--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+
+/* Copyright (c) 2020, The Linux Foundation. All rights reserved. */
+/* Copyright (c) 2021-2024 Qualcomm Innovation Center, Inc. All rights reserved. */
+
+#include <linux/debugfs.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/mhi.h>
+#include <linux/mutex.h>
+#include <linux/overflow.h>
+#include <linux/pci.h>
+#include <linux/seq_file.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/workqueue.h>
+
+#include "qaic.h"
+#include "qaic_debugfs.h"
+
+#define BOOTLOG_POOL_SIZE 16
+#define BOOTLOG_MSG_SIZE 512
+
+struct bootlog_msg {
+ /* Buffer for bootlog messages */
+ char str[BOOTLOG_MSG_SIZE];
+ /* Root struct of device, used to access device resources */
+ struct qaic_device *qdev;
+ /* Work struct to schedule work coming on QAIC_LOGGING channel */
+ struct work_struct work;
+};
+
+struct bootlog_page {
+ /* Node in list of bootlog pages maintained by root device struct */
+ struct list_head node;
+ /* Total size of the buffer that holds the bootlogs. It is PAGE_SIZE */
+ unsigned int size;
+ /* Offset for the next bootlog */
+ unsigned int offset;
+};
+
+static int bootlog_show(struct seq_file *s, void *unused)
+{
+ struct bootlog_page *page;
+ struct qaic_device *qdev;
+ void *page_end;
+ void *log;
+
+ qdev = s->private;
+ mutex_lock(&qdev->bootlog_mutex);
+ list_for_each_entry(page, &qdev->bootlog, node) {
+ log = page + 1;
+ page_end = (void *)page + page->offset;
+ while (log < page_end) {
+ seq_printf(s, "%s", (char *)log);
+ log += strlen(log) + 1;
+ }
+ }
+ mutex_unlock(&qdev->bootlog_mutex);
+
+ return 0;
+}
+
+static int bootlog_fops_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, bootlog_show, inode->i_private);
+}
+
+static const struct file_operations bootlog_fops = {
+ .owner = THIS_MODULE,
+ .open = bootlog_fops_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+void qaic_debugfs_init(struct qaic_drm_device *qddev)
+{
+ struct qaic_device *qdev = qddev->qdev;
+ struct dentry *debugfs_root;
+
+ debugfs_root = to_drm(qddev)->debugfs_root;
+
+ debugfs_create_file("bootlog", 0400, debugfs_root, qdev, &bootlog_fops);
+}
+
+static struct bootlog_page *alloc_bootlog_page(struct qaic_device *qdev)
+{
+ struct bootlog_page *page;
+
+ page = (struct bootlog_page *)devm_get_free_pages(&qdev->pdev->dev, GFP_KERNEL, 0);
+ if (!page)
+ return page;
+
+ page->size = PAGE_SIZE;
+ page->offset = sizeof(*page);
+ list_add_tail(&page->node, &qdev->bootlog);
+
+ return page;
+}
+
+static int reset_bootlog(struct qaic_device *qdev)
+{
+ struct bootlog_page *page;
+ struct bootlog_page *i;
+
+ mutex_lock(&qdev->bootlog_mutex);
+ list_for_each_entry_safe(page, i, &qdev->bootlog, node) {
+ list_del(&page->node);
+ devm_free_pages(&qdev->pdev->dev, (unsigned long)page);
+ }
+
+ page = alloc_bootlog_page(qdev);
+ mutex_unlock(&qdev->bootlog_mutex);
+ if (!page)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void *bootlog_get_space(struct qaic_device *qdev, unsigned int size)
+{
+ struct bootlog_page *page;
+
+ page = list_last_entry(&qdev->bootlog, struct bootlog_page, node);
+
+ if (size_add(size, sizeof(*page)) > page->size)
+ return NULL;
+
+ if (page->offset + size > page->size) {
+ page = alloc_bootlog_page(qdev);
+ if (!page)
+ return NULL;
+ }
+
+ return (void *)page + page->offset;
+}
+
+static void bootlog_commit(struct qaic_device *qdev, unsigned int size)
+{
+ struct bootlog_page *page;
+
+ page = list_last_entry(&qdev->bootlog, struct bootlog_page, node);
+
+ page->offset += size;
+}
+
+static void bootlog_log(struct work_struct *work)
+{
+ struct bootlog_msg *msg = container_of(work, struct bootlog_msg, work);
+ unsigned int len = strlen(msg->str) + 1;
+ struct qaic_device *qdev = msg->qdev;
+ void *log;
+
+ mutex_lock(&qdev->bootlog_mutex);
+ log = bootlog_get_space(qdev, len);
+ if (log) {
+ memcpy(log, msg, len);
+ bootlog_commit(qdev, len);
+ }
+ mutex_unlock(&qdev->bootlog_mutex);
+
+ if (mhi_queue_buf(qdev->bootlog_ch, DMA_FROM_DEVICE, msg, BOOTLOG_MSG_SIZE, MHI_EOT))
+ devm_kfree(&qdev->pdev->dev, msg);
+}
+
+static int qaic_bootlog_mhi_probe(struct mhi_device *mhi_dev, const struct mhi_device_id *id)
+{
+ struct qaic_device *qdev = pci_get_drvdata(to_pci_dev(mhi_dev->mhi_cntrl->cntrl_dev));
+ struct bootlog_msg *msg;
+ int i, ret;
+
+ qdev->bootlog_wq = alloc_ordered_workqueue("qaic_bootlog", 0);
+ if (!qdev->bootlog_wq) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ ret = reset_bootlog(qdev);
+ if (ret)
+ goto destroy_workqueue;
+
+ ret = mhi_prepare_for_transfer(mhi_dev);
+ if (ret)
+ goto destroy_workqueue;
+
+ for (i = 0; i < BOOTLOG_POOL_SIZE; i++) {
+ msg = devm_kzalloc(&qdev->pdev->dev, sizeof(*msg), GFP_KERNEL);
+ if (!msg) {
+ ret = -ENOMEM;
+ goto mhi_unprepare;
+ }
+
+ msg->qdev = qdev;
+ INIT_WORK(&msg->work, bootlog_log);
+
+ ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, msg, BOOTLOG_MSG_SIZE, MHI_EOT);
+ if (ret)
+ goto mhi_unprepare;
+ }
+
+ dev_set_drvdata(&mhi_dev->dev, qdev);
+ qdev->bootlog_ch = mhi_dev;
+ return 0;
+
+mhi_unprepare:
+ mhi_unprepare_from_transfer(mhi_dev);
+destroy_workqueue:
+ flush_workqueue(qdev->bootlog_wq);
+ destroy_workqueue(qdev->bootlog_wq);
+out:
+ return ret;
+}
+
+static void qaic_bootlog_mhi_remove(struct mhi_device *mhi_dev)
+{
+ struct qaic_device *qdev;
+
+ qdev = dev_get_drvdata(&mhi_dev->dev);
+
+ mhi_unprepare_from_transfer(qdev->bootlog_ch);
+ flush_workqueue(qdev->bootlog_wq);
+ destroy_workqueue(qdev->bootlog_wq);
+ qdev->bootlog_ch = NULL;
+}
+
+static void qaic_bootlog_mhi_ul_xfer_cb(struct mhi_device *mhi_dev, struct mhi_result *mhi_result)
+{
+}
+
+static void qaic_bootlog_mhi_dl_xfer_cb(struct mhi_device *mhi_dev, struct mhi_result *mhi_result)
+{
+ struct qaic_device *qdev = dev_get_drvdata(&mhi_dev->dev);
+ struct bootlog_msg *msg = mhi_result->buf_addr;
+
+ if (mhi_result->transaction_status) {
+ devm_kfree(&qdev->pdev->dev, msg);
+ return;
+ }
+
+ /* Force a null at the end of the transferred string */
+ msg->str[mhi_result->bytes_xferd - 1] = 0;
+
+ queue_work(qdev->bootlog_wq, &msg->work);
+}
+
+static const struct mhi_device_id qaic_bootlog_mhi_match_table[] = {
+ { .chan = "QAIC_LOGGING", },
+ {},
+};
+
+static struct mhi_driver qaic_bootlog_mhi_driver = {
+ .id_table = qaic_bootlog_mhi_match_table,
+ .remove = qaic_bootlog_mhi_remove,
+ .probe = qaic_bootlog_mhi_probe,
+ .ul_xfer_cb = qaic_bootlog_mhi_ul_xfer_cb,
+ .dl_xfer_cb = qaic_bootlog_mhi_dl_xfer_cb,
+ .driver = {
+ .name = "qaic_bootlog",
+ },
+};
+
+int qaic_bootlog_register(void)
+{
+ return mhi_driver_register(&qaic_bootlog_mhi_driver);
+}
+
+void qaic_bootlog_unregister(void)
+{
+ mhi_driver_unregister(&qaic_bootlog_mhi_driver);
+}
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