diff options
Diffstat (limited to 'drivers/firmware/arm_scmi/mailbox.c')
| -rw-r--r-- | drivers/firmware/arm_scmi/mailbox.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/drivers/firmware/arm_scmi/mailbox.c b/drivers/firmware/arm_scmi/mailbox.c new file mode 100644 index 000000000000..73077bbc4ad9 --- /dev/null +++ b/drivers/firmware/arm_scmi/mailbox.c @@ -0,0 +1,184 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * System Control and Management Interface (SCMI) Message Mailbox Transport + * driver. + * + * Copyright (C) 2019 ARM Ltd. + */ + +#include <linux/err.h> +#include <linux/device.h> +#include <linux/mailbox_client.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/slab.h> + +#include "common.h" + +/** + * struct scmi_mailbox - Structure representing a SCMI mailbox transport + * + * @cl: Mailbox Client + * @chan: Transmit/Receive mailbox channel + * @cinfo: SCMI channel info + * @shmem: Transmit/Receive shared memory area + */ +struct scmi_mailbox { + struct mbox_client cl; + struct mbox_chan *chan; + struct scmi_chan_info *cinfo; + struct scmi_shared_mem __iomem *shmem; +}; + +#define client_to_scmi_mailbox(c) container_of(c, struct scmi_mailbox, cl) + +static void tx_prepare(struct mbox_client *cl, void *m) +{ + struct scmi_mailbox *smbox = client_to_scmi_mailbox(cl); + + shmem_tx_prepare(smbox->shmem, m); +} + +static void rx_callback(struct mbox_client *cl, void *m) +{ + struct scmi_mailbox *smbox = client_to_scmi_mailbox(cl); + + scmi_rx_callback(smbox->cinfo, shmem_read_header(smbox->shmem)); +} + +static bool mailbox_chan_available(struct device *dev, int idx) +{ + return !of_parse_phandle_with_args(dev->of_node, "mboxes", + "#mbox-cells", idx, NULL); +} + +static int mailbox_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, + bool tx) +{ + const char *desc = tx ? "Tx" : "Rx"; + struct device *cdev = cinfo->dev; + struct scmi_mailbox *smbox; + struct device_node *shmem; + int ret, idx = tx ? 0 : 1; + struct mbox_client *cl; + resource_size_t size; + struct resource res; + + smbox = devm_kzalloc(dev, sizeof(*smbox), GFP_KERNEL); + if (!smbox) + return -ENOMEM; + + shmem = of_parse_phandle(cdev->of_node, "shmem", idx); + ret = of_address_to_resource(shmem, 0, &res); + of_node_put(shmem); + if (ret) { + dev_err(cdev, "failed to get SCMI %s shared memory\n", desc); + return ret; + } + + size = resource_size(&res); + smbox->shmem = devm_ioremap(dev, res.start, size); + if (!smbox->shmem) { + dev_err(dev, "failed to ioremap SCMI %s shared memory\n", desc); + return -EADDRNOTAVAIL; + } + + cl = &smbox->cl; + cl->dev = cdev; + cl->tx_prepare = tx ? tx_prepare : NULL; + cl->rx_callback = rx_callback; + cl->tx_block = false; + cl->knows_txdone = tx; + + smbox->chan = mbox_request_channel(cl, tx ? 0 : 1); + if (IS_ERR(smbox->chan)) { + ret = PTR_ERR(smbox->chan); + if (ret != -EPROBE_DEFER) + dev_err(cdev, "failed to request SCMI %s mailbox\n", + tx ? "Tx" : "Rx"); + return ret; + } + + cinfo->transport_info = smbox; + smbox->cinfo = cinfo; + + return 0; +} + +static int mailbox_chan_free(int id, void *p, void *data) +{ + struct scmi_chan_info *cinfo = p; + struct scmi_mailbox *smbox = cinfo->transport_info; + + if (!IS_ERR(smbox->chan)) { + mbox_free_channel(smbox->chan); + cinfo->transport_info = NULL; + smbox->chan = NULL; + smbox->cinfo = NULL; + } + + scmi_free_channel(cinfo, data, id); + + return 0; +} + +static int mailbox_send_message(struct scmi_chan_info *cinfo, + struct scmi_xfer *xfer) +{ + struct scmi_mailbox *smbox = cinfo->transport_info; + int ret; + + ret = mbox_send_message(smbox->chan, xfer); + + /* mbox_send_message returns non-negative value on success, so reset */ + if (ret > 0) + ret = 0; + + return ret; +} + +static void mailbox_mark_txdone(struct scmi_chan_info *cinfo, int ret) +{ + struct scmi_mailbox *smbox = cinfo->transport_info; + + /* + * NOTE: we might prefer not to need the mailbox ticker to manage the + * transfer queueing since the protocol layer queues things by itself. + * Unfortunately, we have to kick the mailbox framework after we have + * received our message. + */ + mbox_client_txdone(smbox->chan, ret); +} + +static void mailbox_fetch_response(struct scmi_chan_info *cinfo, + struct scmi_xfer *xfer) +{ + struct scmi_mailbox *smbox = cinfo->transport_info; + + shmem_fetch_response(smbox->shmem, xfer); +} + +static bool +mailbox_poll_done(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer) +{ + struct scmi_mailbox *smbox = cinfo->transport_info; + + return shmem_poll_done(smbox->shmem, xfer); +} + +static struct scmi_transport_ops scmi_mailbox_ops = { + .chan_available = mailbox_chan_available, + .chan_setup = mailbox_chan_setup, + .chan_free = mailbox_chan_free, + .send_message = mailbox_send_message, + .mark_txdone = mailbox_mark_txdone, + .fetch_response = mailbox_fetch_response, + .poll_done = mailbox_poll_done, +}; + +const struct scmi_desc scmi_mailbox_desc = { + .ops = &scmi_mailbox_ops, + .max_rx_timeout_ms = 30, /* We may increase this if required */ + .max_msg = 20, /* Limited by MBOX_TX_QUEUE_LEN */ + .max_msg_size = 128, +}; |