512 bytes isn't always suitable for all case, let firmware maker decide the best value from resource table. enable by VIRTIO_RPMSG_F_BUFSZ feature bit.
Signed-off-by: Tanmay Shah <[email protected]> --- Changes in v4: squash to virtio rpmsg config patch - Introduce new patch to modify rpmsg.rst documentation - check version is always 1. - check size field is same as size of struct virtio_rpmsg_config - introduce alignment field - check alignment field is power of 2 - check tx and rx buf size is aligned with alignment passed in the structure Changes in v3: - change version field from u16 to u8 - introduce size field in the rpmsg_virtio_config structure - check version field is set to any non-zero value. - check size field is not 0. - Remove field for private config, as not needed for now. - add documentation of rpmsg_virtio_config structure drivers/rpmsg/virtio_rpmsg_bus.c | 129 ++++++++++++++++++++++++----- include/linux/rpmsg/virtio_rpmsg.h | 50 +++++++++++ 2 files changed, 160 insertions(+), 19 deletions(-) create mode 100644 include/linux/rpmsg/virtio_rpmsg.h diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c index 99df1ae07055..a59925f870a4 100644 --- a/drivers/rpmsg/virtio_rpmsg_bus.c +++ b/drivers/rpmsg/virtio_rpmsg_bus.c @@ -15,11 +15,13 @@ #include <linux/idr.h> #include <linux/jiffies.h> #include <linux/kernel.h> +#include <linux/log2.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/rpmsg.h> #include <linux/rpmsg/byteorder.h> #include <linux/rpmsg/ns.h> +#include <linux/rpmsg/virtio_rpmsg.h> #include <linux/scatterlist.h> #include <linux/slab.h> #include <linux/sched.h> @@ -39,7 +41,8 @@ * @tx_bufs: kernel address of tx buffers * @num_rx_buf: total number of rx buffers * @num_tx_buf: total number of tx buffers - * @buf_size: size of one rx or tx buffer + * @rx_buf_size: size of one rx buffer + * @tx_buf_size: size of one tx buffer * @last_tx_buf: index of last tx buffer used * @bufs_dma: dma base addr of the buffers * @tx_lock: protects svq and tx_bufs, to allow concurrent senders. @@ -59,7 +62,8 @@ struct virtproc_info { void *rx_bufs, *tx_bufs; unsigned int num_rx_buf; unsigned int num_tx_buf; - unsigned int buf_size; + unsigned int rx_buf_size; + unsigned int tx_buf_size; int last_tx_buf; dma_addr_t bufs_dma; struct mutex tx_lock; @@ -68,9 +72,6 @@ struct virtproc_info { wait_queue_head_t sendq; }; -/* The feature bitmap for virtio rpmsg */ -#define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */ - /** * struct rpmsg_hdr - common header for all rpmsg messages * @src: source address @@ -128,7 +129,7 @@ struct virtio_rpmsg_channel { * processor. */ #define MAX_RPMSG_NUM_BUFS (256) -#define MAX_RPMSG_BUF_SIZE (512) +#define DEFAULT_RPMSG_BUF_SIZE (512) /* * Local addresses are dynamically allocated on-demand. @@ -444,7 +445,7 @@ static void *get_a_tx_buf(struct virtproc_info *vrp) /* either pick the next unused tx buffer */ if (vrp->last_tx_buf < vrp->num_tx_buf) - ret = vrp->tx_bufs + vrp->buf_size * vrp->last_tx_buf++; + ret = vrp->tx_bufs + vrp->tx_buf_size * vrp->last_tx_buf++; /* or recycle a used one */ else ret = virtqueue_get_buf(vrp->svq, &len); @@ -514,7 +515,7 @@ static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev, * messaging), or to improve the buffer allocator, to support * variable-length buffer sizes. */ - if (len > vrp->buf_size - sizeof(struct rpmsg_hdr)) { + if (len > vrp->tx_buf_size - sizeof(struct rpmsg_hdr)) { dev_err(dev, "message is too big (%d)\n", len); return -EMSGSIZE; } @@ -647,7 +648,7 @@ static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept) struct rpmsg_device *rpdev = ept->rpdev; struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev); - return vch->vrp->buf_size - sizeof(struct rpmsg_hdr); + return vch->vrp->tx_buf_size - sizeof(struct rpmsg_hdr); } static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev, @@ -673,7 +674,7 @@ static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev, * We currently use fixed-sized buffers, so trivially sanitize * the reported payload length. */ - if (len > vrp->buf_size || + if (len > vrp->rx_buf_size || msg_len > (len - sizeof(struct rpmsg_hdr))) { dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg_len); return -EINVAL; @@ -706,7 +707,7 @@ static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev, dev_warn_ratelimited(dev, "msg received with no recipient\n"); /* publish the real size of the buffer */ - rpmsg_sg_init(&sg, msg, vrp->buf_size); + rpmsg_sg_init(&sg, msg, vrp->rx_buf_size); /* add the buffer back to the remote processor's virtqueue */ err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, msg, GFP_KERNEL); @@ -820,10 +821,13 @@ static int rpmsg_probe(struct virtio_device *vdev) struct virtproc_info *vrp; struct virtio_rpmsg_channel *vch = NULL; struct rpmsg_device *rpdev_ns, *rpdev_ctrl; + u16 rpmsg_buf_align = 0; void *bufs_va; int err = 0, i; size_t total_buf_space; bool notify; + u8 version; + u16 size; vrp = kzalloc_obj(*vrp); if (!vrp) @@ -855,9 +859,90 @@ static int rpmsg_probe(struct virtio_device *vdev) else vrp->num_tx_buf = MAX_RPMSG_NUM_BUFS; - vrp->buf_size = MAX_RPMSG_BUF_SIZE; + /* + * If VIRTIO_RPMSG_F_BUFSZ feature is supported, then configure buf + * size from virtio device config space from the resource table. + * If the feature is not supported, then assign default buf size. + */ + if (virtio_has_feature(vdev, VIRTIO_RPMSG_F_BUFSZ)) { + virtio_cread(vdev, struct virtio_rpmsg_config, + version, &version); + + /* for now we support only v1 */ + if (version != RPMSG_VDEV_CONFIG_V1) { + dev_err(&vdev->dev, + "unsupported vdev config version %u\n", version); + err = -EINVAL; + goto vqs_del; + } + + /* size of the config space must match */ + virtio_cread(vdev, struct virtio_rpmsg_config, + size, &size); + if (size != sizeof(struct virtio_rpmsg_config)) { + dev_err(&vdev->dev, "invalid size of vdev config %u\n", + size); + err = -EINVAL; + goto vqs_del; + } - total_buf_space = (vrp->num_rx_buf + vrp->num_tx_buf) * vrp->buf_size; + /* + * Optional alignment applied to each buffer size and to the TX + * buffer base address (e.g. to align buffers on a cache line). + * It must be a power of two; zero means no extra alignment. + */ + virtio_cread(vdev, struct virtio_rpmsg_config, + rpmsg_buf_align, &rpmsg_buf_align); + if (rpmsg_buf_align && !is_power_of_2(rpmsg_buf_align)) { + dev_err(&vdev->dev, + "bad vdev config: rpmsg_buf_align %u is not a power of two\n", + rpmsg_buf_align); + err = -EINVAL; + goto vqs_del; + } + + /* note: tx and rx are defined from remote view */ + virtio_cread(vdev, struct virtio_rpmsg_config, + txbuf_size, &vrp->rx_buf_size); + virtio_cread(vdev, struct virtio_rpmsg_config, + rxbuf_size, &vrp->tx_buf_size); + + /* The buffers must hold at least the rpmsg header */ + if (vrp->rx_buf_size < sizeof(struct rpmsg_hdr) || + vrp->tx_buf_size < sizeof(struct rpmsg_hdr)) { + dev_err(&vdev->dev, + "bad vdev config: rx buf sz = %u, tx buf sz = %u\n", + vrp->rx_buf_size, vrp->tx_buf_size); + err = -EINVAL; + goto vqs_del; + } + + /* + * The buffer size must be aligned to the provided alignment for + * so that the start address of tx bufs can be aligned. + */ + if (rpmsg_buf_align && + (!IS_ALIGNED(vrp->rx_buf_size, rpmsg_buf_align) || + !IS_ALIGNED(vrp->tx_buf_size, rpmsg_buf_align))) { + dev_err(&vdev->dev, + "bad vdev config: buf sizes (rx %u, tx %u) not aligned to %u\n", + vrp->rx_buf_size, vrp->tx_buf_size, + rpmsg_buf_align); + err = -EINVAL; + goto vqs_del; + } + + dev_dbg(&vdev->dev, + "vdev config: ver=%u, align=0x%x, rx sz = 0x%x, tx sz = 0x%x\n", + version, rpmsg_buf_align, vrp->rx_buf_size, + vrp->tx_buf_size); + } else { + vrp->rx_buf_size = DEFAULT_RPMSG_BUF_SIZE; + vrp->tx_buf_size = DEFAULT_RPMSG_BUF_SIZE; + } + + total_buf_space = (vrp->num_rx_buf * vrp->rx_buf_size) + + (vrp->num_tx_buf * vrp->tx_buf_size); /* allocate coherent memory for the buffers */ bufs_va = dma_alloc_coherent(vdev->dev.parent, @@ -874,15 +959,20 @@ static int rpmsg_probe(struct virtio_device *vdev) /* first part of the buffers is dedicated for RX */ vrp->rx_bufs = bufs_va; - /* and second part is dedicated for TX */ - vrp->tx_bufs = bufs_va + vrp->num_rx_buf * vrp->buf_size; + /* + * Here buf_va is aligned to a page. Also rx buf size is aligned with + * cache line alignment provided by the firmware, so tx buf's start + * address is guranteed to be aligned with the alignment provided by + * the firmware. + */ + vrp->tx_bufs = bufs_va + (vrp->num_rx_buf * vrp->rx_buf_size); /* set up the receive buffers */ for (i = 0; i < vrp->num_rx_buf; i++) { struct scatterlist sg; - void *cpu_addr = vrp->rx_bufs + i * vrp->buf_size; + void *cpu_addr = vrp->rx_bufs + i * vrp->rx_buf_size; - rpmsg_sg_init(&sg, cpu_addr, vrp->buf_size); + rpmsg_sg_init(&sg, cpu_addr, vrp->rx_buf_size); err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, cpu_addr, GFP_KERNEL); @@ -965,8 +1055,8 @@ static int rpmsg_remove_device(struct device *dev, void *data) static void rpmsg_remove(struct virtio_device *vdev) { struct virtproc_info *vrp = vdev->priv; - unsigned int num_bufs = vrp->num_rx_buf + vrp->num_tx_buf; - size_t total_buf_space = num_bufs * vrp->buf_size; + size_t total_buf_space = (vrp->num_rx_buf * vrp->rx_buf_size) + + (vrp->num_tx_buf * vrp->tx_buf_size); int ret; virtio_reset_device(vdev); @@ -992,6 +1082,7 @@ static struct virtio_device_id id_table[] = { static unsigned int features[] = { VIRTIO_RPMSG_F_NS, + VIRTIO_RPMSG_F_BUFSZ, }; static struct virtio_driver virtio_ipc_driver = { diff --git a/include/linux/rpmsg/virtio_rpmsg.h b/include/linux/rpmsg/virtio_rpmsg.h new file mode 100644 index 000000000000..7e14da68fd17 --- /dev/null +++ b/include/linux/rpmsg/virtio_rpmsg.h @@ -0,0 +1,50 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) Pinecone Inc. 2019 + * Copyright (C) Xiang Xiao <[email protected]> + * Copyright (C) Advanced Micro Devices, Inc. 2026 + */ + +#ifndef _LINUX_VIRTIO_RPMSG_H +#define _LINUX_VIRTIO_RPMSG_H + +#include <linux/types.h> +#include <linux/virtio_types.h> + +/* The feature bitmap for virtio rpmsg */ +#define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */ +#define VIRTIO_RPMSG_F_BUFSZ 1 /* RP get buffer size from config space */ + +/* Version of struct virtio_rpmsg_config understood by this driver */ +#define RPMSG_VDEV_CONFIG_V1 1 + +/** + * struct virtio_rpmsg_config - config space for rpmsg virtio device + * + * @version: version of this structure, currently %RPMSG_VDEV_CONFIG_V1. + * @reserved: reserved for padding, must be zero. + * @size: size of this structure in bytes. + * @rpmsg_buf_align: required alignment in bytes for each buffer. Must be a + * power of two so that both the buffer sizes and the TX buffer + * base address can be aligned (e.g. to a cache line). + * @reserved1: reserved for padding, must be zero. Keeps the following 32-bit + * fields naturally aligned. + * @txbuf_size: Tx buf size from remote's view. For Linux this is rx buf size. + * @rxbuf_size: Rx buf size from remote's view. For Linux this is tx buf size. + * + * This is the configuration structure shared by the device and the driver, + * read when %VIRTIO_RPMSG_F_BUFSZ is negotiated. The fields are laid out so + * the structure is naturally 32-bit aligned. + */ +struct virtio_rpmsg_config { + u8 version; + u8 reserved; + __virtio16 size; + __virtio16 rpmsg_buf_align; + __virtio16 reserved1; + /* The tx/rx individual buffer size (if VIRTIO_RPMSG_F_BUFSZ) */ + __virtio32 txbuf_size; + __virtio32 rxbuf_size; +} __packed; + +#endif /* _LINUX_VIRTIO_RPMSG_H */ -- 2.34.1
