--- /dev/null
+/*
+ * tcm-sita.c
+ *
+ * SImple Tiler Allocator (SiTA): 2D and 1D allocation(reservation) algorithm
+ *
+ * Authors: Ravi Ramachandra <r.ramachandra@ti.com>,
+ * Lajos Molnar <molnar@ti.com>
+ *
+ * Copyright (C) 2009-2010 Texas Instruments, Inc.
+ *
+ * This package 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.
+ *
+ * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ */
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include "tcm-sita.h"
+
+#define ALIGN_DOWN(value, align) ((value) & ~((align) - 1))
+
+/* Individual selection criteria for different scan areas */
+static s32 CR_L2R_T2B = CR_BIAS_HORIZONTAL;
+static s32 CR_R2L_T2B = CR_DIAGONAL_BALANCE;
+
+/*********************************************
+ * TCM API - Sita Implementation
+ *********************************************/
+static s32 sita_reserve_2d(struct tcm *tcm, u16 h, u16 w, u8 align,
+ struct tcm_area *area);
+static s32 sita_reserve_1d(struct tcm *tcm, u32 slots, struct tcm_area *area);
+static s32 sita_free(struct tcm *tcm, struct tcm_area *area);
+static void sita_deinit(struct tcm *tcm);
+
+/*********************************************
+ * Main Scanner functions
+ *********************************************/
+static s32 scan_areas_and_find_fit(struct tcm *tcm, u16 w, u16 h, u16 align,
+ struct tcm_area *area);
+
+static s32 scan_l2r_t2b(struct tcm *tcm, u16 w, u16 h, u16 align,
+ struct tcm_area *field, struct tcm_area *area);
+
+static s32 scan_r2l_t2b(struct tcm *tcm, u16 w, u16 h, u16 align,
+ struct tcm_area *field, struct tcm_area *area);
+
+static s32 scan_r2l_b2t_one_dim(struct tcm *tcm, u32 num_slots,
+ struct tcm_area *field, struct tcm_area *area);
+
+/*********************************************
+ * Support Infrastructure Methods
+ *********************************************/
+static s32 is_area_free(struct tcm_area ***map, u16 x0, u16 y0, u16 w, u16 h);
+
+static s32 update_candidate(struct tcm *tcm, u16 x0, u16 y0, u16 w, u16 h,
+ struct tcm_area *field, s32 criteria,
+ struct score *best);
+
+static void get_nearness_factor(struct tcm_area *field,
+ struct tcm_area *candidate,
+ struct nearness_factor *nf);
+
+static void get_neighbor_stats(struct tcm *tcm, struct tcm_area *area,
+ struct neighbor_stats *stat);
+
+static void fill_area(struct tcm *tcm,
+ struct tcm_area *area, struct tcm_area *parent);
+
+
+/*********************************************/
+
+/*********************************************
+ * Utility Methods
+ *********************************************/
+struct tcm *sita_init(u16 width, u16 height, struct tcm_pt *attr)
+{
+ struct tcm *tcm;
+ struct sita_pvt *pvt;
+ struct tcm_area area = {0};
+ s32 i;
+
+ if (width == 0 || height == 0)
+ return NULL;
+
+ tcm = kmalloc(sizeof(*tcm), GFP_KERNEL);
+ pvt = kmalloc(sizeof(*pvt), GFP_KERNEL);
+ if (!tcm || !pvt)
+ goto error;
+
+ memset(tcm, 0, sizeof(*tcm));
+ memset(pvt, 0, sizeof(*pvt));
+
+ /* Updating the pointers to SiTA implementation APIs */
+ tcm->height = height;
+ tcm->width = width;
+ tcm->reserve_2d = sita_reserve_2d;
+ tcm->reserve_1d = sita_reserve_1d;
+ tcm->free = sita_free;
+ tcm->deinit = sita_deinit;
+ tcm->pvt = (void *)pvt;
+
+ spin_lock_init(&(pvt->lock));
+
+ /* Creating tam map */
+ pvt->map = kmalloc(sizeof(*pvt->map) * tcm->width, GFP_KERNEL);
+ if (!pvt->map)
+ goto error;
+
+ for (i = 0; i < tcm->width; i++) {
+ pvt->map[i] =
+ kmalloc(sizeof(**pvt->map) * tcm->height,
+ GFP_KERNEL);
+ if (pvt->map[i] == NULL) {
+ while (i--)
+ kfree(pvt->map[i]);
+ kfree(pvt->map);
+ goto error;
+ }
+ }
+
+ if (attr && attr->x <= tcm->width && attr->y <= tcm->height) {
+ pvt->div_pt.x = attr->x;
+ pvt->div_pt.y = attr->y;
+
+ } else {
+ /* Defaulting to 3:1 ratio on width for 2D area split */
+ /* Defaulting to 3:1 ratio on height for 2D and 1D split */
+ pvt->div_pt.x = (tcm->width * 3) / 4;
+ pvt->div_pt.y = (tcm->height * 3) / 4;
+ }
+
+ spin_lock(&(pvt->lock));
+ assign(&area, 0, 0, width - 1, height - 1);
+ fill_area(tcm, &area, NULL);
+ spin_unlock(&(pvt->lock));
+ return tcm;
+
+error:
+ kfree(tcm);
+ kfree(pvt);
+ return NULL;
+}
+
+static void sita_deinit(struct tcm *tcm)
+{
+ struct sita_pvt *pvt = (struct sita_pvt *)tcm->pvt;
+ struct tcm_area area = {0};
+ s32 i;
+
+ area.p1.x = tcm->width - 1;
+ area.p1.y = tcm->height - 1;
+
+ spin_lock(&(pvt->lock));
+ fill_area(tcm, &area, NULL);
+ spin_unlock(&(pvt->lock));
+
+ for (i = 0; i < tcm->height; i++)
+ kfree(pvt->map[i]);
+ kfree(pvt->map);
+ kfree(pvt);
+}
+
+/**
+ * Reserve a 1D area in the container
+ *
+ * @param num_slots size of 1D area
+ * @param area pointer to the area that will be populated with the
+ * reserved area
+ *
+ * @return 0 on success, non-0 error value on failure.
+ */
+static s32 sita_reserve_1d(struct tcm *tcm, u32 num_slots,
+ struct tcm_area *area)
+{
+ s32 ret;
+ struct tcm_area field = {0};
+ struct sita_pvt *pvt = (struct sita_pvt *)tcm->pvt;
+
+ spin_lock(&(pvt->lock));
+
+ /* Scanning entire container */
+ assign(&field, tcm->width - 1, tcm->height - 1, 0, 0);
+
+ ret = scan_r2l_b2t_one_dim(tcm, num_slots, &field, area);
+ if (!ret)
+ /* update map */
+ fill_area(tcm, area, area);
+
+ spin_unlock(&(pvt->lock));
+ return ret;
+}
+
+/**
+ * Reserve a 2D area in the container
+ *
+ * @param w width
+ * @param h height
+ * @param area pointer to the area that will be populated with the reserved
+ * area
+ *
+ * @return 0 on success, non-0 error value on failure.
+ */
+static s32 sita_reserve_2d(struct tcm *tcm, u16 h, u16 w, u8 align,
+ struct tcm_area *area)
+{
+ s32 ret;
+ struct sita_pvt *pvt = (struct sita_pvt *)tcm->pvt;
+
+ /* not supporting more than 64 as alignment */
+ if (align > 64)
+ return -EINVAL;
+
+ /* we prefer 1, 32 and 64 as alignment */
+ align = align <= 1 ? 1 : align <= 32 ? 32 : 64;
+
+ spin_lock(&(pvt->lock));
+ ret = scan_areas_and_find_fit(tcm, w, h, align, area);
+ if (!ret)
+ /* update map */
+ fill_area(tcm, area, area);
+
+ spin_unlock(&(pvt->lock));
+ return ret;
+}
+
+/**
+ * Unreserve a previously allocated 2D or 1D area
+ * @param area area to be freed
+ * @return 0 - success
+ */
+static s32 sita_free(struct tcm *tcm, struct tcm_area *area)
+{
+ struct sita_pvt *pvt = (struct sita_pvt *)tcm->pvt;
+
+ spin_lock(&(pvt->lock));
+
+ /* check that this is in fact an existing area */
+ WARN_ON(pvt->map[area->p0.x][area->p0.y] != area ||
+ pvt->map[area->p1.x][area->p1.y] != area);
+
+ /* Clear the contents of the associated tiles in the map */
+ fill_area(tcm, area, NULL);
+
+ spin_unlock(&(pvt->lock));
+
+ return 0;
+}
+
+/**
+ * Note: In general the cordinates in the scan field area relevant to the can
+ * sweep directions. The scan origin (e.g. top-left corner) will always be
+ * the p0 member of the field. Therfore, for a scan from top-left p0.x <= p1.x
+ * and p0.y <= p1.y; whereas, for a scan from bottom-right p1.x <= p0.x and p1.y
+ * <= p0.y
+ */
+
+/**
+ * Raster scan horizontally right to left from top to bottom to find a place for
+ * a 2D area of given size inside a scan field.
+ *
+ * @param w width of desired area
+ * @param h height of desired area
+ * @param align desired area alignment
+ * @param area pointer to the area that will be set to the best position
+ * @param field area to scan (inclusive)
+ *
+ * @return 0 on success, non-0 error value on failure.
+ */
+static s32 scan_r2l_t2b(struct tcm *tcm, u16 w, u16 h, u16 align,
+ struct tcm_area *field, struct tcm_area *area)
+{
+ s32 x, y;
+ s16 start_x, end_x, start_y, end_y, found_x = -1;
+ struct tcm_area ***map = ((struct sita_pvt *)tcm->pvt)->map;
+ struct score best = {{0}, {0}, {0}, 0};
+
+ start_x = field->p0.x;
+ end_x = field->p1.x;
+ start_y = field->p0.y;
+ end_y = field->p1.y;
+
+ /* check scan area co-ordinates */
+ if (field->p0.x < field->p1.x ||
+ field->p1.y < field->p0.y)
+ return -EINVAL;
+
+ /* check if allocation would fit in scan area */
+ if (w > LEN(start_x, end_x) || h > LEN(end_y, start_y))
+ return -ENOSPC;
+
+ /* adjust start_x and end_y, as allocation would not fit beyond */
+ start_x = ALIGN_DOWN(start_x - w + 1, align); /* - 1 to be inclusive */
+ end_y = end_y - h + 1;
+
+ /* check if allocation would still fit in scan area */
+ if (start_x < end_x)
+ return -ENOSPC;
+
+ /* scan field top-to-bottom, right-to-left */
+ for (y = start_y; y <= end_y; y++) {
+ for (x = start_x; x >= end_x; x -= align) {
+ if (is_area_free(map, x, y, w, h)) {
+ found_x = x;
+
+ /* update best candidate */
+ if (update_candidate(tcm, x, y, w, h, field,
+ CR_R2L_T2B, &best))
+ goto done;
+
+ /* change upper x bound */
+ end_x = x + 1;
+ break;
+ } else if (map[x][y] && map[x][y]->is2d) {
+ /* step over 2D areas */
+ x = ALIGN(map[x][y]->p0.x - w + 1, align);
+ }
+ }
+
+ /* break if you find a free area shouldering the scan field */
+ if (found_x == start_x)
+ break;
+ }
+
+ if (!best.a.tcm)
+ return -ENOSPC;
+done:
+ assign(area, best.a.p0.x, best.a.p0.y, best.a.p1.x, best.a.p1.y);
+ return 0;
+}
+
+/**
+ * Raster scan horizontally left to right from top to bottom to find a place for
+ * a 2D area of given size inside a scan field.
+ *
+ * @param w width of desired area
+ * @param h height of desired area
+ * @param align desired area alignment
+ * @param area pointer to the area that will be set to the best position
+ * @param field area to scan (inclusive)
+ *
+ * @return 0 on success, non-0 error value on failure.
+ */
+static s32 scan_l2r_t2b(struct tcm *tcm, u16 w, u16 h, u16 align,
+ struct tcm_area *field, struct tcm_area *area)
+{
+ s32 x, y;
+ s16 start_x, end_x, start_y, end_y, found_x = -1;
+ struct tcm_area ***map = ((struct sita_pvt *)tcm->pvt)->map;
+ struct score best = {{0}, {0}, {0}, 0};
+
+ start_x = field->p0.x;
+ end_x = field->p1.x;
+ start_y = field->p0.y;
+ end_y = field->p1.y;
+
+ /* check scan area co-ordinates */
+ if (field->p1.x < field->p0.x ||
+ field->p1.y < field->p0.y)
+ return -EINVAL;
+
+ /* check if allocation would fit in scan area */
+ if (w > LEN(end_x, start_x) || h > LEN(end_y, start_y))
+ return -ENOSPC;
+
+ start_x = ALIGN(start_x, align);
+
+ /* check if allocation would still fit in scan area */
+ if (w > LEN(end_x, start_x))
+ return -ENOSPC;
+
+ /* adjust end_x and end_y, as allocation would not fit beyond */
+ end_x = end_x - w + 1; /* + 1 to be inclusive */
+ end_y = end_y - h + 1;
+
+ /* scan field top-to-bottom, left-to-right */
+ for (y = start_y; y <= end_y; y++) {
+ for (x = start_x; x <= end_x; x += align) {
+ if (is_area_free(map, x, y, w, h)) {
+ found_x = x;
+
+ /* update best candidate */
+ if (update_candidate(tcm, x, y, w, h, field,
+ CR_L2R_T2B, &best))
+ goto done;
+ /* change upper x bound */
+ end_x = x - 1;
+
+ break;
+ } else if (map[x][y] && map[x][y]->is2d) {
+ /* step over 2D areas */
+ x = ALIGN_DOWN(map[x][y]->p1.x, align);
+ }
+ }
+
+ /* break if you find a free area shouldering the scan field */
+ if (found_x == start_x)
+ break;
+ }
+
+ if (!best.a.tcm)
+ return -ENOSPC;
+done:
+ assign(area, best.a.p0.x, best.a.p0.y, best.a.p1.x, best.a.p1.y);
+ return 0;
+}
+
+/**
+ * Raster scan horizontally right to left from bottom to top to find a place
+ * for a 1D area of given size inside a scan field.
+ *
+ * @param num_slots size of desired area
+ * @param align desired area alignment
+ * @param area pointer to the area that will be set to the best
+ * position
+ * @param field area to scan (inclusive)
+ *
+ * @return 0 on success, non-0 error value on failure.
+ */
+static s32 scan_r2l_b2t_one_dim(struct tcm *tcm, u32 num_slots,
+ struct tcm_area *field, struct tcm_area *area)
+{
+ s32 found = 0;
+ s16 x, y;
+ struct sita_pvt *pvt = (struct sita_pvt *)tcm->pvt;
+ struct tcm_area *p;
+
+ /* check scan area co-ordinates */
+ if (field->p0.y < field->p1.y)
+ return -EINVAL;
+
+ /**
+ * Currently we only support full width 1D scan field, which makes sense
+ * since 1D slot-ordering spans the full container width.
+ */
+ if (tcm->width != field->p0.x - field->p1.x + 1)
+ return -EINVAL;
+
+ /* check if allocation would fit in scan area */
+ if (num_slots > tcm->width * LEN(field->p0.y, field->p1.y))
+ return -ENOSPC;
+
+ x = field->p0.x;
+ y = field->p0.y;
+
+ /* find num_slots consecutive free slots to the left */
+ while (found < num_slots) {
+ if (y < 0)
+ return -ENOSPC;
+
+ /* remember bottom-right corner */
+ if (found == 0) {
+ area->p1.x = x;
+ area->p1.y = y;
+ }
+
+ /* skip busy regions */
+ p = pvt->map[x][y];
+ if (p) {
+ /* move to left of 2D areas, top left of 1D */
+ x = p->p0.x;
+ if (!p->is2d)
+ y = p->p0.y;
+
+ /* start over */
+ found = 0;
+ } else {
+ /* count consecutive free slots */
+ found++;
+ if (found == num_slots)
+ break;
+ }
+
+ /* move to the left */
+ if (x == 0)
+ y--;
+ x = (x ? : tcm->width) - 1;
+
+ }
+
+ /* set top-left corner */
+ area->p0.x = x;
+ area->p0.y = y;
+ return 0;
+}
+
+/**
+ * Find a place for a 2D area of given size inside a scan field based on its
+ * alignment needs.
+ *
+ * @param w width of desired area
+ * @param h height of desired area
+ * @param align desired area alignment
+ * @param area pointer to the area that will be set to the best position
+ *
+ * @return 0 on success, non-0 error value on failure.
+ */
+static s32 scan_areas_and_find_fit(struct tcm *tcm, u16 w, u16 h, u16 align,
+ struct tcm_area *area)
+{
+ s32 ret = 0;
+ struct tcm_area field = {0};
+ u16 boundary_x, boundary_y;
+ struct sita_pvt *pvt = (struct sita_pvt *)tcm->pvt;
+
+ if (align > 1) {
+ /* prefer top-left corner */
+ boundary_x = pvt->div_pt.x - 1;
+ boundary_y = pvt->div_pt.y - 1;
+
+ /* expand width and height if needed */
+ if (w > pvt->div_pt.x)
+ boundary_x = tcm->width - 1;
+ if (h > pvt->div_pt.y)
+ boundary_y = tcm->height - 1;
+
+ assign(&field, 0, 0, boundary_x, boundary_y);
+ ret = scan_l2r_t2b(tcm, w, h, align, &field, area);
+
+ /* scan whole container if failed, but do not scan 2x */
+ if (ret != 0 && (boundary_x != tcm->width - 1 ||
+ boundary_y != tcm->height - 1)) {
+ /* scan the entire container if nothing found */
+ assign(&field, 0, 0, tcm->width - 1, tcm->height - 1);
+ ret = scan_l2r_t2b(tcm, w, h, align, &field, area);
+ }
+ } else if (align == 1) {
+ /* prefer top-right corner */
+ boundary_x = pvt->div_pt.x;
+ boundary_y = pvt->div_pt.y - 1;
+
+ /* expand width and height if needed */
+ if (w > (tcm->width - pvt->div_pt.x))
+ boundary_x = 0;
+ if (h > pvt->div_pt.y)
+ boundary_y = tcm->height - 1;
+
+ assign(&field, tcm->width - 1, 0, boundary_x, boundary_y);
+ ret = scan_r2l_t2b(tcm, w, h, align, &field, area);
+
+ /* scan whole container if failed, but do not scan 2x */
+ if (ret != 0 && (boundary_x != 0 ||
+ boundary_y != tcm->height - 1)) {
+ /* scan the entire container if nothing found */
+ assign(&field, tcm->width - 1, 0, 0, tcm->height - 1);
+ ret = scan_r2l_t2b(tcm, w, h, align, &field,
+ area);
+ }
+ }
+
+ return ret;
+}
+
+/* check if an entire area is free */
+static s32 is_area_free(struct tcm_area ***map, u16 x0, u16 y0, u16 w, u16 h)
+{
+ u16 x = 0, y = 0;
+ for (y = y0; y < y0 + h; y++) {
+ for (x = x0; x < x0 + w; x++) {
+ if (map[x][y])
+ return false;
+ }
+ }
+ return true;
+}
+
+/* fills an area with a parent tcm_area */
+static void fill_area(struct tcm *tcm, struct tcm_area *area,
+ struct tcm_area *parent)
+{
+ s32 x, y;
+ struct sita_pvt *pvt = (struct sita_pvt *)tcm->pvt;
+ struct tcm_area a, a_;
+
+ /* set area's tcm; otherwise, enumerator considers it invalid */
+ area->tcm = tcm;
+
+ tcm_for_each_slice(a, *area, a_) {
+ for (x = a.p0.x; x <= a.p1.x; ++x)
+ for (y = a.p0.y; y <= a.p1.y; ++y)
+ pvt->map[x][y] = parent;
+
+ }
+}
+
+/**
+ * Compares a candidate area to the current best area, and if it is a better
+ * fit, it updates the best to this one.
+ *
+ * @param x0, y0, w, h top, left, width, height of candidate area
+ * @param field scan field
+ * @param criteria scan criteria
+ * @param best best candidate and its scores
+ *
+ * @return 1 (true) if the candidate area is known to be the final best, so no
+ * more searching should be performed
+ */
+static s32 update_candidate(struct tcm *tcm, u16 x0, u16 y0, u16 w, u16 h,
+ struct tcm_area *field, s32 criteria,
+ struct score *best)
+{
+ struct score me; /* score for area */
+
+ /*
+ * NOTE: For horizontal bias we always give the first found, because our
+ * scan is horizontal-raster-based and the first candidate will always
+ * have the horizontal bias.
+ */
+ bool first = criteria & CR_BIAS_HORIZONTAL;
+
+ assign(&me.a, x0, y0, x0 + w - 1, y0 + h - 1);
+
+ /* calculate score for current candidate */
+ if (!first) {
+ get_neighbor_stats(tcm, &me.a, &me.n);
+ me.neighs = me.n.edge + me.n.busy;
+ get_nearness_factor(field, &me.a, &me.f);
+ }
+
+ /* the 1st candidate is always the best */
+ if (!best->a.tcm)
+ goto better;
+
+ BUG_ON(first);
+
+ /* diagonal balance check */
+ if ((criteria & CR_DIAGONAL_BALANCE) &&
+ best->neighs <= me.neighs &&
+ (best->neighs < me.neighs ||
+ /* this implies that neighs and occupied match */
+ best->n.busy < me.n.busy ||
+ (best->n.busy == me.n.busy &&
+ /* check the nearness factor */
+ best->f.x + best->f.y > me.f.x + me.f.y)))
+ goto better;
+
+ /* not better, keep going */
+ return 0;
+
+better:
+ /* save current area as best */
+ memcpy(best, &me, sizeof(me));
+ best->a.tcm = tcm;
+ return first;
+}
+
+/**
+ * Calculate the nearness factor of an area in a search field. The nearness
+ * factor is smaller if the area is closer to the search origin.
+ */
+static void get_nearness_factor(struct tcm_area *field, struct tcm_area *area,
+ struct nearness_factor *nf)
+{
+ /**
+ * Using signed math as field coordinates may be reversed if
+ * search direction is right-to-left or bottom-to-top.
+ */
+ nf->x = (s32)(area->p0.x - field->p0.x) * 1000 /
+ (field->p1.x - field->p0.x);
+ nf->y = (s32)(area->p0.y - field->p0.y) * 1000 /
+ (field->p1.y - field->p0.y);
+}
+
+/* get neighbor statistics */
+static void get_neighbor_stats(struct tcm *tcm, struct tcm_area *area,
+ struct neighbor_stats *stat)
+{
+ s16 x = 0, y = 0;
+ struct sita_pvt *pvt = (struct sita_pvt *)tcm->pvt;
+
+ /* Clearing any exisiting values */
+ memset(stat, 0, sizeof(*stat));
+
+ /* process top & bottom edges */
+ for (x = area->p0.x; x <= area->p1.x; x++) {
+ if (area->p0.y == 0)
+ stat->edge++;
+ else if (pvt->map[x][area->p0.y - 1])
+ stat->busy++;
+
+ if (area->p1.y == tcm->height - 1)
+ stat->edge++;
+ else if (pvt->map[x][area->p1.y + 1])
+ stat->busy++;
+ }
+
+ /* process left & right edges */
+ for (y = area->p0.y; y <= area->p1.y; ++y) {
+ if (area->p0.x == 0)
+ stat->edge++;
+ else if (pvt->map[area->p0.x - 1][y])
+ stat->busy++;
+
+ if (area->p1.x == tcm->width - 1)
+ stat->edge++;
+ else if (pvt->map[area->p1.x + 1][y])
+ stat->busy++;
+ }
+}
Code Review / kvmfornfv.git / blobdiff