On Thu, Aug 28, 2025 at 05:34:51PM +0800, Haixu Cui wrote:
> This is the virtio SPI Linux kernel driver.
...
> +#include <linux/completion.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/spi/spi.h>
> +#include <linux/stddef.h>
A lot of headers are still missing. See below.
...
> +struct virtio_spi_priv {
> + /* The virtio device we're associated with */
> + struct virtio_device *vdev;
> + /* Pointer to the virtqueue */
> + struct virtqueue *vq;
> + /* Copy of config space mode_func_supported */
> + u32 mode_func_supported;
uXX (in particular u32) is defined in types.h.
> + /* Copy of config space max_freq_hz */
> + u32 max_freq_hz;
> +};
...
> +static int virtio_spi_set_delays(struct spi_transfer_head *th,
> + struct spi_device *spi,
> + struct spi_transfer *xfer)
> +{
> + int cs_setup;
> + int cs_word_delay_xfer;
> + int cs_word_delay_spi;
> + int delay;
> + int cs_hold;
> + int cs_inactive;
> + int cs_change_delay;
> +
> + cs_setup = spi_delay_to_ns(&spi->cs_setup, xfer);
> + if (cs_setup < 0) {
> + dev_warn(&spi->dev, "Cannot convert cs_setup\n");
dev_warn() et al. are defined in dev_printk.h.
> + return cs_setup;
> + }
> + th->cs_setup_ns = cpu_to_le32(cs_setup);
This requires
#include <asm/byteorder.h>
> + cs_word_delay_xfer = spi_delay_to_ns(&xfer->word_delay, xfer);
> + if (cs_word_delay_xfer < 0) {
> + dev_warn(&spi->dev, "Cannot convert cs_word_delay_xfer\n");
> + return cs_word_delay_xfer;
> + }
> + cs_word_delay_spi = spi_delay_to_ns(&spi->word_delay, xfer);
> + if (cs_word_delay_spi < 0) {
> + dev_warn(&spi->dev, "Cannot convert cs_word_delay_spi\n");
> + return cs_word_delay_spi;
> + }
> +
> + th->word_delay_ns = cpu_to_le32(max(cs_word_delay_spi,
> cs_word_delay_xfer));
max() is defined in math.h.
> + delay = spi_delay_to_ns(&xfer->delay, xfer);
> + if (delay < 0) {
> + dev_warn(&spi->dev, "Cannot convert delay\n");
> + return delay;
> + }
> + cs_hold = spi_delay_to_ns(&spi->cs_hold, xfer);
> + if (cs_hold < 0) {
> + dev_warn(&spi->dev, "Cannot convert cs_hold\n");
> + return cs_hold;
> + }
> + th->cs_delay_hold_ns = cpu_to_le32(delay + cs_hold);
> +
> + cs_inactive = spi_delay_to_ns(&spi->cs_inactive, xfer);
> + if (cs_inactive < 0) {
> + dev_warn(&spi->dev, "Cannot convert cs_inactive\n");
> + return cs_inactive;
> + }
> + cs_change_delay = spi_delay_to_ns(&xfer->cs_change_delay, xfer);
> + if (cs_change_delay < 0) {
> + dev_warn(&spi->dev, "Cannot convert cs_change_delay\n");
> + return cs_change_delay;
> + }
> + th->cs_change_delay_inactive_ns =
> + cpu_to_le32(cs_inactive + cs_change_delay);
> +
> + return 0;
> +}
...
> +static int virtio_spi_transfer_one(struct spi_controller *ctrl,
> + struct spi_device *spi,
> + struct spi_transfer *xfer)
> +{
> + struct virtio_spi_priv *priv = spi_controller_get_devdata(ctrl);
> + struct virtio_spi_req *spi_req __free(kfree);
This is incorrect template. It's one of the exceptions when we mix code and
definitions...
> + struct spi_transfer_head *th;
> + struct scatterlist sg_out_head, sg_out_payload;
> + struct scatterlist sg_in_result, sg_in_payload;
+ scatterlist.h
> + struct scatterlist *sgs[4];
> + unsigned int outcnt = 0;
> + unsigned int incnt = 0;
> + int ret;
> + spi_req = kzalloc(sizeof(*spi_req), GFP_KERNEL);
...so this should be
struct virtio_spi_req *spi_req __free(kfree) =
kzalloc(sizeof(*spi_req), GFP_KERNEL);
(or on one line if you are okay with a 100 limit).
And do not forget to include cleanup.h (__free() macro) and
slab.h (kzalloc() API).
> + if (!spi_req)
> + return -ENOMEM;
+ errno.h
But since you already have IS_ERR()/PTR_ERR() use, just
+ err.h
> + init_completion(&spi_req->completion);
> +
> + th = &spi_req->transfer_head;
> +
> + /* Fill struct spi_transfer_head */
> + th->chip_select_id = spi_get_chipselect(spi, 0);
> + th->bits_per_word = spi->bits_per_word;
> + th->cs_change = xfer->cs_change;
> + th->tx_nbits = xfer->tx_nbits;
> + th->rx_nbits = xfer->rx_nbits;
> + th->reserved[0] = 0;
> + th->reserved[1] = 0;
> + th->reserved[2] = 0;
> +
> + static_assert(VIRTIO_SPI_CPHA == SPI_CPHA,
> + "VIRTIO_SPI_CPHA must match SPI_CPHA");
> + static_assert(VIRTIO_SPI_CPOL == SPI_CPOL,
> + "VIRTIO_SPI_CPOL must match SPI_CPOL");
> + static_assert(VIRTIO_SPI_CS_HIGH == SPI_CS_HIGH,
> + "VIRTIO_SPI_CS_HIGH must match SPI_CS_HIGH");
> + static_assert(VIRTIO_SPI_MODE_LSB_FIRST == SPI_LSB_FIRST,
> + "VIRTIO_SPI_MODE_LSB_FIRST must match SPI_LSB_FIRST");
> +
> + th->mode = cpu_to_le32(spi->mode & VIRTIO_SPI_MODE_MASK);
> + if (spi->mode & SPI_LOOP)
> + th->mode |= cpu_to_le32(VIRTIO_SPI_MODE_LOOP);
> +
> + th->freq = cpu_to_le32(xfer->speed_hz);
> +
> + ret = virtio_spi_set_delays(th, spi, xfer);
> + if (ret)
> + goto msg_done;
> +
> + /* Set buffers */
> + spi_req->tx_buf = xfer->tx_buf;
> + spi_req->rx_buf = xfer->rx_buf;
> +
> + /* Prepare sending of virtio message */
> + init_completion(&spi_req->completion);
> +
> + sg_init_one(&sg_out_head, th, sizeof(*th));
> + sgs[outcnt] = &sg_out_head;
> + outcnt++;
> +
> + if (spi_req->tx_buf) {
> + sg_init_one(&sg_out_payload, spi_req->tx_buf, xfer->len);
> + sgs[outcnt] = &sg_out_payload;
> + outcnt++;
> + }
> +
> + if (spi_req->rx_buf) {
> + sg_init_one(&sg_in_payload, spi_req->rx_buf, xfer->len);
> + sgs[outcnt] = &sg_in_payload;
> + incnt++;
> + }
> +
> + sg_init_one(&sg_in_result, &spi_req->result,
> + sizeof(struct spi_transfer_result));
> + sgs[outcnt + incnt] = &sg_in_result;
> + incnt++;
> +
> + ret = virtqueue_add_sgs(priv->vq, sgs, outcnt, incnt, spi_req,
> + GFP_KERNEL);
> + if (ret)
> + goto msg_done;
> +
> + /* Simple implementation: There can be only one transfer in flight */
> + virtqueue_kick(priv->vq);
> +
> + wait_for_completion(&spi_req->completion);
> +
> + /* Read result from message and translate return code */
> + switch (spi_req->result.result) {
> + case VIRTIO_SPI_TRANS_OK:
> + break;
> + case VIRTIO_SPI_PARAM_ERR:
> + ret = -EINVAL;
> + break;
> + case VIRTIO_SPI_TRANS_ERR:
> + ret = -EIO;
> + break;
> + default:
> + ret = -EIO;
> + break;
> + }
> +
> +msg_done:
> + if (ret)
> + ctrl->cur_msg->status = ret;
> +
> + return ret;
> +}
...
> +static int virtio_spi_find_vqs(struct virtio_spi_priv *priv)
> +{
> + struct virtqueue *vq;
> +
> + vq = virtio_find_single_vq(priv->vdev, virtio_spi_msg_done, "spi-rq");
> + if (IS_ERR(vq))
> + return PTR_ERR(vq);
See above.
> + priv->vq = vq;
> + return 0;
> +}
...
> +static int virtio_spi_probe(struct virtio_device *vdev)
> +{
> + struct virtio_spi_priv *priv;
> + struct spi_controller *ctrl;
> + int ret;
> + u32 bus_num;
> +
> + ctrl = devm_spi_alloc_host(&vdev->dev, sizeof(*priv));
> + if (!ctrl)
> + return -ENOMEM;
> +
> + priv = spi_controller_get_devdata(ctrl);
> + priv->vdev = vdev;
> + vdev->priv = priv;
> + device_set_node(&ctrl->dev, dev_fwnode(&vdev->dev));
> + dev_set_drvdata(&vdev->dev, ctrl);
> + ret = device_property_read_u32(&vdev->dev, "spi,bus-num", &bus_num);
+ device.h
+ property.h
> + if (ret || bus_num > S16_MAX)
+ limits.h
> + ctrl->bus_num = -1;
> + else
> + ctrl->bus_num = bus_num;
But why do we need this property at all? And where is it documented in the
device tree bindings?
> + virtio_spi_read_config(vdev);
> +
> + ctrl->transfer_one = virtio_spi_transfer_one;
> +
> + ret = virtio_spi_find_vqs(priv);
> + if (ret)
> + return dev_err_probe(&vdev->dev, ret, "Cannot setup
> virtqueues\n");
> +
> + /* Register cleanup for virtqueues using devm */
> + ret = devm_add_action_or_reset(&vdev->dev, virtio_spi_del_vq, vdev);
> + if (ret)
> + return dev_err_probe(&vdev->dev, ret, "Cannot register
> virtqueue cleanup\n");
> +
> + /* Use devm version to register controller */
> + ret = devm_spi_register_controller(&vdev->dev, ctrl);
> + if (ret)
> + return dev_err_probe(&vdev->dev, ret, "Cannot register
> controller\n");
> +
> + return 0;
> +}
...
> +static struct virtio_device_id virtio_spi_id_table[] = {
The type is or should be defined in mod_devicetable.h.
> + { VIRTIO_ID_SPI, VIRTIO_DEV_ANY_ID },
> + {}
> +};
...
> +static const struct dev_pm_ops virtio_spi_pm_ops = {
The type is defined in pm.h.
> + .freeze = pm_sleep_ptr(virtio_spi_freeze),
> + .restore = pm_sleep_ptr(virtio_spi_restore),
> +};
--
With Best Regards,
Andy Shevchenko
