1 files changed, 227 insertions, 100 deletions

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 8ab9c3d4bf13..684b0d53764f 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -37,8 +37,12 @@
 #include <linux/wait.h>
 #include <linux/workqueue.h>
 #include <linux/module.h>
+#include <linux/dma-mapping.h>
+#include <linux/kconfig.h>
 #include "../tty/hvc/hvc_console.h"
 
+#define is_rproc_enabled IS_ENABLED(CONFIG_REMOTEPROC)
+
 /*
  * This is a global struct for storing common data for all the devices
  * this driver handles.
@@ -111,6 +115,21 @@ struct port_buffer {
         size_t len;
         /* offset in the buf from which to consume data */
         size_t offset;
+
+        /* DMA address of buffer */
+        dma_addr_t dma;
+
+        /* Device we got DMA memory from */
+        struct device *dev;
+
+        /* List of pending dma buffers to free */
+        struct list_head list;
+
+        /* If sgpages == 0 then buf is used */
+        unsigned int sgpages;
+
+        /* sg is used if spages > 0. sg must be the last in is struct */
+        struct scatterlist sg[0];
 };
 
 /*
@@ -325,6 +344,11 @@ static bool is_console_port(struct port *port)
         return false;
 }
 
+static bool is_rproc_serial(const struct virtio_device *vdev)
+{
+        return is_rproc_enabled && vdev->id.device == VIRTIO_ID_RPROC_SERIAL;
+}
+
 static inline bool use_multiport(struct ports_device *portdev)
 {
         /*
@@ -336,20 +360,110 @@ static inline bool use_multiport(struct ports_device *portdev)
         return portdev->vdev->features[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 }
 
-static void free_buf(struct port_buffer *buf)
+static DEFINE_SPINLOCK(dma_bufs_lock);
+static LIST_HEAD(pending_free_dma_bufs);
+
+static void free_buf(struct port_buffer *buf, bool can_sleep)
 {
-        kfree(buf->buf);
+        unsigned int i;
+
+        for (i = 0; i < buf->sgpages; i++) {
+                struct page *page = sg_page(&buf->sg[i]);
+                if (!page)
+                        break;
+                put_page(page);
+        }
+
+        if (!buf->dev) {
+                kfree(buf->buf);
+        } else if (is_rproc_enabled) {
+                unsigned long flags;
+
+                /* dma_free_coherent requires interrupts to be enabled. */
+                if (!can_sleep) {
+                        /* queue up dma-buffers to be freed later */
+                        spin_lock_irqsave(&dma_bufs_lock, flags);
+                        list_add_tail(&buf->list, &pending_free_dma_bufs);
+                        spin_unlock_irqrestore(&dma_bufs_lock, flags);
+                        return;
+                }
+                dma_free_coherent(buf->dev, buf->size, buf->buf, buf->dma);
+
+                /* Release device refcnt and allow it to be freed */
+                put_device(buf->dev);
+        }
+
         kfree(buf);
 }
 
-static struct port_buffer *alloc_buf(size_t buf_size)
+static void reclaim_dma_bufs(void)
+{
+        unsigned long flags;
+        struct port_buffer *buf, *tmp;
+        LIST_HEAD(tmp_list);
+
+        if (list_empty(&pending_free_dma_bufs))
+                return;
+
+        /* Create a copy of the pending_free_dma_bufs while holding the lock */
+        spin_lock_irqsave(&dma_bufs_lock, flags);
+        list_cut_position(&tmp_list, &pending_free_dma_bufs,
+                          pending_free_dma_bufs.prev);
+        spin_unlock_irqrestore(&dma_bufs_lock, flags);
+
+        /* Release the dma buffers, without irqs enabled */
+        list_for_each_entry_safe(buf, tmp, &tmp_list, list) {
+                list_del(&buf->list);
+                free_buf(buf, true);
+        }
+}
+
+static struct port_buffer *alloc_buf(struct virtqueue *vq, size_t buf_size,
+                                     int pages)
 {
         struct port_buffer *buf;
 
-        buf = kmalloc(sizeof(*buf), GFP_KERNEL);
+        reclaim_dma_bufs();
+
+        /*
+         * Allocate buffer and the sg list. The sg list array is allocated
+         * directly after the port_buffer struct.
+         */
+        buf = kmalloc(sizeof(*buf) + sizeof(struct scatterlist) * pages,
+                      GFP_KERNEL);
         if (!buf)
                 goto fail;
-        buf->buf = kzalloc(buf_size, GFP_KERNEL);
+
+        buf->sgpages = pages;
+        if (pages > 0) {
+                buf->dev = NULL;
+                buf->buf = NULL;
+                return buf;
+        }
+
+        if (is_rproc_serial(vq->vdev)) {
+                /*
+                 * Allocate DMA memory from ancestor. When a virtio
+                 * device is created by remoteproc, the DMA memory is
+                 * associated with the grandparent device:
+                 * vdev => rproc => platform-dev.
+                 * The code here would have been less quirky if
+                 * DMA_MEMORY_INCLUDES_CHILDREN had been supported
+                 * in dma-coherent.c
+                 */
+                if (!vq->vdev->dev.parent || !vq->vdev->dev.parent->parent)
+                        goto free_buf;
+                buf->dev = vq->vdev->dev.parent->parent;
+
+                /* Increase device refcnt to avoid freeing it */
+                get_device(buf->dev);
+                buf->buf = dma_alloc_coherent(buf->dev, buf_size, &buf->dma,
+                                              GFP_KERNEL);
+        } else {
+                buf->dev = NULL;
+                buf->buf = kmalloc(buf_size, GFP_KERNEL);
+        }
+
         if (!buf->buf)
                 goto free_buf;
         buf->len = 0;
@@ -396,6 +510,8 @@ static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf)
 
         ret = virtqueue_add_buf(vq, sg, 0, 1, buf, GFP_ATOMIC);
         virtqueue_kick(vq);
+        if (!ret)
+                ret = vq->num_free;
         return ret;
 }
 
@@ -416,7 +532,7 @@ static void discard_port_data(struct port *port)
                 port->stats.bytes_discarded += buf->len - buf->offset;
                 if (add_inbuf(port->in_vq, buf) < 0) {
                         err++;
-                        free_buf(buf);
+                        free_buf(buf, false);
                 }
                 port->inbuf = NULL;
                 buf = get_inbuf(port);
@@ -459,7 +575,7 @@ static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id,
         vq = portdev->c_ovq;
 
         sg_init_one(sg, &cpkt, sizeof(cpkt));
-        if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt, GFP_ATOMIC) >= 0) {
+        if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt, GFP_ATOMIC) == 0) {
                 virtqueue_kick(vq);
                 while (!virtqueue_get_buf(vq, &len))
                         cpu_relax();
@@ -476,55 +592,29 @@ static ssize_t send_control_msg(struct port *port, unsigned int event,
         return 0;
 }
 
-struct buffer_token {
-        union {
-                void *buf;
-                struct scatterlist *sg;
-        } u;
-        /* If sgpages == 0 then buf is used, else sg is used */
-        unsigned int sgpages;
-};
-
-static void reclaim_sg_pages(struct scatterlist *sg, unsigned int nrpages)
-{
-        int i;
-        struct page *page;
-
-        for (i = 0; i < nrpages; i++) {
-                page = sg_page(&sg[i]);
-                if (!page)
-                        break;
-                put_page(page);
-        }
-        kfree(sg);
-}
 
 /* Callers must take the port->outvq_lock */
 static void reclaim_consumed_buffers(struct port *port)
 {
-        struct buffer_token *tok;
+        struct port_buffer *buf;
         unsigned int len;
 
         if (!port->portdev) {
                 /* Device has been unplugged.  vqs are already gone. */
                 return;
         }
-        while ((tok = virtqueue_get_buf(port->out_vq, &len))) {
-                if (tok->sgpages)
-                        reclaim_sg_pages(tok->u.sg, tok->sgpages);
-                else
-                        kfree(tok->u.buf);
-                kfree(tok);
+        while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
+                free_buf(buf, false);
                 port->outvq_full = false;
         }
 }
 
 static ssize_t __send_to_port(struct port *port, struct scatterlist *sg,
                               int nents, size_t in_count,
-                              struct buffer_token *tok, bool nonblock)
+                              void *data, bool nonblock)
 {
         struct virtqueue *out_vq;
-        ssize_t ret;
+        int err;
         unsigned long flags;
         unsigned int len;
 
@@ -534,17 +624,17 @@ static ssize_t __send_to_port(struct port *port, struct scatterlist *sg,
 
         reclaim_consumed_buffers(port);
 
-        ret = virtqueue_add_buf(out_vq, sg, nents, 0, tok, GFP_ATOMIC);
+        err = virtqueue_add_buf(out_vq, sg, nents, 0, data, GFP_ATOMIC);
 
         /* Tell Host to go! */
         virtqueue_kick(out_vq);
 
-        if (ret < 0) {
+        if (err) {
                 in_count = 0;
                 goto done;
         }
 
-        if (ret == 0)
+        if (out_vq->num_free == 0)
                 port->outvq_full = true;
 
         if (nonblock)
@@ -572,37 +662,6 @@ done:
         return in_count;
 }
 
-static ssize_t send_buf(struct port *port, void *in_buf, size_t in_count,
-                        bool nonblock)
-{
-        struct scatterlist sg[1];
-        struct buffer_token *tok;
-
-        tok = kmalloc(sizeof(*tok), GFP_ATOMIC);
-        if (!tok)
-                return -ENOMEM;
-        tok->sgpages = 0;
-        tok->u.buf = in_buf;
-
-        sg_init_one(sg, in_buf, in_count);
-
-        return __send_to_port(port, sg, 1, in_count, tok, nonblock);
-}
-
-static ssize_t send_pages(struct port *port, struct scatterlist *sg, int nents,
-                          size_t in_count, bool nonblock)
-{
-        struct buffer_token *tok;
-
-        tok = kmalloc(sizeof(*tok), GFP_ATOMIC);
-        if (!tok)
-                return -ENOMEM;
-        tok->sgpages = nents;
-        tok->u.sg = sg;
-
-        return __send_to_port(port, sg, nents, in_count, tok, nonblock);
-}
-
 /*
  * Give out the data that's requested from the buffer that we have
  * queued up.
@@ -748,9 +807,10 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
                                size_t count, loff_t *offp)
 {
         struct port *port;
-        char *buf;
+        struct port_buffer *buf;
         ssize_t ret;
         bool nonblock;
+        struct scatterlist sg[1];
 
         /* Userspace could be out to fool us */
         if (!count)
@@ -766,11 +826,11 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
 
         count = min((size_t)(32 * 1024), count);
 
-        buf = kmalloc(count, GFP_KERNEL);
+        buf = alloc_buf(port->out_vq, count, 0);
         if (!buf)
                 return -ENOMEM;
 
-        ret = copy_from_user(buf, ubuf, count);
+        ret = copy_from_user(buf->buf, ubuf, count);
         if (ret) {
                 ret = -EFAULT;
                 goto free_buf;
@@ -784,13 +844,14 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf,
          * through to the host.
          */
         nonblock = true;
-        ret = send_buf(port, buf, count, nonblock);
+        sg_init_one(sg, buf->buf, count);
+        ret = __send_to_port(port, sg, 1, count, buf, nonblock);
 
         if (nonblock && ret > 0)
                 goto out;
 
 free_buf:
-        kfree(buf);
+        free_buf(buf, true);
 out:
         return ret;
 }
@@ -856,6 +917,7 @@ static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
         struct port *port = filp->private_data;
         struct sg_list sgl;
         ssize_t ret;
+        struct port_buffer *buf;
         struct splice_desc sd = {
                 .total_len = len,
                 .flags = flags,
@@ -863,22 +925,34 @@ static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
                 .u.data = &sgl,
         };
 
+        /*
+         * Rproc_serial does not yet support splice. To support splice
+         * pipe_to_sg() must allocate dma-buffers and copy content from
+         * regular pages to dma pages. And alloc_buf and free_buf must
+         * support allocating and freeing such a list of dma-buffers.
+         */
+        if (is_rproc_serial(port->out_vq->vdev))
+                return -EINVAL;
+
         ret = wait_port_writable(port, filp->f_flags & O_NONBLOCK);
         if (ret < 0)
                 return ret;
 
+        buf = alloc_buf(port->out_vq, 0, pipe->nrbufs);
+        if (!buf)
+                return -ENOMEM;
+
         sgl.n = 0;
         sgl.len = 0;
         sgl.size = pipe->nrbufs;
-        sgl.sg = kmalloc(sizeof(struct scatterlist) * sgl.size, GFP_KERNEL);
-        if (unlikely(!sgl.sg))
-                return -ENOMEM;
-
+        sgl.sg = buf->sg;
         sg_init_table(sgl.sg, sgl.size);
         ret = __splice_from_pipe(pipe, &sd, pipe_to_sg);
         if (likely(ret > 0))
-                ret = send_pages(port, sgl.sg, sgl.n, sgl.len, true);
+                ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true);
 
+        if (unlikely(ret <= 0))
+                free_buf(buf, true);
         return ret;
 }
 
@@ -927,6 +1001,7 @@ static int port_fops_release(struct inode *inode, struct file *filp)
         reclaim_consumed_buffers(port);
         spin_unlock_irq(&port->outvq_lock);
 
+        reclaim_dma_bufs();
         /*
          * Locks aren't necessary here as a port can't be opened after
          * unplug, and if a port isn't unplugged, a kref would already
@@ -1031,6 +1106,7 @@ static const struct file_operations port_fops = {
 static int put_chars(u32 vtermno, const char *buf, int count)
 {
         struct port *port;
+        struct scatterlist sg[1];
 
         if (unlikely(early_put_chars))
                 return early_put_chars(vtermno, buf, count);
@@ -1039,7 +1115,8 @@ static int put_chars(u32 vtermno, const char *buf, int count)
         if (!port)
                 return -EPIPE;
 
-        return send_buf(port, (void *)buf, count, false);
+        sg_init_one(sg, buf, count);
+        return __send_to_port(port, sg, 1, count, (void *)buf, false);
 }
 
 /*
@@ -1076,7 +1153,10 @@ static void resize_console(struct port *port)
                 return;
 
         vdev = port->portdev->vdev;
-        if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
+
+        /* Don't test F_SIZE at all if we're rproc: not a valid feature! */
+        if (!is_rproc_serial(vdev) &&
+            virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
                 hvc_resize(port->cons.hvc, port->cons.ws);
 }
 
@@ -1260,7 +1340,7 @@ static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
 
         nr_added_bufs = 0;
         do {
-                buf = alloc_buf(PAGE_SIZE);
+                buf = alloc_buf(vq, PAGE_SIZE, 0);
                 if (!buf)
                         break;
 
@@ -1268,7 +1348,7 @@ static unsigned int fill_queue(struct virtqueue *vq, spinlock_t *lock)
                 ret = add_inbuf(vq, buf);
                 if (ret < 0) {
                         spin_unlock_irq(lock);
-                        free_buf(buf);
+                        free_buf(buf, true);
                         break;
                 }
                 nr_added_bufs++;
@@ -1356,10 +1436,18 @@ static int add_port(struct ports_device *portdev, u32 id)
                 goto free_device;
         }
 
-        /*
-         * If we're not using multiport support, this has to be a console port
-         */
-        if (!use_multiport(port->portdev)) {
+        if (is_rproc_serial(port->portdev->vdev))
+                /*
+                 * For rproc_serial assume remote processor is connected.
+                 * rproc_serial does not want the console port, only
+                 * the generic port implementation.
+                 */
+                port->host_connected = true;
+        else if (!use_multiport(port->portdev)) {
+                /*
+                 * If we're not using multiport support,
+                 * this has to be a console port.
+                 */
                 err = init_port_console(port);
                 if (err)
                         goto free_inbufs;
@@ -1392,7 +1480,7 @@ static int add_port(struct ports_device *portdev, u32 id)
 
 free_inbufs:
         while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
-                free_buf(buf);
+                free_buf(buf, true);
 free_device:
         device_destroy(pdrvdata.class, port->dev->devt);
 free_cdev:
@@ -1434,7 +1522,11 @@ static void remove_port_data(struct port *port)
 
         /* Remove buffers we queued up for the Host to send us data in. */
         while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
-                free_buf(buf);
+                free_buf(buf, true);
+
+        /* Free pending buffers from the out-queue. */
+        while ((buf = virtqueue_detach_unused_buf(port->out_vq)))
+                free_buf(buf, true);
 }
 
 /*
@@ -1636,7 +1728,7 @@ static void control_work_handler(struct work_struct *work)
                 if (add_inbuf(portdev->c_ivq, buf) < 0) {
                         dev_warn(&portdev->vdev->dev,
                                  "Error adding buffer to queue\n");
-                        free_buf(buf);
+                        free_buf(buf, false);
                 }
         }
         spin_unlock(&portdev->cvq_lock);
@@ -1832,10 +1924,10 @@ static void remove_controlq_data(struct ports_device *portdev)
                 return;
 
         while ((buf = virtqueue_get_buf(portdev->c_ivq, &len)))
-                free_buf(buf);
+                free_buf(buf, true);
 
         while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq)))
-                free_buf(buf);
+                free_buf(buf, true);
 }
 
 /*
@@ -1846,7 +1938,7 @@ static void remove_controlq_data(struct ports_device *portdev)
  * config space to see how many ports the host has spawned.  We
  * initialize each port found.
  */
-static int __devinit virtcons_probe(struct virtio_device *vdev)
+static int virtcons_probe(struct virtio_device *vdev)
 {
         struct ports_device *portdev;
         int err;
@@ -1882,11 +1974,15 @@ static int __devinit virtcons_probe(struct virtio_device *vdev)
 
         multiport = false;
         portdev->config.max_nr_ports = 1;
-        if (virtio_config_val(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
-                              offsetof(struct virtio_console_config,
-                                       max_nr_ports),
-                              &portdev->config.max_nr_ports) == 0)
+
+        /* Don't test MULTIPORT at all if we're rproc: not a valid feature! */
+        if (!is_rproc_serial(vdev) &&
+            virtio_config_val(vdev, VIRTIO_CONSOLE_F_MULTIPORT,
+                                  offsetof(struct virtio_console_config,
+                                           max_nr_ports),
+                                  &portdev->config.max_nr_ports) == 0) {
                 multiport = true;
+        }
 
         err = init_vqs(portdev);
         if (err < 0) {
@@ -1996,6 +2092,16 @@ static unsigned int features[] = {
         VIRTIO_CONSOLE_F_MULTIPORT,
 };
 
+static struct virtio_device_id rproc_serial_id_table[] = {
+#if IS_ENABLED(CONFIG_REMOTEPROC)
+        { VIRTIO_ID_RPROC_SERIAL, VIRTIO_DEV_ANY_ID },
+#endif
+        { 0 },
+};
+
+static unsigned int rproc_serial_features[] = {
+};
+
 #ifdef CONFIG_PM
 static int virtcons_freeze(struct virtio_device *vdev)
 {
@@ -2080,6 +2186,16 @@ static struct virtio_driver virtio_console = {
 #endif
 };
 
+static struct virtio_driver virtio_rproc_serial = {
+        .feature_table = rproc_serial_features,
+        .feature_table_size = ARRAY_SIZE(rproc_serial_features),
+        .driver.name =  "virtio_rproc_serial",
+        .driver.owner = THIS_MODULE,
+        .id_table =     rproc_serial_id_table,
+        .probe =        virtcons_probe,
+        .remove =       virtcons_remove,
+};
+
 static int __init init(void)
 {
         int err;
@@ -2104,7 +2220,15 @@ static int __init init(void)
                 pr_err("Error %d registering virtio driver\n", err);
                 goto free;
         }
+        err = register_virtio_driver(&virtio_rproc_serial);
+        if (err < 0) {
+                pr_err("Error %d registering virtio rproc serial driver\n",
+                       err);
+                goto unregister;
+        }
         return 0;
+unregister:
+        unregister_virtio_driver(&virtio_console);
 free:
         if (pdrvdata.debugfs_dir)
                 debugfs_remove_recursive(pdrvdata.debugfs_dir);
@@ -2114,7 +2238,10 @@ free:
 
 static void __exit fini(void)
 {
+        reclaim_dma_bufs();
+
         unregister_virtio_driver(&virtio_console);
+        unregister_virtio_driver(&virtio_rproc_serial);
 
         class_destroy(pdrvdata.class);
         if (pdrvdata.debugfs_dir)