[POWERPC] Add PMI driver for cell blade

This adds driver code for the PMI device found in future IBM products.
PMI stands for "Platform Management Interrupt" and is a way to
communicate with the BMC (Baseboard Management Controller).
It provides bidirectional communication with a low latency.

Signed-off-by: Christian Krafft <krafft@de.ibm.com>
Acked-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Acked-by: Heiko J Schick <schickhj@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

4 files changed, 316 insertions, 0 deletions

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 340d9beab6d1..6dfbd52694ab 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -620,6 +620,15 @@ config RTAS_FLASH
         tristate "Firmware flash interface"
         depends on PPC64 && RTAS_PROC
 
+config PPC_PMI
+        tristate "Support for PMI"
+        depends PPC_IBM_CELL_BLADE
+        help
+          PMI (Platform Management Interrupt) is a way to
+          communicate with the BMC (Baseboard Mangement Controller).
+          It is used in some IBM Cell blades.
+        default m
+
 config MMIO_NVRAM
         bool
         default n
diff --git a/arch/powerpc/configs/cell_defconfig b/arch/powerpc/configs/cell_defconfig
index e956548da00c..24367319ce24 100644
--- a/arch/powerpc/configs/cell_defconfig
+++ b/arch/powerpc/configs/cell_defconfig
@@ -147,6 +147,7 @@ CONFIG_PPC_RTAS=y
 # CONFIG_RTAS_ERROR_LOGGING is not set
 CONFIG_RTAS_PROC=y
 CONFIG_RTAS_FLASH=y
+CONFIG_PPC_PMI=m
 CONFIG_MMIO_NVRAM=y
 # CONFIG_PPC_MPC106 is not set
 # CONFIG_PPC_970_NAP is not set
diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
index 85dcdf178415..26ca3ffbc1de 100644
--- a/arch/powerpc/sysdev/Makefile
+++ b/arch/powerpc/sysdev/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_PPC_INDIRECT_PCI)	+= indirect_pci.o
 obj-$(CONFIG_PPC_MPC106)        += grackle.o
 obj-$(CONFIG_PPC_DCR)           += dcr.o
 obj-$(CONFIG_PPC_DCR_NATIVE)    += dcr-low.o
+obj-$(CONFIG_PPC_PMI)           += pmi.o
 obj-$(CONFIG_U3_DART)           += dart_iommu.o
 obj-$(CONFIG_MMIO_NVRAM)        += mmio_nvram.o
 obj-$(CONFIG_FSL_SOC)           += fsl_soc.o
diff --git a/arch/powerpc/sysdev/pmi.c b/arch/powerpc/sysdev/pmi.c
new file mode 100644
index 000000000000..a5282011d39e
--- /dev/null
+++ b/arch/powerpc/sysdev/pmi.c
@@ -0,0 +1,305 @@
+/*
+ * pmi driver
+ *
+ * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
+ *
+ * PMI (Platform Management Interrupt) is a way to communicate
+ * with the BMC (Baseboard Management Controller) via interrupts.
+ * Unlike IPMI it is bidirectional and has a low latency.
+ *
+ * Author: Christian Krafft <krafft@de.ibm.com>
+ *
+ * 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, 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/completion.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+
+#include <asm/of_device.h>
+#include <asm/of_platform.h>
+#include <asm/io.h>
+#include <asm/pmi.h>
+
+
+struct pmi_data {
+        struct list_head        handler;
+        spinlock_t              handler_spinlock;
+        spinlock_t              pmi_spinlock;
+        struct mutex            msg_mutex;
+        pmi_message_t           msg;
+        struct completion       *completion;
+        struct of_device        *dev;
+        int                     irq;
+        u8 __iomem              *pmi_reg;
+        struct work_struct      work;
+};
+
+
+
+static void __iomem *of_iomap(struct device_node *np)
+{
+        struct resource res;
+
+        if (of_address_to_resource(np, 0, &res))
+                return NULL;
+
+        pr_debug("Resource start: 0x%lx\n", res.start);
+        pr_debug("Resource end: 0x%lx\n", res.end);
+
+        return ioremap(res.start, 1 + res.end - res.start);
+}
+
+
+static int pmi_irq_handler(int irq, void *dev_id)
+{
+        struct pmi_data *data;
+        u8 type;
+        int rc;
+
+        data = dev_id;
+
+        spin_lock(&data->pmi_spinlock);
+
+        type = ioread8(data->pmi_reg + PMI_READ_TYPE);
+        pr_debug("pmi: got message of type %d\n", type);
+
+        if (type & PMI_ACK && !data->completion) {
+                printk(KERN_WARNING "pmi: got unexpected ACK message.\n");
+                rc = -EIO;
+                goto unlock;
+        }
+
+        if (data->completion && !(type & PMI_ACK)) {
+                printk(KERN_WARNING "pmi: expected ACK, but got %d\n", type);
+                rc = -EIO;
+                goto unlock;
+        }
+
+        data->msg.type = type;
+        data->msg.data0 = ioread8(data->pmi_reg + PMI_READ_DATA0);
+        data->msg.data1 = ioread8(data->pmi_reg + PMI_READ_DATA1);
+        data->msg.data2 = ioread8(data->pmi_reg + PMI_READ_DATA2);
+        rc = 0;
+unlock:
+        spin_unlock(&data->pmi_spinlock);
+
+        if (rc == -EIO) {
+                rc = IRQ_HANDLED;
+                goto out;
+        }
+
+        if (data->msg.type & PMI_ACK) {
+                complete(data->completion);
+                rc = IRQ_HANDLED;
+                goto out;
+        }
+
+        schedule_work(&data->work);
+
+        rc = IRQ_HANDLED;
+out:
+        return rc;
+}
+
+
+static struct of_device_id pmi_match[] = {
+        { .type = "ibm,pmi", .name = "ibm,pmi" },
+        {},
+};
+
+MODULE_DEVICE_TABLE(of, pmi_match);
+
+static void pmi_notify_handlers(struct work_struct *work)
+{
+        struct pmi_data *data;
+        struct pmi_handler *handler;
+
+        data = container_of(work, struct pmi_data, work);
+
+        spin_lock(&data->handler_spinlock);
+        list_for_each_entry(handler, &data->handler, node) {
+                pr_debug(KERN_INFO "pmi: notifying handler %p\n", handler);
+                if (handler->type == data->msg.type)
+                        handler->handle_pmi_message(data->dev, data->msg);
+        }
+        spin_unlock(&data->handler_spinlock);
+}
+
+static int pmi_of_probe(struct of_device *dev,
+                        const struct of_device_id *match)
+{
+        struct device_node *np = dev->node;
+        struct pmi_data *data;
+        int rc;
+
+        data = kzalloc(sizeof(struct pmi_data), GFP_KERNEL);
+        if (!data) {
+                printk(KERN_ERR "pmi: could not allocate memory.\n");
+                rc = -ENOMEM;
+                goto out;
+        }
+
+        data->pmi_reg = of_iomap(np);
+        if (!data->pmi_reg) {
+                printk(KERN_ERR "pmi: invalid register address.\n");
+                rc = -EFAULT;
+                goto error_cleanup_data;
+        }
+
+        INIT_LIST_HEAD(&data->handler);
+
+        mutex_init(&data->msg_mutex);
+        spin_lock_init(&data->pmi_spinlock);
+        spin_lock_init(&data->handler_spinlock);
+
+        INIT_WORK(&data->work, pmi_notify_handlers);
+
+        dev->dev.driver_data = data;
+        data->dev = dev;
+
+        data->irq = irq_of_parse_and_map(np, 0);
+        if (data->irq == NO_IRQ) {
+                printk(KERN_ERR "pmi: invalid interrupt.\n");
+                rc = -EFAULT;
+                goto error_cleanup_iomap;
+        }
+
+        rc = request_irq(data->irq, pmi_irq_handler, 0, "pmi", data);
+        if (rc) {
+                printk(KERN_ERR "pmi: can't request IRQ %d: returned %d\n",
+                                data->irq, rc);
+                goto error_cleanup_iomap;
+        }
+
+        printk(KERN_INFO "pmi: found pmi device at addr %p.\n", data->pmi_reg);
+
+        goto out;
+
+error_cleanup_iomap:
+        iounmap(data->pmi_reg);
+
+error_cleanup_data:
+        kfree(data);
+
+out:
+        return rc;
+}
+
+static int pmi_of_remove(struct of_device *dev)
+{
+        struct pmi_data *data;
+        struct pmi_handler *handler, *tmp;
+
+        data = dev->dev.driver_data;
+
+        free_irq(data->irq, data);
+        iounmap(data->pmi_reg);
+
+        spin_lock(&data->handler_spinlock);
+
+        list_for_each_entry_safe(handler, tmp, &data->handler, node)
+                list_del(&handler->node);
+
+        spin_unlock(&data->handler_spinlock);
+
+        kfree(dev->dev.driver_data);
+
+        return 0;
+}
+
+static struct of_platform_driver pmi_of_platform_driver = {
+        .name           = "pmi",
+        .match_table    = pmi_match,
+        .probe          = pmi_of_probe,
+        .remove         = pmi_of_remove
+};
+
+static int __init pmi_module_init(void)
+{
+        return of_register_platform_driver(&pmi_of_platform_driver);
+}
+module_init(pmi_module_init);
+
+static void __exit pmi_module_exit(void)
+{
+        of_unregister_platform_driver(&pmi_of_platform_driver);
+}
+module_exit(pmi_module_exit);
+
+void pmi_send_message(struct of_device *device, pmi_message_t msg)
+{
+        struct pmi_data *data;
+        unsigned long flags;
+        DECLARE_COMPLETION_ONSTACK(completion);
+
+        data = device->dev.driver_data;
+
+        mutex_lock(&data->msg_mutex);
+
+        data->msg = msg;
+        pr_debug("pmi_send_message: msg is %08x\n", *(u32*)&msg);
+
+        data->completion = &completion;
+
+        spin_lock_irqsave(&data->pmi_spinlock, flags);
+        iowrite8(msg.data0, data->pmi_reg + PMI_WRITE_DATA0);
+        iowrite8(msg.data1, data->pmi_reg + PMI_WRITE_DATA1);
+        iowrite8(msg.data2, data->pmi_reg + PMI_WRITE_DATA2);
+        iowrite8(msg.type, data->pmi_reg + PMI_WRITE_TYPE);
+        spin_unlock_irqrestore(&data->pmi_spinlock, flags);
+
+        pr_debug("pmi_send_message: wait for completion\n");
+
+        wait_for_completion_interruptible_timeout(data->completion,
+                                                  PMI_TIMEOUT);
+
+        data->completion = NULL;
+
+        mutex_unlock(&data->msg_mutex);
+}
+EXPORT_SYMBOL_GPL(pmi_send_message);
+
+void pmi_register_handler(struct of_device *device,
+                          struct pmi_handler *handler)
+{
+        struct pmi_data *data;
+        data = device->dev.driver_data;
+
+        spin_lock(&data->handler_spinlock);
+        list_add_tail(&handler->node, &data->handler);
+        spin_unlock(&data->handler_spinlock);
+}
+EXPORT_SYMBOL_GPL(pmi_register_handler);
+
+void pmi_unregister_handler(struct of_device *device,
+                            struct pmi_handler *handler)
+{
+        struct pmi_data *data;
+
+        pr_debug("pmi: unregistering handler %p\n", handler);
+
+        data = device->dev.driver_data;
+
+        spin_lock(&data->handler_spinlock);
+        list_del(&handler->node);
+        spin_unlock(&data->handler_spinlock);
+}
+EXPORT_SYMBOL_GPL(pmi_unregister_handler);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>");
+MODULE_DESCRIPTION("IBM Platform Management Interrupt driver");