// SPDX-License-Identifier: GPL-2.0 /* * System Control and Management Interface (SCMI) Message Mailbox Transport * driver. * * Copyright (C) 2019 ARM Ltd. */ #include #include #include #include #include #include #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, smbox->cinfo); } 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), NULL); } 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_validate(struct device *cdev) { int num_mb, num_sh, ret = 0; struct device_node *np = cdev->of_node; num_mb = of_count_phandle_with_args(np, "mboxes", "#mbox-cells"); num_sh = of_count_phandle_with_args(np, "shmem", NULL); /* Bail out if mboxes and shmem descriptors are inconsistent */ if (num_mb <= 0 || num_sh > 2 || num_mb != num_sh) { dev_warn(cdev, "Invalid channel descriptor for '%s'\n", of_node_full_name(np)); return -EINVAL; } if (num_sh > 1) { struct device_node *np_tx, *np_rx; np_tx = of_parse_phandle(np, "shmem", 0); np_rx = of_parse_phandle(np, "shmem", 1); /* SCMI Tx and Rx shared mem areas have to be distinct */ if (!np_tx || !np_rx || np_tx == np_rx) { dev_warn(cdev, "Invalid shmem descriptor for '%s'\n", of_node_full_name(np)); ret = -EINVAL; } of_node_put(np_tx); of_node_put(np_rx); } return ret; } 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; ret = mailbox_chan_validate(cdev); if (ret) return ret; smbox = devm_kzalloc(dev, sizeof(*smbox), GFP_KERNEL); if (!smbox) return -ENOMEM; shmem = of_parse_phandle(cdev->of_node, "shmem", idx); if (!of_device_is_compatible(shmem, "arm,scmi-shmem")) { of_node_put(shmem); return -ENXIO; } 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 (smbox && !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_xfer *__unused) { 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 void mailbox_fetch_notification(struct scmi_chan_info *cinfo, size_t max_len, struct scmi_xfer *xfer) { struct scmi_mailbox *smbox = cinfo->transport_info; shmem_fetch_notification(smbox->shmem, max_len, xfer); } static void mailbox_clear_channel(struct scmi_chan_info *cinfo) { struct scmi_mailbox *smbox = cinfo->transport_info; shmem_clear_channel(smbox->shmem); } 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 const 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, .fetch_notification = mailbox_fetch_notification, .clear_channel = mailbox_clear_channel, .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, };