128 lines
2.8 KiB
C
128 lines
2.8 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright 2018-2020 Broadcom.
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*/
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#include "bcm_vk.h"
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#include "bcm_vk_msg.h"
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/*
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* allocate a ctx per file struct
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*/
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static struct bcm_vk_ctx *bcm_vk_get_ctx(struct bcm_vk *vk, const pid_t pid)
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{
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u32 i;
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struct bcm_vk_ctx *ctx = NULL;
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u32 hash_idx = hash_32(pid, VK_PID_HT_SHIFT_BIT);
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spin_lock(&vk->ctx_lock);
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for (i = 0; i < ARRAY_SIZE(vk->ctx); i++) {
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if (!vk->ctx[i].in_use) {
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vk->ctx[i].in_use = true;
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ctx = &vk->ctx[i];
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break;
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}
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}
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if (!ctx) {
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dev_err(&vk->pdev->dev, "All context in use\n");
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goto all_in_use_exit;
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}
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/* set the pid and insert it to hash table */
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ctx->pid = pid;
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ctx->hash_idx = hash_idx;
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list_add_tail(&ctx->node, &vk->pid_ht[hash_idx].head);
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/* increase kref */
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kref_get(&vk->kref);
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all_in_use_exit:
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spin_unlock(&vk->ctx_lock);
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return ctx;
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}
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static int bcm_vk_free_ctx(struct bcm_vk *vk, struct bcm_vk_ctx *ctx)
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{
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u32 idx;
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u32 hash_idx;
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pid_t pid;
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struct bcm_vk_ctx *entry;
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int count = 0;
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if (!ctx) {
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dev_err(&vk->pdev->dev, "NULL context detected\n");
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return -EINVAL;
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}
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idx = ctx->idx;
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pid = ctx->pid;
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spin_lock(&vk->ctx_lock);
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if (!vk->ctx[idx].in_use) {
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dev_err(&vk->pdev->dev, "context[%d] not in use!\n", idx);
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} else {
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vk->ctx[idx].in_use = false;
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vk->ctx[idx].miscdev = NULL;
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/* Remove it from hash list and see if it is the last one. */
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list_del(&ctx->node);
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hash_idx = ctx->hash_idx;
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list_for_each_entry(entry, &vk->pid_ht[hash_idx].head, node) {
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if (entry->pid == pid)
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count++;
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}
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}
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spin_unlock(&vk->ctx_lock);
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return count;
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}
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int bcm_vk_open(struct inode *inode, struct file *p_file)
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{
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struct bcm_vk_ctx *ctx;
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struct miscdevice *miscdev = (struct miscdevice *)p_file->private_data;
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struct bcm_vk *vk = container_of(miscdev, struct bcm_vk, miscdev);
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struct device *dev = &vk->pdev->dev;
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int rc = 0;
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/* get a context and set it up for file */
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ctx = bcm_vk_get_ctx(vk, task_tgid_nr(current));
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if (!ctx) {
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dev_err(dev, "Error allocating context\n");
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rc = -ENOMEM;
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} else {
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/*
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* set up context and replace private data with context for
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* other methods to use. Reason for the context is because
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* it is allowed for multiple sessions to open the sysfs, and
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* for each file open, when upper layer query the response,
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* only those that are tied to a specific open should be
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* returned. The context->idx will be used for such binding
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*/
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ctx->miscdev = miscdev;
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p_file->private_data = ctx;
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dev_dbg(dev, "ctx_returned with idx %d, pid %d\n",
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ctx->idx, ctx->pid);
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}
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return rc;
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}
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int bcm_vk_release(struct inode *inode, struct file *p_file)
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{
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int ret;
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struct bcm_vk_ctx *ctx = p_file->private_data;
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struct bcm_vk *vk = container_of(ctx->miscdev, struct bcm_vk, miscdev);
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ret = bcm_vk_free_ctx(vk, ctx);
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kref_put(&vk->kref, bcm_vk_release_data);
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return ret;
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}
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