/*
* Copyright 2016 Broadcom
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation (the "GPL").
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 (GPLv2) for more details.
*
* You should have received a copy of the GNU General Public License
* version 2 (GPLv2) along with this source code.
*/
/*
* Broadcom PDC Mailbox Driver
* The PDC provides a ring based programming interface to one or more hardware
* offload engines. For example, the PDC driver works with both SPU-M and SPU2
* cryptographic offload hardware. In some chips the PDC is referred to as MDE,
* and in others the FA2/FA+ hardware is used with this PDC driver.
*
* The PDC driver registers with the Linux mailbox framework as a mailbox
* controller, once for each PDC instance. Ring 0 for each PDC is registered as
* a mailbox channel. The PDC driver uses interrupts to determine when data
* transfers to and from an offload engine are complete. The PDC driver uses
* threaded IRQs so that response messages are handled outside of interrupt
* context.
*
* The PDC driver allows multiple messages to be pending in the descriptor
* rings. The tx_msg_start descriptor index indicates where the last message
* starts. The txin_numd value at this index indicates how many descriptor
* indexes make up the message. Similar state is kept on the receive side. When
* an rx interrupt indicates a response is ready, the PDC driver processes numd
* descriptors from the tx and rx ring, thus processing one response at a time.
*/
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/debugfs.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/mailbox_controller.h>
#include <linux/mailbox/brcm-message.h>
#include <linux/scatterlist.h>
#include <linux/dma-direction.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#define PDC_SUCCESS 0
#define RING_ENTRY_SIZE sizeof(struct dma64dd)
/* # entries in PDC dma ring */
#define PDC_RING_ENTRIES 512
/*
* Minimum number of ring des
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