[v2] 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>

---
v2: Update for ipmi/for-next tree, add copyright header

---
 drivers/char/ipmi/Kconfig        |    6 
 drivers/char/ipmi/Makefile       |    1 
 drivers/char/ipmi/ipmi_powernv.c |  307 +++++++++++++++++++++++++++++++
 3 files changed, 314 insertions(+)

This looks good.  Can this go into the IPMI tree now, or does it need
work done in the PowerPC tree first?

Thanks,

-corey

On 11/12/2014 01:41 AM, Jeremy Kerr wrote:
> 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>
>
> ---
> v2: Update for ipmi/for-next tree, add copyright header
>
> ---
>  drivers/char/ipmi/Kconfig        |    6 
>  drivers/char/ipmi/Makefile       |    1 
>  drivers/char/ipmi/ipmi_powernv.c |  307 +++++++++++++++++++++++++++++++
>  3 files changed, 314 insertions(+)
>
> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig
> index c1fccf4..65fb008 100644
> --- a/drivers/char/ipmi/Kconfig
> +++ b/drivers/char/ipmi/Kconfig
> @@ -72,6 +72,12 @@ 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
> diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile
> index 115c08d..f3ffde1 100644
> --- a/drivers/char/ipmi/Makefile
> +++ b/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
> diff --git a/drivers/char/ipmi/ipmi_powernv.c b/drivers/char/ipmi/ipmi_powernv.c
> new file mode 100644
> index 0000000..50134ec
> --- /dev/null
> +++ b/drivers/char/ipmi/ipmi_powernv.c
> @@ -0,0 +1,307 @@
> +/*
> + * 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");

Hi Corey,

> This looks good.  Can this go into the IPMI tree now, or does it need
> work done in the PowerPC tree first?

The 1/2 patch is already in the powerpc tree - but to ensure that we hit
Linus' tree in the right order, Michael has suggested that you merge his
topic branch (which only has that one change):


https://git.kernel.org/cgit/linux/kernel/git/mpe/linux.git/log/?h=topic/opal-ipmi

- then apply the patch. This way, whichever tree Linus pulls first will
have the changes in the correct order.

Cheers,


Jeremy

On Thu, 2014-11-13 at 19:42 -0600, Corey Minyard wrote:
> This looks good.  Can this go into the IPMI tree now, or does it need
> work done in the PowerPC tree first?

You need to merge this first:

  https://git.kernel.org/cgit/linux/kernel/git/mpe/linux.git/log/?h=topic/opal-ipmi

ie.

  $ git fetch git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux.git topic/opal-ipmi
  $ git merge FETCH_HEAD

cheers