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firmware: scmi: support Arm SMCCC transport

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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>
Reviewed-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Etienne Carriere
2020-09-09 18:44:02 +02:00
committed by Tom Rini
parent 240720e905
commit 1e35913a26
3 changed files with 93 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/firmware/scmi/Kconfig
View File

@@ -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.

1
drivers/firmware/scmi/Makefile
View File

@@ -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

89
drivers/firmware/scmi/smccc_agent.c Normal file
View File

@@ -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,
};