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