1 files changed, 508 insertions, 0 deletions

diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
new file mode 100644
index 000000000000..847b7e646a7e
--- /dev/null
+++ b/drivers/misc/cxl/file.c
@@ -0,0 +1,508 @@
+/*
+ * 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.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/bitmap.h>
+#include <linux/sched.h>
+#include <linux/poll.h>
+#include <linux/pid.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <asm/cputable.h>
+#include <asm/current.h>
+#include <asm/copro.h>
+
+#include "cxl.h"
+
+#define CXL_NUM_MINORS 256 /* Total to reserve */
+#define CXL_DEV_MINORS 13   /* 1 control + 4 AFUs * 3 (dedicated/master/shared) */
+
+#define CXL_CARD_MINOR(adapter) (adapter->adapter_num * CXL_DEV_MINORS)
+#define CXL_AFU_MINOR_D(afu) (CXL_CARD_MINOR(afu->adapter) + 1 + (3 * afu->slice))
+#define CXL_AFU_MINOR_M(afu) (CXL_AFU_MINOR_D(afu) + 1)
+#define CXL_AFU_MINOR_S(afu) (CXL_AFU_MINOR_D(afu) + 2)
+#define CXL_AFU_MKDEV_D(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_D(afu))
+#define CXL_AFU_MKDEV_M(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_M(afu))
+#define CXL_AFU_MKDEV_S(afu) MKDEV(MAJOR(cxl_dev), CXL_AFU_MINOR_S(afu))
+
+#define CXL_DEVT_ADAPTER(dev) (MINOR(dev) / CXL_DEV_MINORS)
+#define CXL_DEVT_AFU(dev) ((MINOR(dev) % CXL_DEV_MINORS - 1) / 3)
+
+#define CXL_DEVT_IS_CARD(dev) (MINOR(dev) % CXL_DEV_MINORS == 0)
+
+static dev_t cxl_dev;
+
+static struct class *cxl_class;
+
+static int __afu_open(struct inode *inode, struct file *file, bool master)
+{
+        struct cxl *adapter;
+        struct cxl_afu *afu;
+        struct cxl_context *ctx;
+        int adapter_num = CXL_DEVT_ADAPTER(inode->i_rdev);
+        int slice = CXL_DEVT_AFU(inode->i_rdev);
+        int rc = -ENODEV;
+
+        pr_devel("afu_open afu%i.%i\n", slice, adapter_num);
+
+        if (!(adapter = get_cxl_adapter(adapter_num)))
+                return -ENODEV;
+
+        if (slice > adapter->slices)
+                goto err_put_adapter;
+
+        spin_lock(&adapter->afu_list_lock);
+        if (!(afu = adapter->afu[slice])) {
+                spin_unlock(&adapter->afu_list_lock);
+                goto err_put_adapter;
+        }
+        get_device(&afu->dev);
+        spin_unlock(&adapter->afu_list_lock);
+
+        if (!afu->current_mode)
+                goto err_put_afu;
+
+        if (!(ctx = cxl_context_alloc())) {
+                rc = -ENOMEM;
+                goto err_put_afu;
+        }
+
+        if ((rc = cxl_context_init(ctx, afu, master)))
+                goto err_put_afu;
+
+        pr_devel("afu_open pe: %i\n", ctx->pe);
+        file->private_data = ctx;
+        cxl_ctx_get();
+
+        /* Our ref on the AFU will now hold the adapter */
+        put_device(&adapter->dev);
+
+        return 0;
+
+err_put_afu:
+        put_device(&afu->dev);
+err_put_adapter:
+        put_device(&adapter->dev);
+        return rc;
+}
+static int afu_open(struct inode *inode, struct file *file)
+{
+        return __afu_open(inode, file, false);
+}
+
+static int afu_master_open(struct inode *inode, struct file *file)
+{
+        return __afu_open(inode, file, true);
+}
+
+static int afu_release(struct inode *inode, struct file *file)
+{
+        struct cxl_context *ctx = file->private_data;
+
+        pr_devel("%s: closing cxl file descriptor. pe: %i\n",
+                 __func__, ctx->pe);
+        cxl_context_detach(ctx);
+
+        put_device(&ctx->afu->dev);
+
+        /*
+         * At this this point all bottom halfs have finished and we should be
+         * getting no more IRQs from the hardware for this context.  Once it's
+         * removed from the IDR (and RCU synchronised) it's safe to free the
+         * sstp and context.
+         */
+        cxl_context_free(ctx);
+
+        cxl_ctx_put();
+        return 0;
+}
+
+static long afu_ioctl_start_work(struct cxl_context *ctx,
+                                 struct cxl_ioctl_start_work __user *uwork)
+{
+        struct cxl_ioctl_start_work work;
+        u64 amr = 0;
+        int rc;
+
+        pr_devel("%s: pe: %i\n", __func__, ctx->pe);
+
+        mutex_lock(&ctx->status_mutex);
+        if (ctx->status != OPENED) {
+                rc = -EIO;
+                goto out;
+        }
+
+        if (copy_from_user(&work, uwork,
+                           sizeof(struct cxl_ioctl_start_work))) {
+                rc = -EFAULT;
+                goto out;
+        }
+
+        /*
+         * if any of the reserved fields are set or any of the unused
+         * flags are set it's invalid
+         */
+        if (work.reserved1 || work.reserved2 || work.reserved3 ||
+            work.reserved4 || work.reserved5 || work.reserved6 ||
+            (work.flags & ~CXL_START_WORK_ALL)) {
+                rc = -EINVAL;
+                goto out;
+        }
+
+        if (!(work.flags & CXL_START_WORK_NUM_IRQS))
+                work.num_interrupts = ctx->afu->pp_irqs;
+        else if ((work.num_interrupts < ctx->afu->pp_irqs) ||
+                 (work.num_interrupts > ctx->afu->irqs_max)) {
+                rc =  -EINVAL;
+                goto out;
+        }
+        if ((rc = afu_register_irqs(ctx, work.num_interrupts)))
+                goto out;
+
+        if (work.flags & CXL_START_WORK_AMR)
+                amr = work.amr & mfspr(SPRN_UAMOR);
+
+        /*
+         * We grab the PID here and not in the file open to allow for the case
+         * where a process (master, some daemon, etc) has opened the chardev on
+         * behalf of another process, so the AFU's mm gets bound to the process
+         * that performs this ioctl and not the process that opened the file.
+         */
+        ctx->pid = get_pid(get_task_pid(current, PIDTYPE_PID));
+
+        if ((rc = cxl_attach_process(ctx, false, work.work_element_descriptor,
+                                     amr)))
+                goto out;
+
+        ctx->status = STARTED;
+        rc = 0;
+out:
+        mutex_unlock(&ctx->status_mutex);
+        return rc;
+}
+static long afu_ioctl_process_element(struct cxl_context *ctx,
+                                      int __user *upe)
+{
+        pr_devel("%s: pe: %i\n", __func__, ctx->pe);
+
+        if (copy_to_user(upe, &ctx->pe, sizeof(__u32)))
+                return -EFAULT;
+
+        return 0;
+}
+
+static long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+        struct cxl_context *ctx = file->private_data;
+
+        if (ctx->status == CLOSED)
+                return -EIO;
+
+        pr_devel("afu_ioctl\n");
+        switch (cmd) {
+        case CXL_IOCTL_START_WORK:
+                return afu_ioctl_start_work(ctx, (struct cxl_ioctl_start_work __user *)arg);
+        case CXL_IOCTL_GET_PROCESS_ELEMENT:
+                return afu_ioctl_process_element(ctx, (__u32 __user *)arg);
+        }
+        return -EINVAL;
+}
+
+static long afu_compat_ioctl(struct file *file, unsigned int cmd,
+                             unsigned long arg)
+{
+        return afu_ioctl(file, cmd, arg);
+}
+
+static int afu_mmap(struct file *file, struct vm_area_struct *vm)
+{
+        struct cxl_context *ctx = file->private_data;
+
+        /* AFU must be started before we can MMIO */
+        if (ctx->status != STARTED)
+                return -EIO;
+
+        return cxl_context_iomap(ctx, vm);
+}
+
+static unsigned int afu_poll(struct file *file, struct poll_table_struct *poll)
+{
+        struct cxl_context *ctx = file->private_data;
+        int mask = 0;
+        unsigned long flags;
+
+
+        poll_wait(file, &ctx->wq, poll);
+
+        pr_devel("afu_poll wait done pe: %i\n", ctx->pe);
+
+        spin_lock_irqsave(&ctx->lock, flags);
+        if (ctx->pending_irq || ctx->pending_fault ||
+            ctx->pending_afu_err)
+                mask |= POLLIN | POLLRDNORM;
+        else if (ctx->status == CLOSED)
+                /* Only error on closed when there are no futher events pending
+                 */
+                mask |= POLLERR;
+        spin_unlock_irqrestore(&ctx->lock, flags);
+
+        pr_devel("afu_poll pe: %i returning %#x\n", ctx->pe, mask);
+
+        return mask;
+}
+
+static inline int ctx_event_pending(struct cxl_context *ctx)
+{
+        return (ctx->pending_irq || ctx->pending_fault ||
+            ctx->pending_afu_err || (ctx->status == CLOSED));
+}
+
+static ssize_t afu_read(struct file *file, char __user *buf, size_t count,
+                        loff_t *off)
+{
+        struct cxl_context *ctx = file->private_data;
+        struct cxl_event event;
+        unsigned long flags;
+        DEFINE_WAIT(wait);
+
+        if (count < CXL_READ_MIN_SIZE)
+                return -EINVAL;
+
+        spin_lock_irqsave(&ctx->lock, flags);
+
+        for (;;) {
+                prepare_to_wait(&ctx->wq, &wait, TASK_INTERRUPTIBLE);
+                if (ctx_event_pending(ctx))
+                        break;
+
+                spin_unlock_irqrestore(&ctx->lock, flags);
+                if (file->f_flags & O_NONBLOCK)
+                        return -EAGAIN;
+
+                if (signal_pending(current))
+                        return -ERESTARTSYS;
+
+                pr_devel("afu_read going to sleep...\n");
+                schedule();
+                pr_devel("afu_read woken up\n");
+                spin_lock_irqsave(&ctx->lock, flags);
+        }
+
+        finish_wait(&ctx->wq, &wait);
+
+        memset(&event, 0, sizeof(event));
+        event.header.process_element = ctx->pe;
+        event.header.size = sizeof(struct cxl_event_header);
+        if (ctx->pending_irq) {
+                pr_devel("afu_read delivering AFU interrupt\n");
+                event.header.size += sizeof(struct cxl_event_afu_interrupt);
+                event.header.type = CXL_EVENT_AFU_INTERRUPT;
+                event.irq.irq = find_first_bit(ctx->irq_bitmap, ctx->irq_count) + 1;
+                clear_bit(event.irq.irq - 1, ctx->irq_bitmap);
+                if (bitmap_empty(ctx->irq_bitmap, ctx->irq_count))
+                        ctx->pending_irq = false;
+        } else if (ctx->pending_fault) {
+                pr_devel("afu_read delivering data storage fault\n");
+                event.header.size += sizeof(struct cxl_event_data_storage);
+                event.header.type = CXL_EVENT_DATA_STORAGE;
+                event.fault.addr = ctx->fault_addr;
+                event.fault.dsisr = ctx->fault_dsisr;
+                ctx->pending_fault = false;
+        } else if (ctx->pending_afu_err) {
+                pr_devel("afu_read delivering afu error\n");
+                event.header.size += sizeof(struct cxl_event_afu_error);
+                event.header.type = CXL_EVENT_AFU_ERROR;
+                event.afu_error.error = ctx->afu_err;
+                ctx->pending_afu_err = false;
+        } else if (ctx->status == CLOSED) {
+                pr_devel("afu_read fatal error\n");
+                spin_unlock_irqrestore(&ctx->lock, flags);
+                return -EIO;
+        } else
+                WARN(1, "afu_read must be buggy\n");
+
+        spin_unlock_irqrestore(&ctx->lock, flags);
+
+        if (copy_to_user(buf, &event, event.header.size))
+                return -EFAULT;
+        return event.header.size;
+}
+
+static const struct file_operations afu_fops = {
+        .owner          = THIS_MODULE,
+        .open           = afu_open,
+        .poll           = afu_poll,
+        .read           = afu_read,
+        .release        = afu_release,
+        .unlocked_ioctl = afu_ioctl,
+        .compat_ioctl   = afu_compat_ioctl,
+        .mmap           = afu_mmap,
+};
+
+static const struct file_operations afu_master_fops = {
+        .owner          = THIS_MODULE,
+        .open           = afu_master_open,
+        .poll           = afu_poll,
+        .read           = afu_read,
+        .release        = afu_release,
+        .unlocked_ioctl = afu_ioctl,
+        .compat_ioctl   = afu_compat_ioctl,
+        .mmap           = afu_mmap,
+};
+
+
+static char *cxl_devnode(struct device *dev, umode_t *mode)
+{
+        if (CXL_DEVT_IS_CARD(dev->devt)) {
+                /*
+                 * These minor numbers will eventually be used to program the
+                 * PSL and AFUs once we have dynamic reprogramming support
+                 */
+                return NULL;
+        }
+        return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
+}
+
+extern struct class *cxl_class;
+
+static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
+                           struct device **chardev, char *postfix, char *desc,
+                           const struct file_operations *fops)
+{
+        struct device *dev;
+        int rc;
+
+        cdev_init(cdev, fops);
+        if ((rc = cdev_add(cdev, devt, 1))) {
+                dev_err(&afu->dev, "Unable to add %s chardev: %i\n", desc, rc);
+                return rc;
+        }
+
+        dev = device_create(cxl_class, &afu->dev, devt, afu,
+                        "afu%i.%i%s", afu->adapter->adapter_num, afu->slice, postfix);
+        if (IS_ERR(dev)) {
+                dev_err(&afu->dev, "Unable to create %s chardev in sysfs: %i\n", desc, rc);
+                rc = PTR_ERR(dev);
+                goto err;
+        }
+
+        *chardev = dev;
+
+        return 0;
+err:
+        cdev_del(cdev);
+        return rc;
+}
+
+int cxl_chardev_d_afu_add(struct cxl_afu *afu)
+{
+        return cxl_add_chardev(afu, CXL_AFU_MKDEV_D(afu), &afu->afu_cdev_d,
+                               &afu->chardev_d, "d", "dedicated",
+                               &afu_master_fops); /* Uses master fops */
+}
+
+int cxl_chardev_m_afu_add(struct cxl_afu *afu)
+{
+        return cxl_add_chardev(afu, CXL_AFU_MKDEV_M(afu), &afu->afu_cdev_m,
+                               &afu->chardev_m, "m", "master",
+                               &afu_master_fops);
+}
+
+int cxl_chardev_s_afu_add(struct cxl_afu *afu)
+{
+        return cxl_add_chardev(afu, CXL_AFU_MKDEV_S(afu), &afu->afu_cdev_s,
+                               &afu->chardev_s, "s", "shared",
+                               &afu_fops);
+}
+
+void cxl_chardev_afu_remove(struct cxl_afu *afu)
+{
+        if (afu->chardev_d) {
+                cdev_del(&afu->afu_cdev_d);
+                device_unregister(afu->chardev_d);
+                afu->chardev_d = NULL;
+        }
+        if (afu->chardev_m) {
+                cdev_del(&afu->afu_cdev_m);
+                device_unregister(afu->chardev_m);
+                afu->chardev_m = NULL;
+        }
+        if (afu->chardev_s) {
+                cdev_del(&afu->afu_cdev_s);
+                device_unregister(afu->chardev_s);
+                afu->chardev_s = NULL;
+        }
+}
+
+int cxl_register_afu(struct cxl_afu *afu)
+{
+        afu->dev.class = cxl_class;
+
+        return device_register(&afu->dev);
+}
+
+int cxl_register_adapter(struct cxl *adapter)
+{
+        adapter->dev.class = cxl_class;
+
+        /*
+         * Future: When we support dynamically reprogramming the PSL & AFU we
+         * will expose the interface to do that via a chardev:
+         * adapter->dev.devt = CXL_CARD_MKDEV(adapter);
+         */
+
+        return device_register(&adapter->dev);
+}
+
+int __init cxl_file_init(void)
+{
+        int rc;
+
+        /*
+         * If these change we really need to update API.  Either change some
+         * flags or update API version number CXL_API_VERSION.
+         */
+        BUILD_BUG_ON(CXL_API_VERSION != 1);
+        BUILD_BUG_ON(sizeof(struct cxl_ioctl_start_work) != 64);
+        BUILD_BUG_ON(sizeof(struct cxl_event_header) != 8);
+        BUILD_BUG_ON(sizeof(struct cxl_event_afu_interrupt) != 8);
+        BUILD_BUG_ON(sizeof(struct cxl_event_data_storage) != 32);
+        BUILD_BUG_ON(sizeof(struct cxl_event_afu_error) != 16);
+
+        if ((rc = alloc_chrdev_region(&cxl_dev, 0, CXL_NUM_MINORS, "cxl"))) {
+                pr_err("Unable to allocate CXL major number: %i\n", rc);
+                return rc;
+        }
+
+        pr_devel("CXL device allocated, MAJOR %i\n", MAJOR(cxl_dev));
+
+        cxl_class = class_create(THIS_MODULE, "cxl");
+        if (IS_ERR(cxl_class)) {
+                pr_err("Unable to create CXL class\n");
+                rc = PTR_ERR(cxl_class);
+                goto err;
+        }
+        cxl_class->devnode = cxl_devnode;
+
+        return 0;
+
+err:
+        unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
+        return rc;
+}
+
+void cxl_file_exit(void)
+{
+        unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
+        class_destroy(cxl_class);
+}