This change implements a SMCCC transport for SCMI exchanges. This implementation follows the Linux kernel as references implementation for SCMI message processing, using the SMT format for communication channel meta-data.
Use of SMCCC transport in SCMI FDT bindings are defined in the Linux kernel DT bindings since v5.8. SMCCC with SMT is implemented in OP-TEE from tag 3.9.0 [2].
Links: [2] https://github.com/OP-TEE/optee_os/commit/a58c4d706d23 Signed-off-by: Etienne Carriere etienne.carriere@linaro.org Cc: Simon Glass sjg@chromium.org Cc: Peng Fan peng.fan@nxp.com Cc: Sudeep Holla sudeep.holla@arm.com ---
Changes in v4: - Update CONFIG_SCMI_FIRMWARE dependencies regarding CONFIG_ARM_SMCCC. - Remove useless cast hence remove helper dev2agent() to get dev private. - Fix header file inclusion ordering.
Changes in v3: - This is a followup of the SCMI agent patches posted in https://patchwork.ozlabs.org/project/uboot/list/?series=196253 The v3 splits commits and introduces a new uclass as requested. - This patch implements the same Arm SMCCC SCMI agent as presented in v2 but in its own source file smccc_agent.c, and based in smt.h. --- drivers/firmware/scmi/Kconfig | 6 +- drivers/firmware/scmi/Makefile | 1 + drivers/firmware/scmi/smccc_agent.c | 89 +++++++++++++++++++++++++++++ 3 files changed, 93 insertions(+), 3 deletions(-) create mode 100644 drivers/firmware/scmi/smccc_agent.c
diff --git a/drivers/firmware/scmi/Kconfig b/drivers/firmware/scmi/Kconfig index c501bf4943..c3a109beac 100644 --- a/drivers/firmware/scmi/Kconfig +++ b/drivers/firmware/scmi/Kconfig @@ -2,7 +2,7 @@ config SCMI_FIRMWARE bool "Enable SCMI support" select FIRMWARE select OF_TRANSLATE - depends on SANDBOX || DM_MAILBOX + depends on SANDBOX || DM_MAILBOX || ARM_SMCCC help System Control and Management Interface (SCMI) is a communication protocol that defines standard interfaces for power, performance @@ -15,5 +15,5 @@ config SCMI_FIRMWARE
Communications between agent (client) and the SCMI server are based on message exchange. Messages can be exchange over tranport - channels as a mailbox device with some piece of identified shared - memory. + channels as a mailbox device or an Arm SMCCC service with some + piece of identified shared memory. diff --git a/drivers/firmware/scmi/Makefile b/drivers/firmware/scmi/Makefile index d22f53efe7..2f782bbd55 100644 --- a/drivers/firmware/scmi/Makefile +++ b/drivers/firmware/scmi/Makefile @@ -1,4 +1,5 @@ obj-y += scmi_agent-uclass.o obj-y += smt.o +obj-$(CONFIG_ARM_SMCCC) += smccc_agent.o obj-$(CONFIG_DM_MAILBOX) += mailbox_agent.o obj-$(CONFIG_SANDBOX) += sandbox-scmi_agent.o diff --git a/drivers/firmware/scmi/smccc_agent.c b/drivers/firmware/scmi/smccc_agent.c new file mode 100644 index 0000000000..85dbf9195e --- /dev/null +++ b/drivers/firmware/scmi/smccc_agent.c @@ -0,0 +1,89 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2020 Linaro Limited. + */ + +#include <common.h> +#include <dm.h> +#include <errno.h> +#include <scmi_agent.h> +#include <scmi_agent-uclass.h> +#include <dm/devres.h> +#include <dm/device-internal.h> +#include <linux/arm-smccc.h> +#include <linux/compat.h> + +#include "smt.h" + +#define SMCCC_RET_NOT_SUPPORTED ((unsigned long)-1) + +/** + * struct scmi_smccc_channel - Description of an SCMI SMCCC transport + * @func_id: SMCCC function ID used by the SCMI transport + * @smt: Shared memory buffer + */ +struct scmi_smccc_channel { + ulong func_id; + struct scmi_smt smt; +}; + +static int scmi_smccc_process_msg(struct udevice *dev, struct scmi_msg *msg) +{ + struct scmi_smccc_channel *chan = dev_get_priv(dev); + struct arm_smccc_res res; + int ret; + + ret = scmi_write_msg_to_smt(dev, &chan->smt, msg); + if (ret) + return ret; + + arm_smccc_smc(chan->func_id, 0, 0, 0, 0, 0, 0, 0, &res); + if (res.a0 == SMCCC_RET_NOT_SUPPORTED) + ret = -ENXIO; + else + ret = scmi_read_resp_from_smt(dev, &chan->smt, msg); + + scmi_clear_smt_channel(&chan->smt); + + return ret; +} + +static int scmi_smccc_probe(struct udevice *dev) +{ + struct scmi_smccc_channel *chan = dev_get_priv(dev); + u32 func_id; + int ret; + + if (dev_read_u32(dev, "arm,smc-id", &func_id)) { + dev_err(dev, "Missing property func-id\n"); + return -EINVAL; + } + + chan->func_id = func_id; + + ret = scmi_dt_get_smt_buffer(dev, &chan->smt); + if (ret) { + dev_err(dev, "Failed to get smt resources: %d\n", ret); + return ret; + } + + return 0; +} + +static const struct udevice_id scmi_smccc_ids[] = { + { .compatible = "arm,scmi-smc" }, + { } +}; + +static const struct scmi_agent_ops scmi_smccc_ops = { + .process_msg = scmi_smccc_process_msg, +}; + +U_BOOT_DRIVER(scmi_smccc) = { + .name = "scmi-over-smccc", + .id = UCLASS_SCMI_AGENT, + .of_match = scmi_smccc_ids, + .priv_auto_alloc_size = sizeof(struct scmi_smccc_channel), + .probe = scmi_smccc_probe, + .ops = &scmi_smccc_ops, +};