drivers/char/ipmi: Add powernv IPMI driver

This change adds an initial IPMI driver for powerpc OPAL firmware. The
interface is exposed entirely through firmware: we have two functions to
send and receive IPMI messages, and an interrupt notification from the
firmware to signify that a message is available.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>

drivers/char/ipmi/Kconfig

@@ -70,6 +70,12 @@ config IPMI_SSIF
 	 have a driver that must be accessed over an I2C bus instead of a
 	 standard interface.  This module requires I2C support.
 
+config IPMI_POWERNV
+       depends on PPC_POWERNV
+       tristate 'POWERNV (OPAL firmware) IPMI interface'
+       help
+         Provides a driver for OPAL firmware-based IPMI interfaces.
+
 config IPMI_WATCHDOG
        tristate 'IPMI Watchdog Timer'
        help

drivers/char/ipmi/Makefile

@@ -8,5 +8,6 @@ obj-$(CONFIG_IPMI_HANDLER) += ipmi_msghandler.o
 obj-$(CONFIG_IPMI_DEVICE_INTERFACE) += ipmi_devintf.o
 obj-$(CONFIG_IPMI_SI) += ipmi_si.o
 obj-$(CONFIG_IPMI_SSIF) += ipmi_ssif.o
+obj-$(CONFIG_IPMI_POWERNV) += ipmi_powernv.o
 obj-$(CONFIG_IPMI_WATCHDOG) += ipmi_watchdog.o
 obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o

drivers/char/ipmi/ipmi_powernv.c

@@ -0,0 +1,310 @@
+/*
+ * PowerNV OPAL IPMI driver
+ *
+ * Copyright 2014 IBM Corp.
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt)        "ipmi-powernv: " fmt
+
+#include <linux/ipmi_smi.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#include <asm/opal.h>
+
+
+struct ipmi_smi_powernv {
+	u64			interface_id;
+	struct ipmi_device_id	ipmi_id;
+	ipmi_smi_t		intf;
+	u64			event;
+	struct notifier_block	event_nb;
+
+	/**
+	 * We assume that there can only be one outstanding request, so
+	 * keep the pending message in cur_msg. We protect this from concurrent
+	 * updates through send & recv calls, (and consequently opal_msg, which
+	 * is in-use when cur_msg is set) with msg_lock
+	 */
+	spinlock_t		msg_lock;
+	struct ipmi_smi_msg	*cur_msg;
+	struct opal_ipmi_msg	*opal_msg;
+};
+
+static int ipmi_powernv_start_processing(void *send_info, ipmi_smi_t intf)
+{
+	struct ipmi_smi_powernv *smi = send_info;
+
+	smi->intf = intf;
+	return 0;
+}
+
+static void send_error_reply(struct ipmi_smi_powernv *smi,
+		struct ipmi_smi_msg *msg, u8 completion_code)
+{
+	msg->rsp[0] = msg->data[0] | 0x4;
+	msg->rsp[1] = msg->data[1];
+	msg->rsp[2] = completion_code;
+	msg->rsp_size = 3;
+	ipmi_smi_msg_received(smi->intf, msg);
+}
+
+static void ipmi_powernv_send(void *send_info, struct ipmi_smi_msg *msg)
+{
+	struct ipmi_smi_powernv *smi = send_info;
+	struct opal_ipmi_msg *opal_msg;
+	unsigned long flags;
+	int comp, rc;
+	size_t size;
+
+	/* ensure data_len will fit in the opal_ipmi_msg buffer... */
+	if (msg->data_size > IPMI_MAX_MSG_LENGTH) {
+		comp = IPMI_REQ_LEN_EXCEEDED_ERR;
+		goto err;
+	}
+
+	/* ... and that we at least have netfn and cmd bytes */
+	if (msg->data_size < 2) {
+		comp = IPMI_REQ_LEN_INVALID_ERR;
+		goto err;
+	}
+
+	spin_lock_irqsave(&smi->msg_lock, flags);
+
+	if (smi->cur_msg) {
+		comp = IPMI_NODE_BUSY_ERR;
+		goto err_unlock;
+	}
+
+	/* format our data for the OPAL API */
+	opal_msg = smi->opal_msg;
+	opal_msg->version = OPAL_IPMI_MSG_FORMAT_VERSION_1;
+	opal_msg->netfn = msg->data[0];
+	opal_msg->cmd = msg->data[1];
+	if (msg->data_size > 2)
+		memcpy(opal_msg->data, msg->data + 2, msg->data_size - 2);
+
+	/* data_size already includes the netfn and cmd bytes */
+	size = sizeof(*opal_msg) + msg->data_size - 2;
+
+	pr_devel("%s: opal_ipmi_send(0x%llx, %p, %ld)\n", __func__,
+			smi->interface_id, opal_msg, size);
+	rc = opal_ipmi_send(smi->interface_id, opal_msg, size);
+	pr_devel("%s:  -> %d\n", __func__, rc);
+
+	if (!rc) {
+		smi->cur_msg = msg;
+		spin_unlock_irqrestore(&smi->msg_lock, flags);
+		return;
+	}
+
+	comp = IPMI_ERR_UNSPECIFIED;
+err_unlock:
+	spin_unlock_irqrestore(&smi->msg_lock, flags);
+err:
+	send_error_reply(smi, msg, comp);
+}
+
+static int ipmi_powernv_recv(struct ipmi_smi_powernv *smi)
+{
+	struct opal_ipmi_msg *opal_msg;
+	struct ipmi_smi_msg *msg;
+	unsigned long flags;
+	uint64_t size;
+	int rc;
+
+	pr_devel("%s: opal_ipmi_recv(%llx, msg, sz)\n", __func__,
+			smi->interface_id);
+
+	spin_lock_irqsave(&smi->msg_lock, flags);
+
+	if (!smi->cur_msg) {
+		pr_warn("no current message?\n");
+		return 0;
+	}
+
+	msg = smi->cur_msg;
+	opal_msg = smi->opal_msg;
+
+	size = cpu_to_be64(sizeof(*opal_msg) + IPMI_MAX_MSG_LENGTH);
+
+	rc = opal_ipmi_recv(smi->interface_id,
+			opal_msg,
+			&size);
+	size = be64_to_cpu(size);
+	pr_devel("%s:   -> %d (size %lld)\n", __func__,
+			rc, rc == 0 ? size : 0);
+	if (rc) {
+		spin_unlock_irqrestore(&smi->msg_lock, flags);
+		ipmi_free_smi_msg(msg);
+		return 0;
+	}
+
+	if (size < sizeof(*opal_msg)) {
+		spin_unlock_irqrestore(&smi->msg_lock, flags);
+		pr_warn("unexpected IPMI message size %lld\n", size);
+		return 0;
+	}
+
+	if (opal_msg->version != OPAL_IPMI_MSG_FORMAT_VERSION_1) {
+		spin_unlock_irqrestore(&smi->msg_lock, flags);
+		pr_warn("unexpected IPMI message format (version %d)\n",
+				opal_msg->version);
+		return 0;
+	}
+
+	msg->rsp[0] = opal_msg->netfn;
+	msg->rsp[1] = opal_msg->cmd;
+	if (size > sizeof(*opal_msg))
+		memcpy(&msg->rsp[2], opal_msg->data, size - sizeof(*opal_msg));
+	msg->rsp_size = 2 + size - sizeof(*opal_msg);
+
+	smi->cur_msg = NULL;
+	spin_unlock_irqrestore(&smi->msg_lock, flags);
+	ipmi_smi_msg_received(smi->intf, msg);
+	return 0;
+}
+
+static void ipmi_powernv_request_events(void *send_info)
+{
+}
+
+static void ipmi_powernv_set_run_to_completion(void *send_info,
+		bool run_to_completion)
+{
+}
+
+static void ipmi_powernv_poll(void *send_info)
+{
+	struct ipmi_smi_powernv *smi = send_info;
+
+	ipmi_powernv_recv(smi);
+}
+
+static struct ipmi_smi_handlers ipmi_powernv_smi_handlers = {
+	.owner			= THIS_MODULE,
+	.start_processing	= ipmi_powernv_start_processing,
+	.sender			= ipmi_powernv_send,
+	.request_events		= ipmi_powernv_request_events,
+	.set_run_to_completion	= ipmi_powernv_set_run_to_completion,
+	.poll			= ipmi_powernv_poll,
+};
+
+static int ipmi_opal_event(struct notifier_block *nb,
+			  unsigned long events, void *change)
+{
+	struct ipmi_smi_powernv *smi = container_of(nb,
+					struct ipmi_smi_powernv, event_nb);
+
+	if (events & smi->event)
+		ipmi_powernv_recv(smi);
+	return 0;
+}
+
+static int ipmi_powernv_probe(struct platform_device *pdev)
+{
+	struct ipmi_smi_powernv *ipmi;
+	struct device *dev;
+	u32 prop;
+	int rc;
+
+	if (!pdev || !pdev->dev.of_node)
+		return -ENODEV;
+
+	dev = &pdev->dev;
+
+	ipmi = devm_kzalloc(dev, sizeof(*ipmi), GFP_KERNEL);
+	if (!ipmi)
+		return -ENOMEM;
+
+	spin_lock_init(&ipmi->msg_lock);
+
+	rc = of_property_read_u32(dev->of_node, "ibm,ipmi-interface-id",
+			&prop);
+	if (rc) {
+		dev_warn(dev, "No interface ID property\n");
+		goto err_free;
+	}
+	ipmi->interface_id = prop;
+
+	rc = of_property_read_u32(dev->of_node, "interrupts", &prop);
+	if (rc) {
+		dev_warn(dev, "No interrupts property\n");
+		goto err_free;
+	}
+
+	ipmi->event = 1ull << prop;
+	ipmi->event_nb.notifier_call = ipmi_opal_event;
+
+	rc = opal_notifier_register(&ipmi->event_nb);
+	if (rc) {
+		dev_warn(dev, "OPAL notifier registration failed (%d)\n", rc);
+		goto err_free;
+	}
+
+	ipmi->opal_msg = devm_kmalloc(dev,
+			sizeof(*ipmi->opal_msg) + IPMI_MAX_MSG_LENGTH,
+			GFP_KERNEL);
+	if (!ipmi->opal_msg) {
+		rc = -ENOMEM;
+		goto err_unregister;
+	}
+
+	/* todo: query actual ipmi_device_id */
+	rc = ipmi_register_smi(&ipmi_powernv_smi_handlers, ipmi,
+			&ipmi->ipmi_id, dev, 0);
+	if (rc) {
+		dev_warn(dev, "IPMI SMI registration failed (%d)\n", rc);
+		goto err_free_msg;
+	}
+
+	dev_set_drvdata(dev, ipmi);
+	return 0;
+
+err_free_msg:
+	devm_kfree(dev, ipmi->opal_msg);
+err_unregister:
+	opal_notifier_unregister(&ipmi->event_nb);
+err_free:
+	devm_kfree(dev, ipmi);
+	return rc;
+}
+
+static int ipmi_powernv_remove(struct platform_device *pdev)
+{
+	struct ipmi_smi_powernv *smi = dev_get_drvdata(&pdev->dev);
+
+	ipmi_unregister_smi(smi->intf);
+	opal_notifier_unregister(&smi->event_nb);
+	return 0;
+}
+
+static const struct of_device_id ipmi_powernv_match[] = {
+	{ .compatible = "ibm,opal-ipmi" },
+	{ },
+};
+
+
+static struct platform_driver powernv_ipmi_driver = {
+	.driver = {
+		.name		= "ipmi-powernv",
+		.owner		= THIS_MODULE,
+		.of_match_table	= ipmi_powernv_match,
+	},
+	.probe	= ipmi_powernv_probe,
+	.remove	= ipmi_powernv_remove,
+};
+
+
+module_platform_driver(powernv_ipmi_driver);
+
+MODULE_DEVICE_TABLE(of, ipmi_powernv_match);
+MODULE_DESCRIPTION("powernv IPMI driver");
+MODULE_AUTHOR("Jeremy Kerr <jk@ozlabs.org>");
+MODULE_LICENSE("GPL");