// SPDX-License-Identifier: GPL-2.0-only /* Copyright (c) 2010,2015,2019 The Linux Foundation. All rights reserved. * Copyright (C) 2015 Linaro Ltd. */ #include <linux/slab.h> #include <linux/io.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/errno.h> #include <linux/err.h> #include <linux/qcom_scm.h> #include <linux/arm-smccc.h> #include <linux/dma-mapping.h> #include "qcom_scm.h" static DEFINE_MUTEX(qcom_scm_lock); /** * struct arm_smccc_args * @args: The array of values used in registers in smc instruction */ struct arm_smccc_args { unsigned long args[8]; }; /** * struct scm_legacy_command - one SCM command buffer * @len: total available memory for command and response * @buf_offset: start of command buffer * @resp_hdr_offset: start of response buffer * @id: command to be executed * @buf: buffer returned from scm_legacy_get_command_buffer() * * An SCM command is laid out in memory as follows: * * ------------------- <--- struct scm_legacy_command * | command header | * ------------------- <--- scm_legacy_get_command_buffer() * | command buffer | * ------------------- <--- struct scm_legacy_response and * | response header | scm_legacy_command_to_response() * ------------------- <--- scm_legacy_get_response_buffer() * | response buffer | * ------------------- * * There can be arbitrary padding between the headers and buffers so * you should always use the appropriate scm_legacy_get_*_buffer() routines * to access the buffers in a safe manner. */ struct scm_legacy_command { __le32 len; __le32 buf_offset; __le32 resp_hdr_offset; __le32 id; __le32 buf[]; }; /** * struct scm_legacy_response - one SCM response buffer * @len: total available memory for response * @buf_offset: start of response data relative to start of scm_legacy_response * @is_complete: indicates if the command has finished processing */ struct scm_legacy_response { __le32 len; __le32 buf_offset; __le32 is_complete; }; /** * scm_legacy_command_to_response() - Get a pointer to a scm_legacy_response * @cmd: command * * Returns a pointer to a response for a command. */ static inline struct scm_legacy_response *scm_legacy_command_to_response( const struct scm_legacy_command *cmd) { return (void *)cmd + le32_to_cpu(cmd->resp_hdr_offset); } /** * scm_legacy_get_command_buffer() - Get a pointer to a command buffer * @cmd: command * * Returns a pointer to the command buffer of a command. */ static inline void *scm_legacy_get_command_buffer( const struct scm_legacy_command *cmd) { return (void *)cmd->buf; } /** * scm_legacy_get_response_buffer() - Get a pointer to a response buffer * @rsp: response * * Returns a pointer to a response buffer of a response. */ static inline void *scm_legacy_get_response_buffer( const struct scm_legacy_response *rsp) { return (void *)rsp + le32_to_cpu(rsp->buf_offset); } static void __scm_legacy_do(const struct arm_smccc_args *smc, struct arm_smccc_res *res) { do { arm_smccc_smc(smc->args[0], smc->args[1], smc->args[2], smc->args[3], smc->args[4], smc->args[5], smc->args[6], smc->args[7], res); } while (res->a0 == QCOM_SCM_INTERRUPTED); } /** * qcom_scm_call() - Sends a command to the SCM and waits for the command to * finish processing. * * A note on cache maintenance: * Note that any buffers that are expected to be accessed by the secure world * must be flushed before invoking qcom_scm_call and invalidated in the cache * immediately after qcom_scm_call returns. Cache maintenance on the command * and response buffers is taken care of by qcom_scm_call; however, callers are * responsible for any other cached buffers passed over to the secure world. */ int scm_legacy_call(struct device *dev, const struct qcom_scm_desc *desc, struct qcom_scm_res *res) { u8 arglen = desc->arginfo & 0xf; int ret = 0, context_id; unsigned int i; struct scm_legacy_command *cmd; struct scm_legacy_response *rsp; struct arm_smccc_args smc = {0}; struct arm_smccc_res smc_res; const size_t cmd_len = arglen * sizeof(__le32); const size_t resp_len = MAX_QCOM_SCM_RETS * sizeof(__le32); size_t alloc_len = sizeof(*cmd) + cmd_len + sizeof(*rsp) + resp_len; dma_addr_t cmd_phys; __le32 *arg_buf; const __le32 *res_buf; cmd = kzalloc(PAGE_ALIGN(alloc_len), GFP_KERNEL); if (!cmd) return -ENOMEM; cmd->len = cpu_to_le32(alloc_len); cmd->buf_offset = cpu_to_le32(sizeof(*cmd)); cmd->resp_hdr_offset = cpu_to_le32(sizeof(*cmd) + cmd_len); cmd->id = cpu_to_le32(SCM_LEGACY_FNID(desc->svc, desc->cmd)); arg_buf = scm_legacy_get_command_buffer(cmd); for (i = 0; i < arglen; i++) arg_buf[i] = cpu_to_le32(desc->args[i]); rsp = scm_legacy_command_to_response(cmd); cmd_phys = dma_map_single(dev, cmd, alloc_len, DMA_TO_DEVICE); if (dma_mapping_error(dev, cmd_phys)) { kfree(cmd); return -ENOMEM; } smc.args[0] = 1; smc.args[1] = (unsigned long)&context_id; smc.args[2] = cmd_phys; mutex_lock(&qcom_scm_lock); __scm_legacy_do(&smc, &smc_res); if (smc_res.a0) ret = qcom_scm_remap_error(smc_res.a0); mutex_unlock(&qcom_scm_lock); if (ret) goto out; do { dma_sync_single_for_cpu(dev, cmd_phys + sizeof(*cmd) + cmd_len, sizeof(*rsp), DMA_FROM_DEVICE); } while (!rsp->is_complete); dma_sync_single_for_cpu(dev, cmd_phys + sizeof(*cmd) + cmd_len + le32_to_cpu(rsp->buf_offset), resp_len, DMA_FROM_DEVICE); if (res) { res_buf = scm_legacy_get_response_buffer(rsp); for (i = 0; i < MAX_QCOM_SCM_RETS; i++) res->result[i] = le32_to_cpu(res_buf[i]); } out: dma_unmap_single(dev, cmd_phys, alloc_len, DMA_TO_DEVICE); kfree(cmd); return ret; } #define SCM_LEGACY_ATOMIC_N_REG_ARGS 5 #define SCM_LEGACY_ATOMIC_FIRST_REG_IDX 2 #define SCM_LEGACY_CLASS_REGISTER (0x2 << 8) #define SCM_LEGACY_MASK_IRQS BIT(5) #define SCM_LEGACY_ATOMIC_ID(svc, cmd, n) \ ((SCM_LEGACY_FNID(svc, cmd) << 12) | \ SCM_LEGACY_CLASS_REGISTER | \ SCM_LEGACY_MASK_IRQS | \ (n & 0xf)) /** * qcom_scm_call_atomic() - Send an atomic SCM command with up to 5 arguments * and 3 return values * @desc: SCM call descriptor containing arguments * @res: SCM call return values * * This shall only be used with commands that are guaranteed to be * uninterruptable, atomic and SMP safe. */ int scm_legacy_call_atomic(struct device *unused, const struct qcom_scm_desc *desc, struct qcom_scm_res *res) { int context_id; struct arm_smccc_res smc_res; size_t arglen = desc->arginfo & 0xf; BUG_ON(arglen > SCM_LEGACY_ATOMIC_N_REG_ARGS); arm_smccc_smc(SCM_LEGACY_ATOMIC_ID(desc->svc, desc->cmd, arglen), (unsigned long)&context_id, desc->args[0], desc->args[1], desc->args[2], desc->args[3], desc->args[4], 0, &smc_res); if (res) { res->result[0] = smc_res.a1; res->result[1] = smc_res.a2; res->result[2] = smc_res.a3; } return smc_res.a0; }