[PATCH v5 31/34] Intel Keem Bay XLink SMBus driver

mgross
2021-02-06T04:27:17Z

From: Ramya P Karanth <ramya.p.karanth@intel.com>

Adds XLink SMBus driver for Intel Keem Bay SoC.

Xlink-smbus driver is a logical SMBus adapter which uses Xlink
(xlink-pcie) protocol as an interface. Keem Bay(s) vision accelerators
are connected to the server via PCI interface. The Server needs to know
the temperature of the Soc and the source to get the temperature can be
either on board sensors or on chip sensors. The sensors are ideally
connected over i2c bus of the Soc and the server does not have access to
sensors present in the PCB. With this xlink-smbus interfaces, server
access the on board/on chip sensors via xlink smbus adapter.

Signed-off-by: Ramya P Karanth <ramya.p.karanth@intel.com>
Signed-off-by: Mark Gross <mgross@linux.intel.com>
---
Documentation/i2c/busses/index.rst | 1 +
.../i2c/busses/intel-xlink-smbus.rst | 71 +++
drivers/misc/Kconfig | 1 +
drivers/misc/Makefile | 1 +
drivers/misc/xlink-smbus/Kconfig | 26 +
drivers/misc/xlink-smbus/Makefile | 5 +
drivers/misc/xlink-smbus/xlink-smbus.c | 467 ++++++++++++++++++
7 files changed, 572 insertions(+)
create mode 100644 Documentation/i2c/busses/intel-xlink-smbus.rst
create mode 100644 drivers/misc/xlink-smbus/Kconfig
create mode 100644 drivers/misc/xlink-smbus/Makefile
create mode 100644 drivers/misc/xlink-smbus/xlink-smbus.c

diff --git a/Documentation/i2c/busses/index.rst b/Documentation/i2c/busses/index.rst
index 5e4077b08d86..6ce4a740f616 100644
--- a/Documentation/i2c/busses/index.rst
+++ b/Documentation/i2c/busses/index.rst
@@ -29,4 +29,5 @@ I2C Bus Drivers
i2c-taos-evm
i2c-viapro
i2c-via
+ intel-xlink-smbus.rst
scx200_acb
diff --git a/Documentation/i2c/busses/intel-xlink-smbus.rst b/Documentation/i2c/busses/intel-xlink-smbus.rst
new file mode 100644
index 000000000000..ab87d18051b4
--- /dev/null
+++ b/Documentation/i2c/busses/intel-xlink-smbus.rst
@@ -0,0 +1,71 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==========================
+Kernel driver: xlink_smbus
+==========================
+
+Supported chips:
+ * Intel Edge.AI Computer Vision platforms: Keem Bay
+
+ Sufix: Bay
+
+ Slave address: The address is selectable by device-tree. (TBD)
+
+Authors:
+ - Raja Subramanian, Lakshmi Bai <lakshmi.bai.raja.subramanian@intel.com>
+ - Thalaiappan, Rathina <rathina.thalaiappan@intel.com>
+ - Karanth, Ramya P <ramya.p.karanth@intel.com>
+
+Description
+===========
+The Intel Edge.AI Computer Vision platforms have to be monitored using platform
+devices like sensors, fan controller, IO expander etc. Some of these devices
+are memory mapped and some are i2c based. Either of these devices are not
+directly accessible to the host.
+
+The host here refers to the server to which the vision accelerators are
+connected over PCIe Interface. The Host needs to do a consolidated action based
+on the parameters of platform devices. In general, most of the standard devices
+(includes sensors, fan controller, IO expander etc) are I2C/SMBus based and are
+used to provide the status of the accelerator. Standard drivers for these
+devices are available based on i2c/smbus APIs.
+
+Instead of changing the sensor drivers to adapt to PCIe interface, a generic
+i2c adapter "xlink-smbus" which underneath uses xlink as physical medium is
+used. With xlink-smbus, the drivers for the platform devices doesn't need to
+undergo any interface change.
+
+High-level architecture
+=======================
+
+Accessing Onchip devices::
+
+ ------------------- -------------------
+ | Remote Host | | Local Host |
+ | IA CPU | | Vision platforms|
+ ------------------- -------------------
+ | Onchip | | i2c slave | ==> Access the device
+ | sensor driver | | handler | ==> which is mmio based
+ ------------------- -------------------
+ |Intel XLINK_SMBUS| |Intel XLINK_SMBUS|
+ | adpater | | adapter |
+ | (Master) | | (I2C_SLAVE) |
+ ------------------- -------------------
+ | XLINK | <==========> | XLINK |
+ ------------------- PCIE -------------------
+
+Accessing Onboard devices::
+
+ ------------------- ----------------------
+ | Remote Host | | Local Host |
+ | IA CPU | | Vision platforms |
+ ------------------- ----------------------
+ | On board | | i2c smbus | ==> Access the device
+ | sensor driver | | xfer [synopsys] | ==> which is on i2c bus
+ ------------------- ----------------------
+ |Intel XLINK_SMBUS| | Intel XLINK_SMBUS |
+ | adpater | | adapter |
+ | (Master) | |(SMBUS_PROXY Master)|
+ ------------------- ----------------------
+ | XLINK | <==========> | XLINK |
+ ------------------- PCIE ----------------------
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index aed3ef61897c..f6229dd8ba9e 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -486,4 +486,5 @@ source "drivers/misc/xlink-ipc/Kconfig"
source "drivers/misc/xlink-core/Kconfig"
source "drivers/misc/vpumgr/Kconfig"
source "drivers/misc/intel_tsens/Kconfig"
+source "drivers/misc/xlink-smbus/Kconfig"
endmenu
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index c08502b22778..0ed8a62cbb20 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -62,3 +62,4 @@ obj-$(CONFIG_XLINK_IPC) += xlink-ipc/
obj-$(CONFIG_XLINK_CORE) += xlink-core/
obj-$(CONFIG_VPUMGR) += vpumgr/
obj-y += intel_tsens/
+obj-$(CONFIG_XLINK_SMBUS) += xlink-smbus/
diff --git a/drivers/misc/xlink-smbus/Kconfig b/drivers/misc/xlink-smbus/Kconfig
new file mode 100644
index 000000000000..e6cdf8b9a096
--- /dev/null
+++ b/drivers/misc/xlink-smbus/Kconfig
@@ -0,0 +1,26 @@
+# Copyright (C) 2020 Intel Corporation
+# SPDX-License-Identifier: GPL-2.0-only
+
+config XLINK_SMBUS
+ tristate "Enable smbus interface over Xlink PCIe"
+ depends on XLINK_CORE
+ depends on HDDL_DEVICE_CLIENT || HDDL_DEVICE_SERVER
+ help
+ Enable xlink-pcie as i2c adapter both slave and master. The server
+ (Remote Host) will use this interface to get sensor data from the soc
+ (vision accelerator - Local Host) which is connected over PCIe.
+ This driver is loaded on both Remote Host and Local Host.
+ Select M to compile the driver as a module, name is xlink-smbus.
+ If unsure, select N.
+
+
+config XLINK_SMBUS_PROXY
+ tristate "Enable SMBUS adapter as proxy for I2C controller"
+ depends on XLINK_CORE
+ depends on XLINK_SMBUS
+ help
+ Enable this config when SMBUS adapter is acting as proxy for
+ another I2C controller.
+ Select M or Y if building for Intel Vision Processing Unit (VPU)
+ Local Host core.
+ Select N, if building for a Remote Host kernel.
diff --git a/drivers/misc/xlink-smbus/Makefile b/drivers/misc/xlink-smbus/Makefile
new file mode 100644
index 000000000000..27369dfa488c
--- /dev/null
+++ b/drivers/misc/xlink-smbus/Makefile
@@ -0,0 +1,5 @@
+# Copyright (C) 2020 Intel Corporation
+# SPDX-License-Identifier: GPL-2.0-only
+# Makefile for Xlink SMBus
+#
+obj-$(CONFIG_XLINK_SMBUS) += xlink-smbus.o
diff --git a/drivers/misc/xlink-smbus/xlink-smbus.c b/drivers/misc/xlink-smbus/xlink-smbus.c
new file mode 100644
index 000000000000..fc652e6c96bb
--- /dev/null
+++ b/drivers/misc/xlink-smbus/xlink-smbus.c
@@ -0,0 +1,467 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel Xlink SMBus Driver
+ *
+ * Copyright (C) 2020 Intel Corporation
+ */
+
+#include <linux/hddl_device.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/stddef.h>
+#include <linux/time.h>
+#include <linux/xlink.h>
+
+struct xlink_msg {
+ u16 addr;
+ u16 flags;
+ u8 read_write;
+ u8 command;
+ u16 padding;
+ u32 protocol;
+ union i2c_smbus_data data;
+ s32 status;
+ struct list_head node;
+};
+
+struct xlink_adapter_data {
+ struct xlink_handle *xhandle;
+ struct completion work;
+ struct task_struct *task_recv;
+ struct i2c_client *slave;
+ struct list_head head;
+ struct i2c_adapter *adap;
+ u32 channel;
+};
+
+#if defined(CONFIG_XLINK_SMBUS_PROXY)
+/*
+ * PROXY the commands using existing adapter
+ * I2C2 is fixed for Keem Bay, it has all sensors connected
+ */
+#define proxy_i2c_adapter_info() i2c_get_adapter(2)
+#else
+/*
+ * This is an adapter by itself
+ * It doesn't proxy transfer on another adapter
+ */
+#define proxy_i2c_adapter_info() ((void *)0)
+#endif
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+/*
+ * The complete slave protocol is implemented in one shot here as
+ * the whole chunk of data is transferred or received via xlink,
+ * not byte-by-byte
+ * Refer https://lwn.net/Articles/640346/ for protocol
+ */
+static s32 handle_slave_mode(struct i2c_client *slave, struct xlink_msg *msg)
+{
+ struct device *dev = &slave->dev;
+ u8 temp;
+
+ /* Send the command as first write */
+ i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, NULL);
+ i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &msg->command);
+
+ /* Now handle specifics to read/write */
+ if (msg->read_write == I2C_SMBUS_WRITE) {
+ if (msg->protocol == I2C_SMBUS_BYTE_DATA) {
+ i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED,
+ &msg->data.byte);
+ } else if (msg->protocol == I2C_SMBUS_WORD_DATA) {
+ temp = msg->data.word & 0xFF;
+ i2c_slave_event(slave,
+ I2C_SLAVE_WRITE_RECEIVED,
+ &temp);
+ temp = (msg->data.word >> 8) & 0xFF;
+ i2c_slave_event(slave,
+ I2C_SLAVE_WRITE_RECEIVED,
+ &temp);
+ } else if (msg->protocol == I2C_SMBUS_BLOCK_DATA) {
+ int i;
+
+ if (msg->data.block[0] > I2C_SMBUS_BLOCK_MAX)
+ return -EPROTO;
+
+ for (i = 1; (i < msg->data.block[0] ||
+ i <= I2C_SMBUS_BLOCK_MAX); ++i) {
+ i2c_slave_event(slave,
+ I2C_SLAVE_WRITE_RECEIVED,
+ &msg->data.block[i]);
+ }
+ } else {
+ dev_err(dev,
+ "unknown protocol (%d) received in %s\n",
+ msg->protocol,
+ __func__
+ );
+ return -EOPNOTSUPP;
+ }
+ } else {
+ if (msg->protocol == I2C_SMBUS_BYTE_DATA) {
+ i2c_slave_event(slave,
+ I2C_SLAVE_READ_REQUESTED,
+ &msg->data.byte);
+ } else if (msg->protocol == I2C_SMBUS_WORD_DATA) {
+ i2c_slave_event(slave,
+ I2C_SLAVE_READ_REQUESTED,
+ &temp);
+ msg->data.word = temp << 8;
+ i2c_slave_event(slave,
+ I2C_SLAVE_READ_REQUESTED,
+ &temp);
+ msg->data.word |= temp;
+ } else if (msg->protocol == I2C_SMBUS_BLOCK_DATA) {
+ int i;
+
+ if (msg->data.block[0] > I2C_SMBUS_BLOCK_MAX)
+ return -EPROTO;
+
+ for (i = 1; (i < msg->data.block[0] ||
+ i <= I2C_SMBUS_BLOCK_MAX); ++i) {
+ i2c_slave_event(slave,
+ I2C_SLAVE_READ_REQUESTED,
+ &msg->data.block[i]);
+ }
+ } else {
+ dev_err(dev,
+ "unknown protocol (%d) received in %s\n",
+ msg->protocol,
+ __func__);
+ return -EOPNOTSUPP;
+ }
+ i2c_slave_event(slave, I2C_SLAVE_READ_PROCESSED, &temp);
+ }
+ i2c_slave_event(slave, I2C_SLAVE_STOP, NULL);
+ return 0;
+}
+#endif /* CONFIG_I2C_SLAVE */
+
+static s32 xlink_smbus_xfer(struct i2c_adapter *adap, u16 addr,
+ unsigned short flags, char read_write,
+ u8 command, int protocol,
+ union i2c_smbus_data *data)
+{
+ struct xlink_adapter_data *adapt_data = NULL;
+ struct device *dev = NULL;
+ struct xlink_msg tx_msg, *rx_msg;
+ enum xlink_error xerr;
+ s32 rc = 0;
+
+ if (!adap)
+ return -ENODEV;
+ adapt_data = i2c_get_adapdata(adap);
+ dev = &adapt_data->adap->dev;
+
+ if (!data)
+ return -EINVAL;
+
+ tx_msg.addr = addr;
+ tx_msg.flags = flags;
+ tx_msg.read_write = read_write;
+ tx_msg.command = command;
+ tx_msg.protocol = protocol;
+ tx_msg.data = *data;
+ tx_msg.status = 0;
+
+ xerr = xlink_write_data(adapt_data->xhandle, adapt_data->channel,
+ (u8 *)&tx_msg,
+ sizeof(struct xlink_msg));
+
+ if (xerr != X_LINK_SUCCESS) {
+ dev_err_ratelimited(dev,
+ "xlink_write_data failed (%d) dropping packet.\n",
+ xerr);
+ return -EIO;
+ }
+
+ /*
+ * wait for getting the response from the peer host device
+ * message is received by xlinki2c_receive_thread
+ * and notified here through completion trigger
+ */
+ if (wait_for_completion_interruptible_timeout(&adapt_data->work,
+ 4 * HZ) > 0) {
+ rx_msg = list_first_entry(&adapt_data->head,
+ struct xlink_msg,
+ node);
+ list_del(&rx_msg->node);
+
+ /* Update the data and status from the xlink message received */
+ *data = rx_msg->data;
+ rc = rx_msg->status;
+
+ /* free the response received from Proxy */
+ kfree(rx_msg);
+ } else {
+ WARN_ONCE(1, "VPU not responding");
+ rc = -ETIMEDOUT;
+ }
+
+ return rc;
+}
+
+static int xlinki2c_receive_thread(void *param)
+{
+ struct xlink_adapter_data *adapt_data = param;
+ struct device *dev = &adapt_data->adap->dev;
+ struct i2c_adapter *adap;
+ enum xlink_error xerr;
+ struct xlink_msg *msg;
+ u32 size;
+
+ while (!kthread_should_stop()) {
+ /* msg will be freed in this context or other */
+ msg = kzalloc(sizeof(*msg), GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ /* Wait to receive xlink message from the peer device */
+ xerr = xlink_read_data_to_buffer(adapt_data->xhandle,
+ adapt_data->channel,
+ (uint8_t *)msg, &size);
+ if (xerr != X_LINK_SUCCESS) {
+ if (xerr != X_LINK_TIMEOUT) {
+ dev_warn_ratelimited(dev,
+ "[%d] Error (%d) dropping packet.\n",
+ adapt_data->adap->nr, xerr);
+ }
+ kfree(msg);
+ continue;
+ }
+ xlink_release_data(adapt_data->xhandle, adapt_data->channel,
+ NULL);
+ adap = proxy_i2c_adapter_info();
+
+ if (adap) {
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ if (adapt_data->slave) {
+ msg->status = handle_slave_mode
+ (adapt_data->slave, msg);
+ goto send_resp;
+ }
+#endif
+ /*
+ * This is a proxy for an existing adapter.
+ * call the local adapter to receive the data
+ * from the hardware.
+ */
+ msg->status = i2c_smbus_xfer(adap,
+ msg->addr,
+ msg->flags,
+ msg->read_write,
+ msg->command,
+ msg->protocol,
+ &msg->data);
+
+ /*
+ * Send back the complete message that
+ * carries status, back to sender which is
+ * waiting on xlinki2c_receive_thread
+ */
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+send_resp:
+#endif
+ xlink_write_data(adapt_data->xhandle,
+ adapt_data->channel, (u8 *)msg,
+ sizeof(struct xlink_msg));
+ kfree(msg);
+ } else {
+ /*
+ * This is an adapter on its own.
+ * Receives the status and data over xlink (msg).
+ * Indicate the data received to the component
+ * which is waiting in xlink_smbus_xfer
+ */
+ list_add_tail(&msg->node, &adapt_data->head);
+ complete(&adapt_data->work);
+ }
+ } /* thread loop */
+ dev_dbg(dev, "[%d] %s stopped\n", adapt_data->adap->nr, __func__);
+
+ return 0;
+}
+
+static inline u32 xlink_smbus_func(struct i2c_adapter *adapter)
+{
+ u32 func = I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
+ I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
+ I2C_FUNC_SMBUS_BLOCK_DATA;
+
+ return func;
+}
+
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+
+/*
+ * This will be called when slave client driver
+ * register itself to an adapter
+ */
+static int xlink_smbus_reg_slave(struct i2c_client *slave)
+{
+ struct xlink_adapter_data *adapt_data =
+ i2c_get_adapdata(slave->adapter);
+
+ adapt_data->slave = slave;
+
+ return 0;
+}
+
+static int xlink_smbus_unreg_slave(struct i2c_client *slave)
+{
+ struct xlink_adapter_data *adapt_data =
+ i2c_get_adapdata(slave->adapter);
+
+ adapt_data->slave = NULL;
+
+ return 0;
+}
+#endif
+
+static struct i2c_algorithm xlink_algorithm = {
+ .smbus_xfer = xlink_smbus_xfer,
+ .functionality = xlink_smbus_func,
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ .reg_slave = xlink_smbus_reg_slave,
+ .unreg_slave = xlink_smbus_unreg_slave,
+#endif
+};
+
+static int xlink_i2c_probe(struct platform_device *pdev)
+{
+ struct intel_hddl_clients *c = pdev->dev.platform_data;
+ struct xlink_handle *devhandle = &c->xlink_dev;
+ struct xlink_adapter_data *adapt_data;
+ struct device *dev = &pdev->dev;
+ struct i2c_adapter *adap;
+ u32 rc;
+
+ dev_dbg(dev, "Registering xlink SMBus adapter...\n");
+
+ adap = kzalloc(sizeof(*adap), GFP_KERNEL);
+ if (!adap)
+ return -ENOMEM;
+
+ c->adap[pdev->id & 0x3] = adap;
+ memset(adap, 0, sizeof(struct i2c_adapter));
+ adap->owner = THIS_MODULE;
+ adap->algo = &xlink_algorithm;
+ strcpy(adap->name, "xlink adapter");
+ platform_set_drvdata(pdev, adap);
+
+ adapt_data = kzalloc(sizeof(*adapt_data), GFP_KERNEL);
+ if (!adapt_data) {
+ kfree(adap);
+ return -ENOMEM;
+ }
+
+ init_completion(&adapt_data->work);
+
+ INIT_LIST_HEAD(&adapt_data->head);
+ adapt_data->channel = c->xlink_i2c_ch[pdev->id & 0x3];
+ adapt_data->xhandle = devhandle;
+ adapt_data->adap = adap;
+
+ rc = xlink_open_channel(devhandle,
+ adapt_data->channel,
+ RXB_TXB, /* mode */
+ 64 * 1024,
+ 100); /* timeout */
+ if (rc != X_LINK_SUCCESS) {
+ dev_err(dev, "xlink_open_channel failed[%d][%d][%p]\n", rc,
+ adapt_data->channel,
+ adapt_data->xhandle);
+ goto err_kfree;
+ }
+
+ i2c_set_adapdata(adap, adapt_data);
+
+ rc = i2c_add_adapter(adap);
+ if (rc)
+ goto err_exit;
+
+ /* Create receiver thread */
+ adapt_data->task_recv = kthread_run(xlinki2c_receive_thread,
+ adapt_data,
+ "xlinki2c_receive_thread");
+ if (!adapt_data->task_recv) {
+ dev_err(dev, "%s Thread creation failed", __func__);
+ i2c_del_adapter(adapt_data->adap);
+ goto err_exit;
+ }
+ return 0;
+
+err_exit:
+ xlink_close_channel(adapt_data->xhandle, adapt_data->channel);
+err_kfree:
+ kfree(adap);
+ kfree(adapt_data);
+ return rc;
+}
+
+static int xlink_i2c_remove(struct platform_device *pdev)
+{
+ struct i2c_adapter *adap = platform_get_drvdata(pdev);
+ struct xlink_adapter_data *adapt_data = i2c_get_adapdata(adap);
+
+ kthread_stop(adapt_data->task_recv);
+
+ dev_info(&adap->dev, "Delete the adapter[%d]\n", adap->nr);
+ /* Close the channel and disconnect */
+ xlink_close_channel(adapt_data->xhandle, adapt_data->channel);
+ /* This will block the dynamic registration */
+ i2c_del_adapter(adapt_data->adap);
+ kfree(adapt_data);
+
+ return 0;
+}
+
+static struct platform_driver xlink_i2c_driver = {
+ .probe = xlink_i2c_probe,
+ .remove = xlink_i2c_remove,
+ .driver = {
+ .name = "i2c_xlink"
+ }
+};
+
+/* Define the xlink debug device structures to be used with dev_dbg() et al */
+
+static struct device_driver dbg_name = {
+ .name = "xlink_i2c_dbg"
+};
+
+static struct device dbg_subname = {
+ .init_name = "xlink_i2c_dbg",
+ .driver = &dbg_name
+};
+
+static struct device *dbgxi2c = &dbg_subname;
+
+static void __exit xlink_adapter_exit(void)
+{
+ dev_dbg(dbgxi2c, "Unloading XLink I2C module...\n");
+ platform_driver_unregister(&xlink_i2c_driver);
+}
+
+static int __init xlink_adapter_init(void)
+{
+ dev_dbg(dbgxi2c, "Loading XLink I2C module...\n");
+ platform_driver_register(&xlink_i2c_driver);
+ return 0;
+}
+
+module_init(xlink_adapter_init);
+module_exit(xlink_adapter_exit);
+
+MODULE_AUTHOR("Raja Subramanian, Lakshmi Bai <lakshmi.bai.raja.subramanian@intel.com>");
+MODULE_AUTHOR("Thalaiappan, Rathina <rathina.thalaiappan@intel.com>");
+MODULE_AUTHOR("Karanth, Ramya P <ramya.p.karanth@intel.com>");
+MODULE_DESCRIPTION("xlink i2c adapter");
+MODULE_LICENSE("GPL");
--
2.17.1