path: root/drivers/staging/most/dim2/dim2.c

// SPDX-License-Identifier: GPL-2.0
/*
 * dim2.c - MediaLB DIM2 Hardware Dependent Module
 *
 * Copyright (C) 2015-2016, Microchip Technology Germany II GmbH & Co. KG
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/printk.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/sched.h>
#include <linux/kthread.h>
#include <linux/most.h>
#include <linux/of.h>
#include "hal.h"
#include "errors.h"
#include "sysfs.h"

#define DMA_CHANNELS (32 - 1)  /* channel 0 is a system channel */

#define MAX_BUFFERS_PACKET      32
#define MAX_BUFFERS_STREAMING   32
#define MAX_BUF_SIZE_PACKET     2048
#define MAX_BUF_SIZE_STREAMING  (8 * 1024)

/*
 * The parameter representing the number of frames per sub-buffer for
 * synchronous channels.  Valid values: [0 .. 6].
 *
 * The values 0, 1, 2, 3, 4, 5, 6 represent corresponding number of frames per
 * sub-buffer 1, 2, 4, 8, 16, 32, 64.
 */
static u8 fcnt = 4;  /* (1 << fcnt) frames per subbuffer */
module_param(fcnt, byte, 0000);
MODULE_PARM_DESC(fcnt, "Num of frames per sub-buffer for sync channels as a power of 2");

static DEFINE_SPINLOCK(dim_lock);

/**
 * struct hdm_channel - private structure to keep channel specific data
 * @name: channel name
 * @is_initialized: identifier to know whether the channel is initialized
 * @ch: HAL specific channel data
 * @reset_dbr_size: reset DBR data buffer size
 * @pending_list: list to keep MBO's before starting transfer
 * @started_list: list to keep MBO's after starting transfer
 * @direction: channel direction (TX or RX)
 * @data_type: channel data type
 */
struct hdm_channel {
	char name[sizeof "caNNN"];
	bool is_initialized;
	struct dim_channel ch;
	u16 *reset_dbr_size;
	struct list_head pending_list;	/* before dim_enqueue_buffer() */
	struct list_head started_list;	/* after dim_enqueue_buffer() */
	enum most_channel_direction direction;
	enum most_channel_data_type data_type;
};

/*
 * struct dim2_hdm - private structure to keep interface specific data
 * @hch: an array of channel specific data
 * @most_iface: most interface structure
 * @capabilities: an array of channel capability data
 * @io_base: I/O register base address
 * @netinfo_task: thread to deliver network status
 * @netinfo_waitq: waitq for the thread to sleep
 * @deliver_netinfo: to identify whether network status received
 * @mac_addrs: INIC mac address
 * @link_state: network link state
 * @atx_idx: index of async tx channel
 */
struct dim2_hdm {
	struct device dev;
	struct hdm_channel hch[DMA_CHANNELS];
	struct most_channel_capability capabilities[DMA_CHANNELS];
	struct most_interface most_iface;
	char name[16 + sizeof "dim2-"];
	void __iomem *io_base;
	u8 clk_speed;
	struct clk *clk;
	struct clk *clk_pll;
	struct task_struct *netinfo_task;
	wait_queue_head_t netinfo_waitq;
	int deliver_netinfo;
	unsigned char mac_addrs[6];
	unsigned char link_state;
	int atx_idx;
	struct medialb_bus bus;
	void (*on_netinfo)(struct most_interface *most_iface,
			   unsigned char link_state, unsigned char *addrs);
	void (*disable_platform)(struct platform_device *pdev);
};

struct dim2_platform_data {
	int (*enable)(struct platform_device *pdev);
	void (*disable)(struct platform_device *pdev);
	u8 fcnt;
};

static inline struct dim2_hdm *iface_to_hdm(struct most_interface *iface)
{
	return container_of(iface, struct dim2_hdm, most_iface);
}

/* Macro to identify a network status message */
#define PACKET_IS_NET_INFO(p)  \
	(((p)[1] == 0x18) && ((p)[2] == 0x05) && ((p)[3] == 0x0C) && \
	 ((p)[13] == 0x3C) && ((p)[14] == 0x00) && ((p)[15] == 0x0A))

static ssize_t state_show(struct device *dev, struct device_attribute *attr,
			  char *buf)
{
	bool state;
	unsigned long flags;

	spin_lock_irqsave(&dim_lock, flags);
	state = dim_get_lock_state();
	spin_unlock_irqrestore(&dim_lock, flags);

	return sysfs_emit(buf, "%s\n", state ? "locked" : "");
}

static DEVICE_ATTR_RO(state);

static struct attribute *dim2_attrs[] = {
	&dev_attr_state.attr,
	NULL,
};

ATTRIBUTE_GROUPS(dim2);

/**
 * dimcb_on_error - callback from HAL to report miscommunication between
 * HDM and HAL
 * @error_id: Error ID
 * @error_message: Error message. Some text in a free format
 */
void dimcb_on_error(u8 error_id, const char *error_message)
{
	pr_err("%s: error_id - %d, error_message - %s\n", __func__, error_id,
	       error_message);
}

/**
 * try_start_dim_transfer - try to transfer a buffer on a channel
 * @hdm_ch: channel specific data
 *
 * Transfer a buffer from pending_list if the channel is ready
 */
static int try_start_dim_transfer(struct hdm_channel *hdm_ch)
{
	u16 buf_size;
	struct list_head *head = &hdm_ch->pending_list;
	struct mbo *mbo;
	unsigned long flags;
	struct dim_ch_state st;

	BUG_ON(!hdm_ch);
	BUG_ON(!hdm_ch->is_initialized);

	spin_lock_irqsave(&dim_lock, flags);
	if (list_empty(head)) {
		spin_unlock_irqrestore(&dim_lock, flags);
		return -EAGAIN;
	}

	if (!dim_get_channel_state(&hdm_ch->ch, &st)->ready) {
		spin_unlock_irqrestore(&dim_lock, flags);
		return -EAGAIN;
	}

	mbo = list_first_entry(head, struct mbo, list);
	buf_size = mbo->buffer_length;

	if (dim_dbr_space(&hdm_ch->ch) < buf_size)