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authorJeremy Kerr <jk@ozlabs.org>2015-06-04 21:51:47 +0800
committerMichael Ellerman <mpe@ellerman.id.au>2015-06-05 08:32:21 +1000
commit0d7cd8550d30906c7461ced654306da30f1590e2 (patch)
tree006328e5709454b87b8834df552dc3dd229119f9 /arch/powerpc/platforms/powernv/opal-prd.c
parent594fcb9ec9e17215b4f98b5d40ba5e3af618ba82 (diff)
powerpc/powernv: Add opal-prd channel
This change adds a char device to access the "PRD" (processor runtime diagnostics) channel to OPAL firmware. Includes contributions from Vaidyanathan Srinivasan, Neelesh Gupta & Vishal Kulkarni. Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com> Signed-off-by: Jeremy Kerr <jk@ozlabs.org> Acked-by: Stewart Smith <stewart@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/platforms/powernv/opal-prd.c')
-rw-r--r--arch/powerpc/platforms/powernv/opal-prd.c444
1 files changed, 444 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/opal-prd.c b/arch/powerpc/platforms/powernv/opal-prd.c
new file mode 100644
index 000000000000..d9e72bde79f5
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-prd.c
@@ -0,0 +1,444 @@
+/*
+ * OPAL Runtime Diagnostics interface driver
+ * Supported on POWERNV platform
+ *
+ * Copyright IBM Corporation 2015
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "opal-prd: " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/miscdevice.h>
+#include <linux/fs.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/poll.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <asm/opal-prd.h>
+#include <asm/opal.h>
+#include <asm/io.h>
+#include <asm/uaccess.h>
+
+
+struct opal_prd_msg_queue_item {
+ struct opal_prd_msg_header msg;
+ struct list_head list;
+};
+
+static struct device_node *prd_node;
+static LIST_HEAD(opal_prd_msg_queue);
+static DEFINE_SPINLOCK(opal_prd_msg_queue_lock);
+static DECLARE_WAIT_QUEUE_HEAD(opal_prd_msg_wait);
+static atomic_t prd_usage;
+
+static bool opal_prd_range_is_valid(uint64_t addr, uint64_t size)
+{
+ struct device_node *parent, *node;
+ bool found;
+
+ if (addr + size < addr)
+ return false;
+
+ parent = of_find_node_by_path("/reserved-memory");
+ if (!parent)
+ return false;
+
+ found = false;
+
+ for_each_child_of_node(parent, node) {
+ uint64_t range_addr, range_size, range_end;
+ const __be32 *addrp;
+ const char *label;
+
+ addrp = of_get_address(node, 0, &range_size, NULL);
+
+ range_addr = of_read_number(addrp, 2);
+ range_end = range_addr + range_size;
+
+ label = of_get_property(node, "ibm,prd-label", NULL);
+
+ /* PRD ranges need a label */
+ if (!label)
+ continue;
+
+ if (range_end <= range_addr)
+ continue;
+
+ if (addr >= range_addr && addr + size <= range_end) {
+ found = true;
+ of_node_put(node);
+ break;
+ }
+ }
+
+ of_node_put(parent);
+ return found;
+}
+
+static int opal_prd_open(struct inode *inode, struct file *file)
+{
+ /*
+ * Prevent multiple (separate) processes from concurrent interactions
+ * with the FW PRD channel
+ */
+ if (atomic_xchg(&prd_usage, 1) == 1)
+ return -EBUSY;
+
+ return 0;
+}
+
+/*
+ * opal_prd_mmap - maps firmware-provided ranges into userspace
+ * @file: file structure for the device
+ * @vma: VMA to map the registers into
+ */
+
+static int opal_prd_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ size_t addr, size;
+ int rc;
+
+ pr_devel("opal_prd_mmap(0x%016lx, 0x%016lx, 0x%lx, 0x%lx)\n",
+ vma->vm_start, vma->vm_end, vma->vm_pgoff,
+ vma->vm_flags);
+
+ addr = vma->vm_pgoff << PAGE_SHIFT;
+ size = vma->vm_end - vma->vm_start;
+
+ /* ensure we're mapping within one of the allowable ranges */
+ if (!opal_prd_range_is_valid(addr, size))
+ return -EINVAL;
+
+ vma->vm_page_prot = __pgprot(pgprot_val(phys_mem_access_prot(file,
+ vma->vm_pgoff,
+ size, vma->vm_page_prot))
+ | _PAGE_SPECIAL);
+
+ rc = remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, size,
+ vma->vm_page_prot);
+
+ return rc;
+}
+
+static bool opal_msg_queue_empty(void)
+{
+ unsigned long flags;
+ bool ret;
+
+ spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
+ ret = list_empty(&opal_prd_msg_queue);
+ spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
+
+ return ret;
+}
+
+static unsigned int opal_prd_poll(struct file *file,
+ struct poll_table_struct *wait)
+{
+ poll_wait(file, &opal_prd_msg_wait, wait);
+
+ if (!opal_msg_queue_empty())
+ return POLLIN | POLLRDNORM;
+
+ return 0;
+}
+
+static ssize_t opal_prd_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct opal_prd_msg_queue_item *item;
+ unsigned long flags;
+ ssize_t size, err;
+ int rc;
+
+ /* we need at least a header's worth of data */
+ if (count < sizeof(item->msg))
+ return -EINVAL;
+
+ if (*ppos)
+ return -ESPIPE;
+
+ item = NULL;
+
+ for (;;) {
+
+ spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
+ if (!list_empty(&opal_prd_msg_queue)) {
+ item = list_first_entry(&opal_prd_msg_queue,
+ struct opal_prd_msg_queue_item, list);
+ list_del(&item->list);
+ }
+ spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
+
+ if (item)
+ break;
+
+ if (file->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
+ rc = wait_event_interruptible(opal_prd_msg_wait,
+ !opal_msg_queue_empty());
+ if (rc)
+ return -EINTR;
+ }
+
+ size = be16_to_cpu(item->msg.size);
+ if (size > count) {
+ err = -EINVAL;
+ goto err_requeue;
+ }
+
+ rc = copy_to_user(buf, &item->msg, size);
+ if (rc) {
+ err = -EFAULT;
+ goto err_requeue;
+ }
+
+ kfree(item);
+
+ return size;
+
+err_requeue:
+ /* eep! re-queue at the head of the list */
+ spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
+ list_add(&item->list, &opal_prd_msg_queue);
+ spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
+ return err;
+}
+
+static ssize_t opal_prd_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct opal_prd_msg_header hdr;
+ ssize_t size;
+ void *msg;
+ int rc;
+
+ size = sizeof(hdr);
+
+ if (count < size)
+ return -EINVAL;
+
+ /* grab the header */
+ rc = copy_from_user(&hdr, buf, sizeof(hdr));
+ if (rc)
+ return -EFAULT;
+
+ size = be16_to_cpu(hdr.size);
+
+ msg = kmalloc(size, GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ rc = copy_from_user(msg, buf, size);
+ if (rc) {
+ size = -EFAULT;
+ goto out_free;
+ }
+
+ rc = opal_prd_msg(msg);
+ if (rc) {
+ pr_warn("write: opal_prd_msg returned %d\n", rc);
+ size = -EIO;
+ }
+
+out_free:
+ kfree(msg);
+
+ return size;
+}
+
+static int opal_prd_release(struct inode *inode, struct file *file)
+{
+ struct opal_prd_msg_header msg;
+
+ msg.size = cpu_to_be16(sizeof(msg));
+ msg.type = OPAL_PRD_MSG_TYPE_FINI;
+
+ opal_prd_msg((struct opal_prd_msg *)&msg);
+
+ atomic_xchg(&prd_usage, 0);
+
+ return 0;
+}
+
+static long opal_prd_ioctl(struct file *file, unsigned int cmd,
+ unsigned long param)
+{
+ struct opal_prd_info info;
+ struct opal_prd_scom scom;
+ int rc = 0;
+
+ switch (cmd) {
+ case OPAL_PRD_GET_INFO:
+ memset(&info, 0, sizeof(info));
+ info.version = OPAL_PRD_KERNEL_VERSION;
+ rc = copy_to_user((void __user *)param, &info, sizeof(info));
+ if (rc)
+ return -EFAULT;
+ break;
+
+ case OPAL_PRD_SCOM_READ:
+ rc = copy_from_user(&scom, (void __user *)param, sizeof(scom));
+ if (rc)
+ return -EFAULT;
+
+ scom.rc = opal_xscom_read(scom.chip, scom.addr,
+ (__be64 *)&scom.data);
+ scom.data = be64_to_cpu(scom.data);
+ pr_devel("ioctl SCOM_READ: chip %llx addr %016llx data %016llx rc %lld\n",
+ scom.chip, scom.addr, scom.data, scom.rc);
+
+ rc = copy_to_user((void __user *)param, &scom, sizeof(scom));
+ if (rc)
+ return -EFAULT;
+ break;
+
+ case OPAL_PRD_SCOM_WRITE:
+ rc = copy_from_user(&scom, (void __user *)param, sizeof(scom));
+ if (rc)
+ return -EFAULT;
+
+ scom.rc = opal_xscom_write(scom.chip, scom.addr, scom.data);
+ pr_devel("ioctl SCOM_WRITE: chip %llx addr %016llx data %016llx rc %lld\n",
+ scom.chip, scom.addr, scom.data, scom.rc);
+
+ rc = copy_to_user((void __user *)param, &scom, sizeof(scom));
+ if (rc)
+ return -EFAULT;
+ break;
+
+ default:
+ rc = -EINVAL;
+ }
+
+ return rc;
+}
+
+static const struct file_operations opal_prd_fops = {
+ .open = opal_prd_open,
+ .mmap = opal_prd_mmap,
+ .poll = opal_prd_poll,
+ .read = opal_prd_read,
+ .write = opal_prd_write,
+ .unlocked_ioctl = opal_prd_ioctl,
+ .release = opal_prd_release,
+ .owner = THIS_MODULE,
+};
+
+static struct miscdevice opal_prd_dev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "opal-prd",
+ .fops = &opal_prd_fops,
+};
+
+/* opal interface */
+static int opal_prd_msg_notifier(struct notifier_block *nb,
+ unsigned long msg_type, void *_msg)
+{
+ struct opal_prd_msg_queue_item *item;
+ struct opal_prd_msg_header *hdr;
+ struct opal_msg *msg = _msg;
+ unsigned long flags;
+ int size;
+
+ if (msg_type != OPAL_MSG_PRD)
+ return 0;
+
+ /* Calculate total size of the item we need to store. The 'size' field
+ * in the header includes the header itself. */
+ hdr = (void *)msg->params;
+ size = (sizeof(*item) - sizeof(item->msg)) + be16_to_cpu(hdr->size);
+
+ item = kzalloc(size, GFP_ATOMIC);
+ if (!item)
+ return -ENOMEM;
+
+ memcpy(&item->msg, msg->params, size);
+
+ spin_lock_irqsave(&opal_prd_msg_queue_lock, flags);
+ list_add_tail(&item->list, &opal_prd_msg_queue);
+ spin_unlock_irqrestore(&opal_prd_msg_queue_lock, flags);
+
+ wake_up_interruptible(&opal_prd_msg_wait);
+
+ return 0;
+}
+
+static struct notifier_block opal_prd_event_nb = {
+ .notifier_call = opal_prd_msg_notifier,
+ .next = NULL,
+ .priority = 0,
+};
+
+static int opal_prd_probe(struct platform_device *pdev)
+{
+ int rc;
+
+ if (!pdev || !pdev->dev.of_node)
+ return -ENODEV;
+
+ /* We should only have one prd driver instance per machine; ensure
+ * that we only get a valid probe on a single OF node.
+ */
+ if (prd_node)
+ return -EBUSY;
+
+ prd_node = pdev->dev.of_node;
+
+ rc = opal_message_notifier_register(OPAL_MSG_PRD, &opal_prd_event_nb);
+ if (rc) {
+ pr_err("Couldn't register event notifier\n");
+ return rc;
+ }
+
+ rc = misc_register(&opal_prd_dev);
+ if (rc) {
+ pr_err("failed to register miscdev\n");
+ opal_message_notifier_unregister(OPAL_MSG_PRD,
+ &opal_prd_event_nb);
+ return rc;
+ }
+
+ return 0;
+}
+
+static int opal_prd_remove(struct platform_device *pdev)
+{
+ misc_deregister(&opal_prd_dev);
+ opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb);
+ return 0;
+}
+
+static const struct of_device_id opal_prd_match[] = {
+ { .compatible = "ibm,opal-prd" },
+ { },
+};
+
+static struct platform_driver opal_prd_driver = {
+ .driver = {
+ .name = "opal-prd",
+ .owner = THIS_MODULE,
+ .of_match_table = opal_prd_match,
+ },
+ .probe = opal_prd_probe,
+ .remove = opal_prd_remove,
+};
+
+module_platform_driver(opal_prd_driver);
+
+MODULE_DEVICE_TABLE(of, opal_prd_match);
+MODULE_DESCRIPTION("PowerNV OPAL runtime diagnostic driver");
+MODULE_LICENSE("GPL");

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