247 lines
7.0 KiB
C
247 lines
7.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2010,2015,2019 The Linux Foundation. All rights reserved.
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* Copyright (C) 2015 Linaro Ltd.
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*/
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#include <linux/slab.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/errno.h>
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#include <linux/err.h>
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#include <linux/firmware/qcom/qcom_scm.h>
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#include <linux/arm-smccc.h>
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#include <linux/dma-mapping.h>
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#include "qcom_scm.h"
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static DEFINE_MUTEX(qcom_scm_lock);
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/**
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* struct arm_smccc_args
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* @args: The array of values used in registers in smc instruction
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*/
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struct arm_smccc_args {
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unsigned long args[8];
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};
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/**
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* struct scm_legacy_command - one SCM command buffer
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* @len: total available memory for command and response
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* @buf_offset: start of command buffer
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* @resp_hdr_offset: start of response buffer
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* @id: command to be executed
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* @buf: buffer returned from scm_legacy_get_command_buffer()
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*
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* An SCM command is laid out in memory as follows:
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*
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* ------------------- <--- struct scm_legacy_command
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* | command header |
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* ------------------- <--- scm_legacy_get_command_buffer()
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* | command buffer |
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* ------------------- <--- struct scm_legacy_response and
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* | response header | scm_legacy_command_to_response()
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* ------------------- <--- scm_legacy_get_response_buffer()
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* | response buffer |
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* -------------------
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*
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* There can be arbitrary padding between the headers and buffers so
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* you should always use the appropriate scm_legacy_get_*_buffer() routines
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* to access the buffers in a safe manner.
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*/
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struct scm_legacy_command {
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__le32 len;
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__le32 buf_offset;
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__le32 resp_hdr_offset;
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__le32 id;
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__le32 buf[];
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};
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/**
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* struct scm_legacy_response - one SCM response buffer
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* @len: total available memory for response
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* @buf_offset: start of response data relative to start of scm_legacy_response
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* @is_complete: indicates if the command has finished processing
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*/
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struct scm_legacy_response {
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__le32 len;
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__le32 buf_offset;
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__le32 is_complete;
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};
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/**
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* scm_legacy_command_to_response() - Get a pointer to a scm_legacy_response
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* @cmd: command
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*
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* Returns a pointer to a response for a command.
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*/
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static inline struct scm_legacy_response *scm_legacy_command_to_response(
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const struct scm_legacy_command *cmd)
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{
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return (void *)cmd + le32_to_cpu(cmd->resp_hdr_offset);
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}
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/**
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* scm_legacy_get_command_buffer() - Get a pointer to a command buffer
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* @cmd: command
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*
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* Returns a pointer to the command buffer of a command.
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*/
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static inline void *scm_legacy_get_command_buffer(
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const struct scm_legacy_command *cmd)
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{
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return (void *)cmd->buf;
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}
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/**
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* scm_legacy_get_response_buffer() - Get a pointer to a response buffer
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* @rsp: response
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*
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* Returns a pointer to a response buffer of a response.
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*/
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static inline void *scm_legacy_get_response_buffer(
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const struct scm_legacy_response *rsp)
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{
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return (void *)rsp + le32_to_cpu(rsp->buf_offset);
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}
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static void __scm_legacy_do(const struct arm_smccc_args *smc,
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struct arm_smccc_res *res)
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{
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do {
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arm_smccc_smc(smc->args[0], smc->args[1], smc->args[2],
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smc->args[3], smc->args[4], smc->args[5],
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smc->args[6], smc->args[7], res);
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} while (res->a0 == QCOM_SCM_INTERRUPTED);
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}
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/**
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* scm_legacy_call() - Sends a command to the SCM and waits for the command to
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* finish processing.
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* @dev: device
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* @desc: descriptor structure containing arguments and return values
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* @res: results from SMC call
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*
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* A note on cache maintenance:
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* Note that any buffers that are expected to be accessed by the secure world
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* must be flushed before invoking qcom_scm_call and invalidated in the cache
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* immediately after qcom_scm_call returns. Cache maintenance on the command
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* and response buffers is taken care of by qcom_scm_call; however, callers are
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* responsible for any other cached buffers passed over to the secure world.
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*/
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int scm_legacy_call(struct device *dev, const struct qcom_scm_desc *desc,
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struct qcom_scm_res *res)
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{
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u8 arglen = desc->arginfo & 0xf;
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int ret = 0, context_id;
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unsigned int i;
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struct scm_legacy_command *cmd;
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struct scm_legacy_response *rsp;
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struct arm_smccc_args smc = {0};
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struct arm_smccc_res smc_res;
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const size_t cmd_len = arglen * sizeof(__le32);
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const size_t resp_len = MAX_QCOM_SCM_RETS * sizeof(__le32);
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size_t alloc_len = sizeof(*cmd) + cmd_len + sizeof(*rsp) + resp_len;
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dma_addr_t cmd_phys;
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__le32 *arg_buf;
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const __le32 *res_buf;
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cmd = kzalloc(PAGE_ALIGN(alloc_len), GFP_KERNEL);
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if (!cmd)
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return -ENOMEM;
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cmd->len = cpu_to_le32(alloc_len);
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cmd->buf_offset = cpu_to_le32(sizeof(*cmd));
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cmd->resp_hdr_offset = cpu_to_le32(sizeof(*cmd) + cmd_len);
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cmd->id = cpu_to_le32(SCM_LEGACY_FNID(desc->svc, desc->cmd));
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arg_buf = scm_legacy_get_command_buffer(cmd);
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for (i = 0; i < arglen; i++)
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arg_buf[i] = cpu_to_le32(desc->args[i]);
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rsp = scm_legacy_command_to_response(cmd);
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cmd_phys = dma_map_single(dev, cmd, alloc_len, DMA_TO_DEVICE);
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if (dma_mapping_error(dev, cmd_phys)) {
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kfree(cmd);
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return -ENOMEM;
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}
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smc.args[0] = 1;
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smc.args[1] = (unsigned long)&context_id;
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smc.args[2] = cmd_phys;
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mutex_lock(&qcom_scm_lock);
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__scm_legacy_do(&smc, &smc_res);
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if (smc_res.a0)
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ret = qcom_scm_remap_error(smc_res.a0);
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mutex_unlock(&qcom_scm_lock);
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if (ret)
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goto out;
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do {
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dma_sync_single_for_cpu(dev, cmd_phys + sizeof(*cmd) + cmd_len,
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sizeof(*rsp), DMA_FROM_DEVICE);
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} while (!rsp->is_complete);
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dma_sync_single_for_cpu(dev, cmd_phys + sizeof(*cmd) + cmd_len +
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le32_to_cpu(rsp->buf_offset),
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resp_len, DMA_FROM_DEVICE);
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if (res) {
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res_buf = scm_legacy_get_response_buffer(rsp);
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for (i = 0; i < MAX_QCOM_SCM_RETS; i++)
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res->result[i] = le32_to_cpu(res_buf[i]);
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}
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out:
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dma_unmap_single(dev, cmd_phys, alloc_len, DMA_TO_DEVICE);
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kfree(cmd);
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return ret;
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}
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#define SCM_LEGACY_ATOMIC_N_REG_ARGS 5
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#define SCM_LEGACY_ATOMIC_FIRST_REG_IDX 2
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#define SCM_LEGACY_CLASS_REGISTER (0x2 << 8)
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#define SCM_LEGACY_MASK_IRQS BIT(5)
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#define SCM_LEGACY_ATOMIC_ID(svc, cmd, n) \
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((SCM_LEGACY_FNID(svc, cmd) << 12) | \
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SCM_LEGACY_CLASS_REGISTER | \
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SCM_LEGACY_MASK_IRQS | \
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(n & 0xf))
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/**
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* scm_legacy_call_atomic() - Send an atomic SCM command with up to 5 arguments
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* and 3 return values
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* @unused: device, legacy argument, not used, can be NULL
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* @desc: SCM call descriptor containing arguments
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* @res: SCM call return values
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*
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* This shall only be used with commands that are guaranteed to be
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* uninterruptable, atomic and SMP safe.
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*/
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int scm_legacy_call_atomic(struct device *unused,
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const struct qcom_scm_desc *desc,
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struct qcom_scm_res *res)
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{
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int context_id;
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struct arm_smccc_res smc_res;
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size_t arglen = desc->arginfo & 0xf;
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BUG_ON(arglen > SCM_LEGACY_ATOMIC_N_REG_ARGS);
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arm_smccc_smc(SCM_LEGACY_ATOMIC_ID(desc->svc, desc->cmd, arglen),
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(unsigned long)&context_id,
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desc->args[0], desc->args[1], desc->args[2],
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desc->args[3], desc->args[4], 0, &smc_res);
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if (res) {
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res->result[0] = smc_res.a1;
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res->result[1] = smc_res.a2;
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res->result[2] = smc_res.a3;
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}
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return smc_res.a0;
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}
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