From 240720e9052fa7459e4d8a46d508db1ae41ed238 Mon Sep 17 00:00:00 2001 From: Etienne Carriere Date: Wed, 9 Sep 2020 18:44:01 +0200 Subject: firmware: scmi: mailbox/smt agent device This change implements a mailbox transport using SMT format for SCMI exchanges. This implementation follows the Linux kernel and SCP-firmware [1] as references implementation for SCMI message processing using SMT format for communication channel meta-data. Use of mailboxes in SCMI FDT bindings are defined in the Linux kernel DT bindings since v4.17. Links: [1] https://github.com/ARM-software/SCP-firmware Signed-off-by: Etienne Carriere Cc: Simon Glass Cc: Peng Fan Cc: Sudeep Holla Reviewed-by: Simon Glass --- drivers/firmware/scmi/smt.c | 139 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 139 insertions(+) create mode 100644 drivers/firmware/scmi/smt.c (limited to 'drivers/firmware/scmi/smt.c') diff --git a/drivers/firmware/scmi/smt.c b/drivers/firmware/scmi/smt.c new file mode 100644 index 0000000..ce8fe49 --- /dev/null +++ b/drivers/firmware/scmi/smt.c @@ -0,0 +1,139 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2015-2019, Arm Limited and Contributors. All rights reserved. + * Copyright (C) 2019-2020 Linaro Limited. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "smt.h" + +/** + * Get shared memory configuration defined by the referred DT phandle + * Return with a errno compliant value. + */ +int scmi_dt_get_smt_buffer(struct udevice *dev, struct scmi_smt *smt) +{ + int ret; + struct ofnode_phandle_args args; + struct resource resource; + fdt32_t faddr; + phys_addr_t paddr; + + ret = dev_read_phandle_with_args(dev, "shmem", NULL, 0, 0, &args); + if (ret) + return ret; + + ret = ofnode_read_resource(args.node, 0, &resource); + if (ret) + return ret; + + faddr = cpu_to_fdt32(resource.start); + paddr = ofnode_translate_address(args.node, &faddr); + + smt->size = resource_size(&resource); + if (smt->size < sizeof(struct scmi_smt_header)) { + dev_err(dev, "Shared memory buffer too small\n"); + return -EINVAL; + } + + smt->buf = devm_ioremap(dev, paddr, smt->size); + if (!smt->buf) + return -ENOMEM; + +#ifdef CONFIG_ARM + if (dcache_status()) + mmu_set_region_dcache_behaviour((uintptr_t)smt->buf, + smt->size, DCACHE_OFF); +#endif + + return 0; +} + +/** + * Write SCMI message @msg into a SMT shared buffer @smt. + * Return 0 on success and with a negative errno in case of error. + */ +int scmi_write_msg_to_smt(struct udevice *dev, struct scmi_smt *smt, + struct scmi_msg *msg) +{ + struct scmi_smt_header *hdr = (void *)smt->buf; + + if ((!msg->in_msg && msg->in_msg_sz) || + (!msg->out_msg && msg->out_msg_sz)) + return -EINVAL; + + if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) { + dev_dbg(dev, "Channel busy\n"); + return -EBUSY; + } + + if (smt->size < (sizeof(*hdr) + msg->in_msg_sz) || + smt->size < (sizeof(*hdr) + msg->out_msg_sz)) { + dev_dbg(dev, "Buffer too small\n"); + return -ETOOSMALL; + } + + /* Load message in shared memory */ + hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE; + hdr->length = msg->in_msg_sz + sizeof(hdr->msg_header); + hdr->msg_header = SMT_HEADER_TOKEN(0) | + SMT_HEADER_MESSAGE_TYPE(0) | + SMT_HEADER_PROTOCOL_ID(msg->protocol_id) | + SMT_HEADER_MESSAGE_ID(msg->message_id); + + memcpy_toio(hdr->msg_payload, msg->in_msg, msg->in_msg_sz); + + return 0; +} + +/** + * Read SCMI message from a SMT shared buffer @smt and copy it into @msg. + * Return 0 on success and with a negative errno in case of error. + */ +int scmi_read_resp_from_smt(struct udevice *dev, struct scmi_smt *smt, + struct scmi_msg *msg) +{ + struct scmi_smt_header *hdr = (void *)smt->buf; + + if (!(hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE)) { + dev_err(dev, "Channel unexpectedly busy\n"); + return -EBUSY; + } + + if (hdr->channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR) { + dev_err(dev, "Channel error reported, reset channel\n"); + return -ECOMM; + } + + if (hdr->length > msg->out_msg_sz + sizeof(hdr->msg_header)) { + dev_err(dev, "Buffer to small\n"); + return -ETOOSMALL; + } + + /* Get the data */ + msg->out_msg_sz = hdr->length - sizeof(hdr->msg_header); + memcpy_fromio(msg->out_msg, hdr->msg_payload, msg->out_msg_sz); + + return 0; +} + +/** + * Clear SMT flags in shared buffer to allow further message exchange + */ +void scmi_clear_smt_channel(struct scmi_smt *smt) +{ + struct scmi_smt_header *hdr = (void *)smt->buf; + + hdr->channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_ERROR; +} -- cgit v1.1