1 files changed, 315 insertions, 38 deletions

diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
index 5a1dd7f13bac..0316b347f9e7 100644
--- a/drivers/i2c/i2c-smbus.c
+++ b/drivers/i2c/i2c-smbus.c
@@ -1,27 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * i2c-smbus.c - SMBus extensions to the I2C protocol
  *
  * Copyright (C) 2008 David Brownell
- * Copyright (C) 2010 Jean Delvare <jdelvare@suse.de>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * 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.
+ * Copyright (C) 2010-2019 Jean Delvare <jdelvare@suse.de>
  */
 
 #include <linux/device.h>
+#include <linux/dmi.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/i2c-smbus.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/of_irq.h>
+#include <linux/property.h>
 #include <linux/slab.h>
 #include <linux/workqueue.h>
 
@@ -42,6 +35,7 @@ static int smbus_do_alert(struct device *dev, void *addrp)
 	struct i2c_client *client = i2c_verify_client(dev);
 	struct alert_data *data = addrp;
 	struct i2c_driver *driver;
+	int ret;
 
 	if (!client || client->addr != data->addr)
 		return 0;
@@ -55,16 +49,47 @@ static int smbus_do_alert(struct device *dev, void *addrp)
 	device_lock(dev);
 	if (client->dev.driver) {
 		driver = to_i2c_driver(client->dev.driver);
-		if (driver->alert)
+		if (driver->alert) {
+			/* Stop iterating after we find the device */
 			driver->alert(client, data->type, data->data);
-		else
+			ret = -EBUSY;
+		} else {
 			dev_warn(&client->dev, "no driver alert()!\n");
-	} else
+			ret = -EOPNOTSUPP;
+		}
+	} else {
 		dev_dbg(&client->dev, "alert with no driver\n");
+		ret = -ENODEV;
+	}
+	device_unlock(dev);
+
+	return ret;
+}
+
+/* Same as above, but call back all drivers with alert handler */
+
+static int smbus_do_alert_force(struct device *dev, void *addrp)
+{
+	struct i2c_client *client = i2c_verify_client(dev);
+	struct alert_data *data = addrp;
+	struct i2c_driver *driver;
+
+	if (!client || (client->flags & I2C_CLIENT_TEN))
+		return 0;
+
+	/*
+	 * Drivers should either disable alerts, or provide at least
+	 * a minimal handler. Lock so the driver won't change.
+	 */
+	device_lock(dev);
+	if (client->dev.driver) {
+		driver = to_i2c_driver(client->dev.driver);
+		if (driver->alert)
+			driver->alert(client, data->type, data->data);
+	}
 	device_unlock(dev);
 
-	/* Stop iterating after we find the device */
-	return -EBUSY;
+	return 0;
 }
 
 /*
@@ -75,7 +100,7 @@ static irqreturn_t smbus_alert(int irq, void *d)
 {
 	struct i2c_smbus_alert *alert = d;
 	struct i2c_client *ara;
-	unsigned short prev_addr = 0;	/* Not a valid address */
+	unsigned short prev_addr = I2C_CLIENT_END; /* Not a valid address */
 
 	ara = alert->ara;
 
@@ -99,17 +124,28 @@ static irqreturn_t smbus_alert(int irq, void *d)
 		data.addr = status >> 1;
 		data.type = I2C_PROTOCOL_SMBUS_ALERT;
 
-		if (data.addr == prev_addr) {
-			dev_warn(&ara->dev, "Duplicate SMBALERT# from dev "
-				"0x%02x, skipping\n", data.addr);
-			break;
-		}
 		dev_dbg(&ara->dev, "SMBALERT# from dev 0x%02x, flag %d\n",
 			data.addr, data.data);
 
 		/* Notify driver for the device which issued the alert */
-		device_for_each_child(&ara->adapter->dev, &data,
-				      smbus_do_alert);
+		status = device_for_each_child(&ara->adapter->dev, &data,
+					       smbus_do_alert);
+		/*
+		 * If we read the same address more than once, and the alert
+		 * was not handled by a driver, it won't do any good to repeat
+		 * the loop because it will never terminate. Try again, this
+		 * time calling the alert handlers of all devices connected to
+		 * the bus, and abort the loop afterwards. If this helps, we
+		 * are all set. If it doesn't, there is nothing else we can do,
+		 * so we might as well abort the loop.
+		 * Note: This assumes that a driver with alert handler handles
+		 * the alert properly and clears it if necessary.
+		 */
+		if (data.addr == prev_addr && status != -EBUSY) {
+			device_for_each_child(&ara->adapter->dev, &data,
+					      smbus_do_alert_force);
+			break;
+		}
 		prev_addr = data.addr;
 	}
 
@@ -127,12 +163,13 @@ static void smbalert_work(struct work_struct *work)
 }
 
 /* Setup SMBALERT# infrastructure */
-static int smbalert_probe(struct i2c_client *ara,
-			  const struct i2c_device_id *id)
+static int smbalert_probe(struct i2c_client *ara)
 {
 	struct i2c_smbus_alert_setup *setup = dev_get_platdata(&ara->dev);
 	struct i2c_smbus_alert *alert;
 	struct i2c_adapter *adapter = ara->adapter;
+	unsigned long irqflags = IRQF_SHARED | IRQF_ONESHOT;
+	struct gpio_desc *gpiod;
 	int res, irq;
 
 	alert = devm_kzalloc(&ara->dev, sizeof(struct i2c_smbus_alert),
@@ -143,19 +180,27 @@ static int smbalert_probe(struct i2c_client *ara,
 	if (setup) {
 		irq = setup->irq;
 	} else {
-		irq = of_irq_get_byname(adapter->dev.of_node, "smbus_alert");
-		if (irq <= 0)
-			return irq;
+		irq = fwnode_irq_get_byname(dev_fwnode(adapter->dev.parent),
+					    "smbus_alert");
+		if (irq <= 0) {
+			gpiod = devm_gpiod_get(adapter->dev.parent, "smbalert", GPIOD_IN);
+			if (IS_ERR(gpiod))
+				return PTR_ERR(gpiod);
+
+			irq = gpiod_to_irq(gpiod);
+			if (irq <= 0)
+				return irq;
+
+			irqflags |= IRQF_TRIGGER_FALLING;
+		}
 	}
 
 	INIT_WORK(&alert->alert, smbalert_work);
 	alert->ara = ara;
 
 	if (irq > 0) {
-		res = devm_request_threaded_irq(&ara->dev, irq,
-						NULL, smbus_alert,
-						IRQF_SHARED | IRQF_ONESHOT,
-						"smbus_alert", alert);
+		res = devm_request_threaded_irq(&ara->dev, irq, NULL, smbus_alert,
+						irqflags, "smbus_alert", alert);
 		if (res)
 			return res;
 	}
@@ -167,16 +212,15 @@ static int smbalert_probe(struct i2c_client *ara,
 }
 
 /* IRQ and memory resources are managed so they are freed automatically */
-static int smbalert_remove(struct i2c_client *ara)
+static void smbalert_remove(struct i2c_client *ara)
 {
 	struct i2c_smbus_alert *alert = i2c_get_clientdata(ara);
 
 	cancel_work_sync(&alert->alert);
-	return 0;
 }
 
 static const struct i2c_device_id smbalert_ids[] = {
-	{ "smbus_alert", 0 },
+	{ "smbus_alert" },
 	{ /* LIST END */ }
 };
 MODULE_DEVICE_TABLE(i2c, smbalert_ids);
@@ -200,7 +244,7 @@ static struct i2c_driver smbalert_driver = {
  * corresponding I2C device driver's alert function.
  *
  * It is assumed that ara is a valid i2c client previously returned by
- * i2c_setup_smbus_alert().
+ * i2c_new_smbus_alert_device().
  */
 int i2c_handle_smbus_alert(struct i2c_client *ara)
 {
@@ -212,6 +256,239 @@ EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert);
 
 module_i2c_driver(smbalert_driver);
 
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+#define SMBUS_HOST_NOTIFY_LEN	3
+struct i2c_slave_host_notify_status {
+	u8 index;
+	u8 addr;
+};
+
+static int i2c_slave_host_notify_cb(struct i2c_client *client,
+				    enum i2c_slave_event event, u8 *val)
+{
+	struct i2c_slave_host_notify_status *status = client->dev.platform_data;
+
+	switch (event) {
+	case I2C_SLAVE_WRITE_RECEIVED:
+		/* We only retrieve the first byte received (addr)
+		 * since there is currently no support to retrieve the data
+		 * parameter from the client.
+		 */
+		if (status->index == 0)
+			status->addr = *val;
+		if (status->index < U8_MAX)
+			status->index++;
+		break;
+	case I2C_SLAVE_STOP:
+		if (status->index == SMBUS_HOST_NOTIFY_LEN)
+			i2c_handle_smbus_host_notify(client->adapter,
+						     status->addr);
+		fallthrough;
+	case I2C_SLAVE_WRITE_REQUESTED:
+		status->index = 0;
+		break;
+	case I2C_SLAVE_READ_REQUESTED:
+	case I2C_SLAVE_READ_PROCESSED:
+		*val = 0xff;
+		break;
+	}
+
+	return 0;
+}
+
+/**
+ * i2c_new_slave_host_notify_device - get a client for SMBus host-notify support
+ * @adapter: the target adapter
+ * Context: can sleep
+ *
+ * Setup handling of the SMBus host-notify protocol on a given I2C bus segment.
+ *
+ * Handling is done by creating a device and its callback and handling data
+ * received via the SMBus host-notify address (0x8)
+ *
+ * This returns the client, which should be ultimately freed using
+ * i2c_free_slave_host_notify_device(); or an ERRPTR to indicate an error.
+ */
+struct i2c_client *i2c_new_slave_host_notify_device(struct i2c_adapter *adapter)
+{
+	struct i2c_board_info host_notify_board_info = {
+		I2C_BOARD_INFO("smbus_host_notify", 0x08),
+		.flags  = I2C_CLIENT_SLAVE,
+	};
+	struct i2c_slave_host_notify_status *status;
+	struct i2c_client *client;
+	int ret;
+
+	status = kzalloc(sizeof(struct i2c_slave_host_notify_status),
+			 GFP_KERNEL);
+	if (!status)
+		return ERR_PTR(-ENOMEM);
+
+	host_notify_board_info.platform_data = status;
+
+	client = i2c_new_client_device(adapter, &host_notify_board_info);
+	if (IS_ERR(client)) {
+		kfree(status);
+		return client;
+	}
+
+	ret = i2c_slave_register(client, i2c_slave_host_notify_cb);
+	if (ret) {
+		i2c_unregister_device(client);
+		kfree(status);
+		return ERR_PTR(ret);
+	}
+
+	return client;
+}
+EXPORT_SYMBOL_GPL(i2c_new_slave_host_notify_device);
+
+/**
+ * i2c_free_slave_host_notify_device - free the client for SMBus host-notify
+ * support
+ * @client: the client to free
+ * Context: can sleep
+ *
+ * Free the i2c_client allocated via i2c_new_slave_host_notify_device
+ */
+void i2c_free_slave_host_notify_device(struct i2c_client *client)
+{
+	if (IS_ERR_OR_NULL(client))
+		return;
+
+	i2c_slave_unregister(client);
+	kfree(client->dev.platform_data);
+	i2c_unregister_device(client);
+}
+EXPORT_SYMBOL_GPL(i2c_free_slave_host_notify_device);
+#endif
+
+/*
+ * SPD is not part of SMBus but we include it here for convenience as the
+ * target systems are the same.
+ * Restrictions to automatic SPD instantiation:
+ *  - Only works if all filled slots have the same memory type
+ *  - Only works for (LP)DDR memory types up to DDR5
+ *  - Only works on systems with 1 to 8 memory slots
+ */
+#if IS_ENABLED(CONFIG_DMI)
+static void i2c_register_spd(struct i2c_adapter *adap, bool write_disabled)
+{
+	int n, slot_count = 0, dimm_count = 0;
+	u16 handle;
+	u8 common_mem_type = 0x0, mem_type;
+	u64 mem_size;
+	bool instantiate = true;
+	const char *name;
+
+	while ((handle = dmi_memdev_handle(slot_count)) != 0xffff) {
+		slot_count++;
+
+		/* Skip empty slots */
+		mem_size = dmi_memdev_size(handle);
+		if (!mem_size)
+			continue;
+
+		/* Skip undefined memory type */
+		mem_type = dmi_memdev_type(handle);
+		if (mem_type <= 0x02)		/* Invalid, Other, Unknown */
+			continue;
+
+		if (!common_mem_type) {
+			/* First filled slot */
+			common_mem_type = mem_type;
+		} else {
+			/* Check that all filled slots have the same type */
+			if (mem_type != common_mem_type) {
+				dev_warn(&adap->dev,
+					 "Different memory types mixed, not instantiating SPD\n");
+				return;
+			}
+		}
+		dimm_count++;
+	}
+
+	/* No useful DMI data, bail out */
+	if (!dimm_count)
+		return;
+
+	/*
+	 * The max number of SPD EEPROMs that can be addressed per bus is 8.
+	 * If more slots are present either muxed or multiple busses are
+	 * necessary or the additional slots are ignored.
+	 */
+	slot_count = min(slot_count, 8);
+
+	/*
+	 * Memory types could be found at section 7.18.2 (Memory Device — Type), table 78
+	 * https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_3.6.0.pdf
+	 */
+	switch (common_mem_type) {
+	case 0x12:	/* DDR */
+	case 0x13:	/* DDR2 */
+	case 0x18:	/* DDR3 */
+	case 0x1B:	/* LPDDR */
+	case 0x1C:	/* LPDDR2 */
+	case 0x1D:	/* LPDDR3 */
+		name = "spd";
+		break;
+	case 0x1A:	/* DDR4 */
+	case 0x1E:	/* LPDDR4 */
+		name = "ee1004";
+		break;
+	case 0x22:	/* DDR5 */
+	case 0x23:	/* LPDDR5 */
+		name = "spd5118";
+		instantiate = !write_disabled;
+		break;
+	default:
+		dev_info(&adap->dev,
+			 "Memory type 0x%02x not supported yet, not instantiating SPD\n",
+			 common_mem_type);
+		return;
+	}
+
+	/*
+	 * We don't know in which slots the memory modules are. We could
+	 * try to guess from the slot names, but that would be rather complex
+	 * and unreliable, so better probe all possible addresses until we
+	 * have found all memory modules.
+	 */
+	for (n = 0; n < slot_count && dimm_count; n++) {
+		struct i2c_board_info info;
+		unsigned short addr_list[2];
+
+		memset(&info, 0, sizeof(struct i2c_board_info));
+		strscpy(info.type, name, I2C_NAME_SIZE);
+		addr_list[0] = 0x50 + n;
+		addr_list[1] = I2C_CLIENT_END;
+
+		if (!instantiate)
+			continue;
+
+		if (!IS_ERR(i2c_new_scanned_device(adap, &info, addr_list, NULL))) {
+			dev_info(&adap->dev,
+				 "Successfully instantiated SPD at 0x%hx\n",
+				 addr_list[0]);
+			dimm_count--;
+		}
+	}
+}
+
+void i2c_register_spd_write_disable(struct i2c_adapter *adap)
+{
+	i2c_register_spd(adap, true);
+}
+EXPORT_SYMBOL_GPL(i2c_register_spd_write_disable);
+
+void i2c_register_spd_write_enable(struct i2c_adapter *adap)
+{
+	i2c_register_spd(adap, false);
+}
+EXPORT_SYMBOL_GPL(i2c_register_spd_write_enable);
+
+#endif
+
 MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
 MODULE_DESCRIPTION("SMBus protocol extensions support");
 MODULE_LICENSE("GPL");