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7adb2c8aaa
SMC/HVC can transmit only one message at the time as the shared memory
needs to be protected and the calls are synchronous.
However, in order to allow multiple threads to send SCMI messages
simultaneously, we need a larger poll of memory.
Let us just use value of 20 to keep it in sync mailbox transport
implementation. Any other value must work perfectly.
Link: https://lore.kernel.org/r/20201008143722.21888-4-etienne.carriere@linaro.org
Fixes: 1dc6558062 ("firmware: arm_scmi: Add smc/hvc transport")
Cc: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
[sudeep.holla: reworded the commit message to indicate the practicality]
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
154 lines
3.5 KiB
C
154 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* System Control and Management Interface (SCMI) Message SMC/HVC
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* Transport driver
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*
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* Copyright 2020 NXP
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*/
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#include <linux/arm-smccc.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/mutex.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/slab.h>
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#include "common.h"
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/**
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* struct scmi_smc - Structure representing a SCMI smc transport
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*
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* @cinfo: SCMI channel info
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* @shmem: Transmit/Receive shared memory area
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* @shmem_lock: Lock to protect access to Tx/Rx shared memory area
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* @func_id: smc/hvc call function id
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*/
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struct scmi_smc {
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struct scmi_chan_info *cinfo;
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struct scmi_shared_mem __iomem *shmem;
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struct mutex shmem_lock;
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u32 func_id;
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};
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static bool smc_chan_available(struct device *dev, int idx)
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{
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struct device_node *np = of_parse_phandle(dev->of_node, "shmem", 0);
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if (!np)
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return false;
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of_node_put(np);
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return true;
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}
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static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
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bool tx)
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{
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struct device *cdev = cinfo->dev;
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struct scmi_smc *scmi_info;
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resource_size_t size;
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struct resource res;
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struct device_node *np;
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u32 func_id;
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int ret;
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if (!tx)
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return -ENODEV;
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scmi_info = devm_kzalloc(dev, sizeof(*scmi_info), GFP_KERNEL);
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if (!scmi_info)
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return -ENOMEM;
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np = of_parse_phandle(cdev->of_node, "shmem", 0);
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ret = of_address_to_resource(np, 0, &res);
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of_node_put(np);
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if (ret) {
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dev_err(cdev, "failed to get SCMI Tx shared memory\n");
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return ret;
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}
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size = resource_size(&res);
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scmi_info->shmem = devm_ioremap(dev, res.start, size);
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if (!scmi_info->shmem) {
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dev_err(dev, "failed to ioremap SCMI Tx shared memory\n");
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return -EADDRNOTAVAIL;
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}
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ret = of_property_read_u32(dev->of_node, "arm,smc-id", &func_id);
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if (ret < 0)
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return ret;
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scmi_info->func_id = func_id;
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scmi_info->cinfo = cinfo;
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mutex_init(&scmi_info->shmem_lock);
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cinfo->transport_info = scmi_info;
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return 0;
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}
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static int smc_chan_free(int id, void *p, void *data)
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{
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struct scmi_chan_info *cinfo = p;
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struct scmi_smc *scmi_info = cinfo->transport_info;
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cinfo->transport_info = NULL;
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scmi_info->cinfo = NULL;
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scmi_free_channel(cinfo, data, id);
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return 0;
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}
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static int smc_send_message(struct scmi_chan_info *cinfo,
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struct scmi_xfer *xfer)
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{
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struct scmi_smc *scmi_info = cinfo->transport_info;
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struct arm_smccc_res res;
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mutex_lock(&scmi_info->shmem_lock);
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shmem_tx_prepare(scmi_info->shmem, xfer);
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arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
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scmi_rx_callback(scmi_info->cinfo, shmem_read_header(scmi_info->shmem));
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mutex_unlock(&scmi_info->shmem_lock);
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/* Only SMCCC_RET_NOT_SUPPORTED is valid error code */
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if (res.a0)
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return -EOPNOTSUPP;
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return 0;
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}
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static void smc_fetch_response(struct scmi_chan_info *cinfo,
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struct scmi_xfer *xfer)
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{
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struct scmi_smc *scmi_info = cinfo->transport_info;
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shmem_fetch_response(scmi_info->shmem, xfer);
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}
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static bool
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smc_poll_done(struct scmi_chan_info *cinfo, struct scmi_xfer *xfer)
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{
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struct scmi_smc *scmi_info = cinfo->transport_info;
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return shmem_poll_done(scmi_info->shmem, xfer);
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}
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static const struct scmi_transport_ops scmi_smc_ops = {
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.chan_available = smc_chan_available,
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.chan_setup = smc_chan_setup,
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.chan_free = smc_chan_free,
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.send_message = smc_send_message,
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.fetch_response = smc_fetch_response,
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.poll_done = smc_poll_done,
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};
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const struct scmi_desc scmi_smc_desc = {
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.ops = &scmi_smc_ops,
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.max_rx_timeout_ms = 30,
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.max_msg = 20,
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.max_msg_size = 128,
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};
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