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Signed-off-by: Harald Mommer --- drivers/spi/Kconfig | 11 + drivers/spi/Makefile | 1 + drivers/spi/spi-virtio.c | 475 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 487 insertions(+) create mode 100644 drivers/spi/spi-virtio.c diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index bc7021da2fe9..0b5cd4c1f06b 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -1125,6 +1125,17 @@ config SPI_UNIPHIER If your SoC supports SCSSI, say Y here. +config SPI_VIRTIO + tristate "Virtio SPI Controller" + depends on SPI_MASTER && VIRTIO + help + This enables the Virtio SPI driver. + + Virtio SPI is an SPI driver for virtual machines using Virtio. + + If your Linux is a virtual machine using Virtio, say Y here. + If unsure, say N. + config SPI_XCOMM tristate "Analog Devices AD-FMCOMMS1-EBZ SPI-I2C-bridge driver" depends on I2C diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index 4ff8d725ba5e..ff2243e44e00 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -146,6 +146,7 @@ spi-thunderx-objs := spi-cavium.o spi-cavium-thunderx.o obj-$(CONFIG_SPI_THUNDERX) += spi-thunderx.o obj-$(CONFIG_SPI_TOPCLIFF_PCH) += spi-topcliff-pch.o obj-$(CONFIG_SPI_UNIPHIER) += spi-uniphier.o +obj-$(CONFIG_SPI_VIRTIO) += spi-virtio.o obj-$(CONFIG_SPI_XCOMM) += spi-xcomm.o obj-$(CONFIG_SPI_XILINX) += spi-xilinx.o obj-$(CONFIG_SPI_XLP) += spi-xlp.o diff --git a/drivers/spi/spi-virtio.c b/drivers/spi/spi-virtio.c new file mode 100644 index 000000000000..700cb36e815f --- /dev/null +++ b/drivers/spi/spi-virtio.c @@ -0,0 +1,475 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * SPI bus driver for the Virtio SPI controller + * Copyright (C) 2023 OpenSynergy GmbH + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* virtio_spi private data structure */ +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; + /* Copy of config space max_freq_hz */ + u32 max_freq_hz; +}; + +struct virtio_spi_req { + struct completion completion; + struct spi_transfer_head transfer_head ____cacheline_aligned; + const uint8_t *tx_buf ____cacheline_aligned; + uint8_t *rx_buf ____cacheline_aligned; + struct spi_transfer_result result ____cacheline_aligned; +}; + +static struct spi_board_info board_info = { + .modalias = "spi-virtio", +}; + +static void virtio_spi_msg_done(struct virtqueue *vq) +{ + struct virtio_spi_req *req; + unsigned int len; + + while ((req = virtqueue_get_buf(vq, &len))) + complete(&req->completion); +} + +/* + * See also + * https://lore.kernel.org/all/6171c1c3-55ba-4f74-ae60-764820cf1caf@quicinc.com + */ +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"); + return cs_setup; + } + th->cs_setup_ns = cpu_to_le32((u32)cs_setup); + + 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; + } + if (cs_word_delay_spi > cs_word_delay_xfer) + th->word_delay_ns = cpu_to_le32((u32)cs_word_delay_spi); + else + th->word_delay_ns = cpu_to_le32((u32)cs_word_delay_xfer); + + 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((u32)delay + (u32)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((u32)cs_inactive + + (u32)cs_change_delay); + + return 0; +} + +static int virtio_spi_one_transfer(struct virtio_spi_req *spi_req, + struct spi_controller *ctrl, + struct spi_message *msg, + struct spi_transfer *xfer) +{ + struct virtio_spi_priv *priv = spi_controller_get_devdata(ctrl); + struct spi_device *spi = msg->spi; + struct spi_transfer_head *th; + struct scatterlist sg_out_head, sg_out_payload; + struct scatterlist sg_in_result, sg_in_payload; + struct scatterlist *sgs[4]; + unsigned int outcnt = 0u; + unsigned int incnt = 0u; + int ret; + + 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; + /* + * Got comment: "The virtio spec for cs_change is *not* what the Linux + * cs_change field does, this will not do the right thing." + * TODO: Understand/discuss this, still unclear what may be wrong here + */ + 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; + + BUILD_BUG_ON(VIRTIO_SPI_CPHA != SPI_CPHA); + BUILD_BUG_ON(VIRTIO_SPI_CPOL != SPI_CPOL); + BUILD_BUG_ON(VIRTIO_SPI_CS_HIGH != SPI_CS_HIGH); + BUILD_BUG_ON(VIRTIO_SPI_MODE_LSB_FIRST != SPI_LSB_FIRST); + + th->mode = cpu_to_le32(spi->mode & (SPI_LSB_FIRST | SPI_CS_HIGH | + SPI_CPOL | SPI_CPHA)); + if ((spi->mode & SPI_LOOP) != 0) + th->mode |= cpu_to_le32(VIRTIO_SPI_MODE_LOOP); + + th->freq = cpu_to_le32(xfer->speed_hz); + + if (virtio_spi_set_delays(th, spi, xfer)) + 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 + incnt] = &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); + +msg_done: + if (ret) + msg->status = ret; + + return ret; +} + +static int virtio_spi_transfer_one_message(struct spi_controller *ctrl, + struct spi_message *msg) +{ + struct virtio_spi_priv *priv = spi_controller_get_devdata(ctrl); + struct virtio_spi_req *spi_req; + struct spi_transfer *xfer; + int ret = 0; + + spi_req = kzalloc(sizeof(*spi_req), GFP_KERNEL); + if (!spi_req) { + ret = -ENOMEM; + goto no_mem; + } + + /* + * Simple implementation: Process message by message and wait for each + * message to be completed by the device side. + */ + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + ret = virtio_spi_one_transfer(spi_req, ctrl, msg, xfer); + if (ret) + goto msg_done; + + virtqueue_kick(priv->vq); + + wait_for_completion(&spi_req->completion); + + /* Read result from message */ + ret = (int)spi_req->result.result; + if (ret) + goto msg_done; + } + +msg_done: + kfree(spi_req); +no_mem: + msg->status = ret; + spi_finalize_current_message(ctrl); + + return ret; +} + +static void virtio_spi_read_config(struct virtio_device *vdev) +{ + struct spi_controller *ctrl = dev_get_drvdata(&vdev->dev); + struct virtio_spi_priv *priv = vdev->priv; + u8 cs_max_number; + u8 tx_nbits_supported; + u8 rx_nbits_supported; + + cs_max_number = virtio_cread8(vdev, offsetof(struct virtio_spi_config, + cs_max_number)); + ctrl->num_chipselect = cs_max_number; + + /* Set the mode bits which are understood by this driver */ + priv->mode_func_supported = + virtio_cread32(vdev, offsetof(struct virtio_spi_config, + mode_func_supported)); + ctrl->mode_bits = priv->mode_func_supported & + (VIRTIO_SPI_CS_HIGH | VIRTIO_SPI_MODE_LSB_FIRST); + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_CPHA_1) != 0) + ctrl->mode_bits |= VIRTIO_SPI_CPHA; + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_CPOL_1) != 0) + ctrl->mode_bits |= VIRTIO_SPI_CPOL; + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_LSB_FIRST) != 0) + ctrl->mode_bits |= SPI_LSB_FIRST; + if ((priv->mode_func_supported & VIRTIO_SPI_MF_SUPPORT_LOOPBACK) != 0) + ctrl->mode_bits |= SPI_LOOP; + tx_nbits_supported = + virtio_cread8(vdev, offsetof(struct virtio_spi_config, + tx_nbits_supported)); + if ((tx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_DUAL) != 0) + ctrl->mode_bits |= SPI_TX_DUAL; + if ((tx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_QUAD) != 0) + ctrl->mode_bits |= SPI_TX_QUAD; + if ((tx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_OCTAL) != 0) + ctrl->mode_bits |= SPI_TX_OCTAL; + rx_nbits_supported = + virtio_cread8(vdev, offsetof(struct virtio_spi_config, + rx_nbits_supported)); + if ((rx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_DUAL) != 0) + ctrl->mode_bits |= SPI_RX_DUAL; + if ((rx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_QUAD) != 0) + ctrl->mode_bits |= SPI_RX_QUAD; + if ((rx_nbits_supported & VIRTIO_SPI_RX_TX_SUPPORT_OCTAL) != 0) + ctrl->mode_bits |= SPI_RX_OCTAL; + + ctrl->bits_per_word_mask = + virtio_cread32(vdev, offsetof(struct virtio_spi_config, + bits_per_word_mask)); + + priv->max_freq_hz = + virtio_cread32(vdev, offsetof(struct virtio_spi_config, + max_freq_hz)); +} + +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 (int)PTR_ERR(vq); + priv->vq = vq; + return 0; +} + +/* Function must not be called before virtio_spi_find_vqs() has been run */ +static void virtio_spi_del_vq(struct virtio_device *vdev) +{ + virtio_reset_device(vdev); + vdev->config->del_vqs(vdev); +} + +static int virtio_spi_validate(struct virtio_device *vdev) +{ + /* + * SPI needs always access to the config space. + * Check that the driver can access the config space + */ + if (!vdev->config->get) { + dev_err(&vdev->dev, "%s failure: config access disabled\n", + __func__); + return -EINVAL; + } + + if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) { + dev_err(&vdev->dev, + "device does not comply with spec version 1.x\n"); + return -EINVAL; + } + + return 0; +} + +static int virtio_spi_probe(struct virtio_device *vdev) +{ + struct device_node *np = vdev->dev.parent->of_node; + struct virtio_spi_priv *priv; + struct spi_controller *ctrl; + int err; + u32 bus_num; + u16 csi; + + ctrl = devm_spi_alloc_host(&vdev->dev, sizeof(*priv)); + if (!ctrl) { + dev_err(&vdev->dev, "Kernel memory exhausted in %s()\n", + __func__); + return -ENOMEM; + } + + priv = spi_controller_get_devdata(ctrl); + priv->vdev = vdev; + vdev->priv = priv; + dev_set_drvdata(&vdev->dev, ctrl); + + err = of_property_read_u32(np, "spi,bus-num", &bus_num); + if (!err && bus_num <= S16_MAX) + ctrl->bus_num = (s16)bus_num; + + virtio_spi_read_config(vdev); + + /* Method to transfer a single SPI message */ + ctrl->transfer_one_message = virtio_spi_transfer_one_message; + + /* Initialize virtqueues */ + err = virtio_spi_find_vqs(priv); + if (err) { + dev_err(&vdev->dev, "Cannot setup virtqueues\n"); + return err; + } + + err = spi_register_controller(ctrl); + if (err) { + dev_err(&vdev->dev, "Cannot register controller\n"); + goto err_return; + } + + board_info.max_speed_hz = priv->max_freq_hz; + /* spi_new_device() currently does not use bus_num but better set it */ + board_info.bus_num = (u16)ctrl->bus_num; + + /* Add chip selects to controller */ + for (csi = 0; csi < ctrl->num_chipselect; csi++) { + dev_dbg(&vdev->dev, "Setting up CS=%u\n", csi); + board_info.chip_select = csi; + /* TODO: Discuss setting of board_info.mode */ + if (!(priv->mode_func_supported & VIRTIO_SPI_CS_HIGH)) + board_info.mode = SPI_MODE_0; + else + board_info.mode = SPI_MODE_0 | SPI_CS_HIGH; + if (!spi_new_device(ctrl, &board_info)) { + dev_err(&vdev->dev, "Cannot setup device %u\n", csi); + spi_unregister_controller(ctrl); + err = -ENODEV; + goto err_return; + } + } + + return 0; + +err_return: + vdev->config->del_vqs(vdev); + return err; +} + +static void virtio_spi_remove(struct virtio_device *vdev) +{ + struct spi_controller *ctrl = dev_get_drvdata(&vdev->dev); + + /* Order: 1.) unregister controller, 2.) remove virtqueue */ + spi_unregister_controller(ctrl); + virtio_spi_del_vq(vdev); +} + +static int virtio_spi_freeze(struct virtio_device *vdev) +{ + struct device *dev = &vdev->dev; + struct spi_controller *ctrl = dev_get_drvdata(dev); + int ret; + + /* Stop the queue running */ + ret = spi_controller_suspend(ctrl); + if (ret) { + dev_warn(dev, "cannot suspend controller (%d)\n", ret); + return ret; + } + + virtio_spi_del_vq(vdev); + return 0; +} + +static int virtio_spi_restore(struct virtio_device *vdev) +{ + struct device *dev = &vdev->dev; + struct spi_controller *ctrl = dev_get_drvdata(dev); + int ret; + + ret = virtio_spi_find_vqs(vdev->priv); + if (ret) { + dev_err(dev, "problem starting vqueue (%d)\n", ret); + return ret; + } + + ret = spi_controller_resume(ctrl); + if (ret) + dev_err(dev, "problem resuming controller (%d)\n", ret); + + return ret; +} + +static struct virtio_device_id virtio_spi_id_table[] = { + { VIRTIO_ID_SPI, VIRTIO_DEV_ANY_ID }, + { 0 }, +}; + +static struct virtio_driver virtio_spi_driver = { + .driver.name = KBUILD_MODNAME, + .driver.owner = THIS_MODULE, + .id_table = virtio_spi_id_table, + .validate = virtio_spi_validate, + .probe = virtio_spi_probe, + .remove = virtio_spi_remove, + .freeze = pm_sleep_ptr(virtio_spi_freeze), + .restore = pm_sleep_ptr(virtio_spi_restore), +}; + +module_virtio_driver(virtio_spi_driver); +MODULE_DEVICE_TABLE(virtio, virtio_spi_id_table); + +MODULE_AUTHOR("OpenSynergy GmbH"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Virtio SPI bus driver");