qmp_open(qmp);
+ if (ret < 0) {
+ mbox_free_channel(qmp->mbox_chan);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, qmp);
+
+ if (of_property_read_bool(pdev->dev.of_node, "#power-domain-cells")) {
+ qmp->pd_pdev = platform_device_register_data(&pdev->dev,
+ "aoss_qmp_pd",
+ PLATFORM_DEVID_NONE,
+ NULL, 0);
+ if (IS_ERR(qmp->pd_pdev))
+ dev_err(&pdev->dev, "failed to register AOSS PD\n");
+ }
+
+ return 0;
+}
+
+static int qmp_remove(struct platform_device *pdev)
+{
+ struct qmp *qmp = platform_get_drvdata(pdev);
+
+ platform_device_unregister(qmp->pd_pdev);
+
+ mbox_free_channel(qmp->mbox_chan);
+ qmp_close(qmp);
+
+ return 0;
+}
+
+static const struct of_device_id qmp_dt_match[] = {
+ { .compatible = "qcom,sdm845-aoss-qmp", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, qmp_dt_match);
+
+static struct platform_driver qmp_driver = {
+ .driver = {
+ .name = "aoss_qmp",
+ .of_match_table = qmp_dt_match,
+ },
+ .probe = qmp_probe,
+ .remove = qmp_remove,
+};
+module_platform_driver(qmp_driver);
+
+MODULE_DESCRIPTION("Qualcomm AOSS QMP driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/soc/qcom/aoss-qmp.h b/include/linux/soc/qcom/aoss-qmp.h
new file mode 100644
index 000000000000..a2ac891d7fd4
--- /dev/null
+++ b/include/linux/soc/qcom/aoss-qmp.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2018, Linaro Ltd
+ */
+#ifndef __AOP_QMP_H__
+#define __AOP_QMP_H__
+
+#include <linux/types.h>
+
+struct qmp;
+
+int qmp_send(struct qmp *qmp, const void *data, size_t len);
+
+#endif
--
2.18.0
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