From: Sjur Brændeland <[email protected]> Add a simple serial connection driver called VIRTIO_ID_RPROC_SERIAL (0xB) for communicating with a remote processor in an asymmetric multi-processing configuration.
This implementation reuses the existing virtio_console implementation, and adds support for DMA allocation of data buffers and disables use of tty console and the virtio control queue. This enables use of the exising virtio_console code in the remoteproc framework. Signed-off-by: Sjur Brændeland <[email protected]> cc: Michael S. Tsirkin <[email protected]> cc: Amit Shah <[email protected]> cc: Ohad Ben-Cohen <[email protected]> cc: Linus Walleij <[email protected]> --- Hi Rusty, Changes since v1: o Use proper macros IS_ENABLED(CONFIG_REMOTEPROC) o Fix bug at registration of rproc_serial driver o Always allocate PAGE_SIZE buffers for rproc_serial, and limit write to port_fops_write to use PAGE_SIZE. Regards, Sjur drivers/char/virtio_console.c | 160 ++++++++++++++++++++++++++++++++++------- include/linux/virtio_ids.h | 1 + 2 files changed, 134 insertions(+), 27 deletions(-) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index cdf2f54..395522a 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -35,6 +35,8 @@ #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" /* @@ -323,6 +325,52 @@ static bool is_console_port(struct port *port) return false; } +#if IS_ENABLED(CONFIG_REMOTEPROC) +static inline bool is_rproc_serial(struct virtio_device *vdev) +{ + return vdev->id.device == VIRTIO_ID_RPROC_SERIAL; +} +#else +static inline bool is_rproc_serial(struct virtio_device *vdev) +{ + return false; +} +#endif + +/* Allocate data buffer from DMA memory if requested */ +static inline void * +alloc_databuf(struct virtio_device *vdev, size_t size, gfp_t flag) +{ + if (is_rproc_serial(vdev)) { + dma_addr_t dma; + struct device *dev = &vdev->dev; + /* + * Allocate DMA memory from ancestors. Finding the ancestor + * is a bit quirky when DMA_MEMORY_INCLUDES_CHILDREN is not + * implemented. + */ + dev = dev->parent ? dev->parent : dev; + dev = dev->parent ? dev->parent : dev; + return dma_alloc_coherent(dev, size, &dma, flag); + } + return kmalloc(size, flag); +} + +static inline void +free_databuf(struct virtio_device *vdev, size_t size, void *cpu_addr) +{ + + if (is_rproc_serial(vdev)) { + struct device *dev = &vdev->dev; + dma_addr_t dma_handle = virt_to_bus(cpu_addr); + dev = dev->parent ? dev->parent : dev; + dev = dev->parent ? dev->parent : dev; + dma_free_coherent(dev, size, cpu_addr, dma_handle); + return; + } + kfree(cpu_addr); +} + static inline bool use_multiport(struct ports_device *portdev) { /* @@ -334,20 +382,22 @@ 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 void +free_buf(struct virtqueue *vq, struct port_buffer *buf, size_t buf_size) { - kfree(buf->buf); + free_databuf(vq->vdev, buf_size, buf->buf); kfree(buf); } -static struct port_buffer *alloc_buf(size_t buf_size) +static struct port_buffer *alloc_buf(struct virtqueue *vq, size_t buf_size) { struct port_buffer *buf; buf = kmalloc(sizeof(*buf), GFP_KERNEL); if (!buf) goto fail; - buf->buf = kzalloc(buf_size, GFP_KERNEL); + buf->buf = alloc_databuf(vq->vdev, buf_size, GFP_KERNEL); + memset(buf->buf, 0, buf_size); if (!buf->buf) goto free_buf; buf->len = 0; @@ -414,7 +464,7 @@ 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(port->in_vq, buf, PAGE_SIZE); } port->inbuf = NULL; buf = get_inbuf(port); @@ -485,7 +535,7 @@ static void reclaim_consumed_buffers(struct port *port) return; } while ((buf = virtqueue_get_buf(port->out_vq, &len))) { - kfree(buf); + free_databuf(port->portdev->vdev, PAGE_SIZE, buf); port->outvq_full = false; } } @@ -672,6 +722,8 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf, char *buf; ssize_t ret; bool nonblock; + struct virtio_device *vdev; + size_t buf_size; /* Userspace could be out to fool us */ if (!count) @@ -694,9 +746,16 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf, if (!port->guest_connected) return -ENODEV; - count = min((size_t)(32 * 1024), count); + vdev = port->portdev->vdev; + + if (is_rproc_serial(vdev)) { + count = min((size_t)PAGE_SIZE, count); + buf_size = PAGE_SIZE; + } else + buf_size = count = min((size_t)(32 * 1024), count); + + buf = alloc_databuf(vdev, buf_size, GFP_KERNEL); - buf = kmalloc(count, GFP_KERNEL); if (!buf) return -ENOMEM; @@ -720,7 +779,7 @@ static ssize_t port_fops_write(struct file *filp, const char __user *ubuf, goto out; free_buf: - kfree(buf); + free_databuf(vdev, buf_size, buf); out: return ret; } @@ -767,6 +826,7 @@ static int port_fops_release(struct inode *inode, struct file *filp) spin_unlock_irq(&port->inbuf_lock); spin_lock_irq(&port->outvq_lock); + reclaim_consumed_buffers(port); spin_unlock_irq(&port->outvq_lock); @@ -918,7 +978,8 @@ static void resize_console(struct port *port) return; vdev = port->portdev->vdev; - if (virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)) + if (!is_rproc_serial(vdev) && + virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)) hvc_resize(port->cons.hvc, port->cons.ws); } @@ -1102,7 +1163,7 @@ 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); if (!buf) break; @@ -1110,7 +1171,7 @@ 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(vq, buf, PAGE_SIZE); break; } nr_added_bufs++; @@ -1198,10 +1259,18 @@ 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, but + * 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; @@ -1234,7 +1303,7 @@ 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(port->in_vq, buf, PAGE_SIZE); free_device: device_destroy(pdrvdata.class, port->dev->devt); free_cdev: @@ -1276,7 +1345,18 @@ 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(port->in_vq, buf, PAGE_SIZE); + + /* + * Remove buffers from out queue for rproc-serial. We cannot afford + * to leak any DMA mem, so reclaim this memory even if this might be + * racy for the remote processor. + */ + if (is_rproc_serial(port->portdev->vdev)) { + while ((buf = virtqueue_detach_unused_buf(port->out_vq))) + free_databuf(port->portdev->vdev, PAGE_SIZE, buf); + } + } /* @@ -1478,7 +1558,7 @@ 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(portdev->c_ivq, buf, PAGE_SIZE); } } spin_unlock(&portdev->cvq_lock); @@ -1674,10 +1754,10 @@ static void remove_controlq_data(struct ports_device *portdev) return; while ((buf = virtqueue_get_buf(portdev->c_ivq, &len))) - free_buf(buf); + free_buf(portdev->c_ivq, buf, PAGE_SIZE); while ((buf = virtqueue_detach_unused_buf(portdev->c_ivq))) - free_buf(buf); + free_buf(portdev->c_ivq, buf, PAGE_SIZE); } /* @@ -1688,7 +1768,7 @@ 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; @@ -1724,10 +1804,12 @@ 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) + if (is_rproc_serial(vdev)) + multiport = false; + else if (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); @@ -1838,6 +1920,16 @@ 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) { @@ -1922,6 +2014,16 @@ 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; @@ -1941,12 +2043,16 @@ static int __init init(void) INIT_LIST_HEAD(&pdrvdata.consoles); INIT_LIST_HEAD(&pdrvdata.portdevs); - return register_virtio_driver(&virtio_console); + err = register_virtio_driver(&virtio_console); + if (err) + return err; + return register_virtio_driver(&virtio_rproc_serial); } static void __exit fini(void) { unregister_virtio_driver(&virtio_console); + unregister_virtio_driver(&virtio_rproc_serial); class_destroy(pdrvdata.class); if (pdrvdata.debugfs_dir) diff --git a/include/linux/virtio_ids.h b/include/linux/virtio_ids.h index 270fb22..07cf6f7 100644 --- a/include/linux/virtio_ids.h +++ b/include/linux/virtio_ids.h @@ -37,5 +37,6 @@ #define VIRTIO_ID_RPMSG 7 /* virtio remote processor messaging */ #define VIRTIO_ID_SCSI 8 /* virtio scsi */ #define VIRTIO_ID_9P 9 /* 9p virtio console */ +#define VIRTIO_ID_RPROC_SERIAL 0xB /* virtio remoteproc serial link */ #endif /* _LINUX_VIRTIO_IDS_H */ -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
