#include <linux/seq_file.h> // For seq_* functions and types
#include <linux/version.h>  // Macros to detect kernel version

#include "nvdebug.h"

#define RUNLIST_PROCFS_NAME "runlist"
#define DETAILED_CHANNEL_INFO

static int runlist_detail_seq_show_chan(struct seq_file *s, struct gk20a *g, uint32_t chid) {
	channel_ctrl_t chan;
	char *loc_txt;
	u64 instance_ptr;
	chan.raw = nvdebug_readq(g, NV_PCCSR_CHANNEL_INST(chid));
	loc_txt = target_to_text(chan.inst_target);
	if (!loc_txt)
		return -EIO;
	instance_ptr = chan.inst_ptr;
	instance_ptr <<= 12;
	seq_printf(s, "  +- Channel Info %-4d -+\n", chid);
	seq_printf(s, "  | Enabled:           %d|\n", chan.enable);
	seq_printf(s, "  | Next:              %d|\n", chan.next);
	seq_printf(s, "  | Force CTX Reload:  %d|\n", chan.force_ctx_reload);
	seq_printf(s, "  | Enable set:        %d|\n", chan.enable_set);
	seq_printf(s, "  | Enable clear:      %d|\n", chan.enable_clear);
	seq_printf(s, "  | PBDMA Faulted:     %d|\n", chan.pbdma_faulted);
	seq_printf(s, "  | ENG Faulted:       %d|\n", chan.eng_faulted);
	seq_printf(s, "  | Status:           %2d|\n", chan.status);
	seq_printf(s, "  | Busy:              %d|\n", chan.busy);
	seq_printf(s, "  | Instance PTR:       |\n");
	seq_printf(s, "  | %#018llx  |\n", instance_ptr);
	seq_printf(s, "  | %-20s|\n", loc_txt);
	seq_printf(s, "  | Instance bound:    %d|\n", chan.inst_bind);
	seq_printf(s, "  +---------------------+\n");
	return 0;
}

#if LINUX_VERSION_CODE < KERNEL_VERSION(4,19,0)
// Bug workaround. See comment in runlist_file_seq_start()
static loff_t pos_fixup;
#endif

static void *runlist_file_seq_start(struct seq_file *s, loff_t *pos) {
	static struct runlist_iter rl_iter;
	// *pos == 0 for first call after read of file
	if (*pos == 0) {
		int err = get_runlist_iter(&rl_iter);
		if (err)
			return NULL;
		return &rl_iter;
	}
	// If we're resuming an earlier print
	if (*pos < rl_iter.rl_info.len) {
#if LINUX_VERSION_CODE < KERNEL_VERSION(4,19,0)
		// There's a nasty bug prior to 4.19-rc1 that if the buffer overflows, the
		// last update to `pos` is not saved. Work around that here by reloading a
		// saved copy of `pos`.
		if (!pos_fixup)
			return NULL;
		*pos = pos_fixup;
#endif
		return &rl_iter;
	}
	// When called with *pos != 0, we already traversed the runlist
	return NULL;
}

static void* runlist_file_seq_next(struct seq_file *s, void *raw_rl_iter,
				   loff_t *pos) {
	struct runlist_iter* rl_iter = raw_rl_iter;
	void *ret = NULL;
	// Advance by one TSG + channels under last TSG
	*pos += 1 + rl_iter->curr_tsg->tsg_length;
	// Verify we haven't reached the end of the runlist
	// rl_info.len is the num of tsg entries + total num of channel entries
	if (*pos < rl_iter->rl_info.len) {
		rl_iter->curr_tsg = next_tsg(rl_iter->curr_tsg);
		ret = rl_iter;
	}
#if LINUX_VERSION_CODE < KERNEL_VERSION(4,19,0)
	// Bug workaround. See comment in runlist_file_seq_start()
	pos_fixup = ret ? *pos : 0;
#endif
	return ret;
}

static void runlist_file_seq_stop(struct seq_file *s, void *raw_rl_iter) {
	// No cleanup needed
}

static int runlist_file_seq_show(struct seq_file *s, void *raw_rl_iter) {
	struct entry_tsg* tsg = ((struct runlist_iter*)raw_rl_iter)->curr_tsg;
	struct runlist_chan* chan;
	struct gk20a *g = get_live_gk20a();
	if (!g)
		return -EIO;
	if (tsg->entry_type != ENTRY_TYPE_TSG) {
                printk(KERN_WARNING "[nvdebug] Attempted to print non-TSG in tsg print logic!\n");
                return -EIO;
        }
        seq_printf(s, "+---- TSG Entry %-2d----+\n", tsg->tsgid);
        seq_printf(s, "| Scale: %-13d|\n", tsg->timeslice_scale);
        seq_printf(s, "| Timeout: %-11d|\n", tsg->timeslice_timeout);
        seq_printf(s, "+---------------------+\n");
	for_chan_in_tsg(chan, tsg) {
#ifndef DETAILED_CHANNEL_INFO
		char* loc_txt;
		u64 instance_ptr;
#endif
		if (chan->entry_type != ENTRY_TYPE_CHAN) {
			printk(KERN_WARNING "[nvdebug] Attempted to print non-channel in channel print logic!\n");
			return -EIO;
		}
#ifdef DETAILED_CHANNEL_INFO
		runlist_detail_seq_show_chan(s, g, chan->chid);
#else
		loc_txt = target_to_text(chan->inst_target);
		if (!loc_txt) {
			printk(KERN_WARNING "[nvdebug] Invalid apature in channel print logic!\n");
			return -EIO;
		}
		// Reconstruct pointer to channel instance block
		instance_ptr = chan->inst_ptr_hi;
		instance_ptr <<= 32;
		instance_ptr |= chan->inst_ptr_lo << 12;

		seq_printf(s, "  +- Channel Entry %-4d-+\n", chan->chid);
		seq_printf(s, "  | Runqueue Selector: %d|\n", chan->runqueue_selector);
		seq_printf(s, "  | Instance PTR:       |\n");
		seq_printf(s, "  | %#018llx  |\n", instance_ptr);
		seq_printf(s, "  | %-20s|\n", loc_txt);
		seq_printf(s, "  +---------------------+\n");
#endif
	}
	return 0;
}

static const struct seq_operations runlist_file_seq_ops = {
        .start = runlist_file_seq_start,
        .next = runlist_file_seq_next,
        .stop = runlist_file_seq_stop,
        .show = runlist_file_seq_show,
};

static int runlist_file_open(struct inode *inode, struct file *f) {
	return seq_open(f, &runlist_file_seq_ops);
}

const struct file_operations runlist_file_ops = {
	.open = runlist_file_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = seq_release,
};