drm/omap: Use bitmaps for TILER placement
Modified Tiler placement to utilize bitmaps for bookkeeping and
all placement algorithms. This resulted in a substantial savings
in time for all Tiler reservation and free operations. Typical
savings are in the range of 28% decrease in time taken with larger
buffers showing a 80%+ decrease.
Signed-off-by: Andy Gross <andy.gross@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/gpu/drm/omapdrm/tcm-sita.c b/drivers/gpu/drm/omapdrm/tcm-sita.c
index 6df1f2a..c10fdfc 100644
--- a/drivers/gpu/drm/omapdrm/tcm-sita.c
+++ b/drivers/gpu/drm/omapdrm/tcm-sita.c
@@ -5,8 +5,9 @@
*
* Authors: Ravi Ramachandra <r.ramachandra@ti.com>,
* Lajos Molnar <molnar@ti.com>
+ * Andy Gross <andy.gross@ti.com>
*
- * Copyright (C) 2009-2010 Texas Instruments, Inc.
+ * Copyright (C) 2012 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
@@ -17,79 +18,225 @@
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
*/
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/bitmap.h>
#include <linux/slab.h>
-#include <linux/spinlock.h>
+#include "tcm.h"
-#include "tcm-sita.h"
+static unsigned long mask[8];
+/*
+ * pos position in bitmap
+ * w width in slots
+ * h height in slots
+ * map ptr to bitmap
+ * stride slots in a row
+ */
+static void free_slots(unsigned long pos, uint16_t w, uint16_t h,
+ unsigned long *map, uint16_t stride)
+{
+ int i;
-#define ALIGN_DOWN(value, align) ((value) & ~((align) - 1))
+ for (i = 0; i < h; i++, pos += stride)
+ bitmap_clear(map, pos, w);
+}
-/* Individual selection criteria for different scan areas */
-static s32 CR_L2R_T2B = CR_BIAS_HORIZONTAL;
-static s32 CR_R2L_T2B = CR_DIAGONAL_BALANCE;
+/*
+ * w width in slots
+ * pos ptr to position
+ * map ptr to bitmap
+ * num_bits number of bits in bitmap
+ */
+static int r2l_b2t_1d(uint16_t w, unsigned long *pos, unsigned long *map,
+ size_t num_bits)
+{
+ unsigned long search_count = 0;
+ unsigned long bit;
+ bool area_found = false;
-/*********************************************
- * 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);
+ *pos = num_bits - w;
-/*********************************************
- * Main Scanner functions
- *********************************************/
-static s32 scan_areas_and_find_fit(struct tcm *tcm, u16 w, u16 h, u16 align,
- struct tcm_area *area);
+ while (search_count < num_bits) {
+ bit = find_next_bit(map, num_bits, *pos);
-static s32 scan_l2r_t2b(struct tcm *tcm, u16 w, u16 h, u16 align,
- struct tcm_area *field, struct tcm_area *area);
+ if (bit - *pos >= w) {
+ /* found a long enough free area */
+ bitmap_set(map, *pos, w);
+ area_found = true;
+ break;
+ }
-static s32 scan_r2l_t2b(struct tcm *tcm, u16 w, u16 h, u16 align,
- struct tcm_area *field, struct tcm_area *area);
+ search_count = num_bits - bit + w;
+ *pos = bit - w;
+ }
-static s32 scan_r2l_b2t_one_dim(struct tcm *tcm, u32 num_slots,
- struct tcm_area *field, struct tcm_area *area);
+ return (area_found) ? 0 : -ENOMEM;
+}
-/*********************************************
- * Support Infrastructure Methods
- *********************************************/
-static s32 is_area_free(struct tcm_area ***map, u16 x0, u16 y0, u16 w, u16 h);
+/*
+ * w = width in slots
+ * h = height in slots
+ * a = align in slots (mask, 2^n-1, 0 is unaligned)
+ * offset = offset in bytes from 4KiB
+ * pos = position in bitmap for buffer
+ * map = bitmap ptr
+ * num_bits = size of bitmap
+ * stride = bits in one row of container
+ */
+static int l2r_t2b(uint16_t w, uint16_t h, uint16_t a, int16_t offset,
+ unsigned long *pos, unsigned long slot_bytes,
+ unsigned long *map, size_t num_bits, size_t slot_stride)
+{
+ int i;
+ unsigned long index;
+ bool area_free;
+ unsigned long slots_per_band = PAGE_SIZE / slot_bytes;
+ unsigned long bit_offset = (offset > 0) ? offset / slot_bytes : 0;
+ unsigned long curr_bit = bit_offset;
-static s32 update_candidate(struct tcm *tcm, u16 x0, u16 y0, u16 w, u16 h,
- struct tcm_area *field, s32 criteria,
- struct score *best);
+ /* reset alignment to 1 if we are matching a specific offset */
+ /* adjust alignment - 1 to get to the format expected in bitmaps */
+ a = (offset > 0) ? 0 : a - 1;
-static void get_nearness_factor(struct tcm_area *field,
- struct tcm_area *candidate,
- struct nearness_factor *nf);
+ /* FIXME Return error if slots_per_band > stride */
-static void get_neighbor_stats(struct tcm *tcm, struct tcm_area *area,
- struct neighbor_stats *stat);
+ while (curr_bit < num_bits) {
+ *pos = bitmap_find_next_zero_area(map, num_bits, curr_bit, w,
+ a);
-static void fill_area(struct tcm *tcm,
- struct tcm_area *area, struct tcm_area *parent);
+ /* skip forward if we are not at right offset */
+ if (bit_offset > 0 && (*pos % slots_per_band != bit_offset)) {
+ curr_bit = ALIGN(*pos, slots_per_band) + bit_offset;
+ continue;
+ }
+ /* skip forward to next row if we overlap end of row */
+ if ((*pos % slot_stride) + w > slot_stride) {
+ curr_bit = ALIGN(*pos, slot_stride) + bit_offset;
+ continue;
+ }
-/*********************************************/
+ /* TODO: Handle overlapping 4K boundaries */
-/*********************************************
- * Utility Methods
- *********************************************/
-struct tcm *sita_init(u16 width, u16 height, struct tcm_pt *attr)
+ /* break out of look if we will go past end of container */
+ if ((*pos + slot_stride * h) > num_bits)
+ break;
+
+ /* generate mask that represents out matching pattern */
+ bitmap_clear(mask, 0, slot_stride);
+ bitmap_set(mask, (*pos % BITS_PER_LONG), w);
+
+ /* assume the area is free until we find an overlap */
+ area_free = true;
+
+ /* check subsequent rows to see if complete area is free */
+ for (i = 1; i < h; i++) {
+ index = *pos / BITS_PER_LONG + i * 8;
+ if (bitmap_intersects(&map[index], mask,
+ (*pos % BITS_PER_LONG) + w)) {
+ area_free = false;
+ break;
+ }
+ }
+
+ if (area_free)
+ break;
+
+ /* go forward past this match */
+ if (bit_offset > 0)
+ curr_bit = ALIGN(*pos, slots_per_band) + bit_offset;
+ else
+ curr_bit = *pos + a + 1;
+ }
+
+ if (area_free) {
+ /* set area as in-use. iterate over rows */
+ for (i = 0, index = *pos; i < h; i++, index += slot_stride)
+ bitmap_set(map, index, w);
+ }
+
+ return (area_free) ? 0 : -ENOMEM;
+}
+
+static s32 sita_reserve_1d(struct tcm *tcm, u32 num_slots,
+ struct tcm_area *area)
+{
+ unsigned long pos;
+ int ret;
+
+ spin_lock(&(tcm->lock));
+ ret = r2l_b2t_1d(num_slots, &pos, tcm->bitmap, tcm->map_size);
+ if (!ret) {
+ area->p0.x = pos % tcm->width;
+ area->p0.y = pos / tcm->width;
+ area->p1.x = (pos + num_slots - 1) % tcm->width;
+ area->p1.y = (pos + num_slots - 1) / tcm->width;
+ }
+ spin_unlock(&(tcm->lock));
+
+ return ret;
+}
+
+static s32 sita_reserve_2d(struct tcm *tcm, u16 h, u16 w, u16 align,
+ int16_t offset, uint16_t slot_bytes,
+ struct tcm_area *area)
+{
+ unsigned long pos;
+ int ret;
+
+ spin_lock(&(tcm->lock));
+ ret = l2r_t2b(w, h, align, offset, &pos, slot_bytes, tcm->bitmap,
+ tcm->map_size, tcm->width);
+
+ if (!ret) {
+ area->p0.x = pos % tcm->width;
+ area->p0.y = pos / tcm->width;
+ area->p1.x = area->p0.x + w - 1;
+ area->p1.y = area->p0.y + h - 1;
+ }
+ spin_unlock(&(tcm->lock));
+
+ return ret;
+}
+
+static void sita_deinit(struct tcm *tcm)
+{
+ kfree(tcm);
+}
+
+static s32 sita_free(struct tcm *tcm, struct tcm_area *area)
+{
+ unsigned long pos;
+ uint16_t w, h;
+
+ pos = area->p0.x + area->p0.y * tcm->width;
+ if (area->is2d) {
+ w = area->p1.x - area->p0.x + 1;
+ h = area->p1.y - area->p0.y + 1;
+ } else {
+ w = area->p1.x + area->p1.y * tcm->width - pos + 1;
+ h = 1;
+ }
+
+ spin_lock(&(tcm->lock));
+ free_slots(pos, w, h, tcm->bitmap, tcm->width);
+ spin_unlock(&(tcm->lock));
+ return 0;
+}
+
+struct tcm *sita_init(u16 width, u16 height)
{
struct tcm *tcm;
- struct sita_pvt *pvt;
- struct tcm_area area = {0};
- s32 i;
+ size_t map_size = BITS_TO_LONGS(width*height) * sizeof(unsigned long);
if (width == 0 || height == 0)
return NULL;
- tcm = kzalloc(sizeof(*tcm), GFP_KERNEL);
- pvt = kzalloc(sizeof(*pvt), GFP_KERNEL);
- if (!tcm || !pvt)
+ tcm = kzalloc(sizeof(*tcm) + map_size, GFP_KERNEL);
+ if (!tcm)
goto error;
/* Updating the pointers to SiTA implementation APIs */
@@ -99,602 +246,16 @@
tcm->reserve_1d = sita_reserve_1d;
tcm->free = sita_free;
tcm->deinit = sita_deinit;
- tcm->pvt = (void *)pvt;
- spin_lock_init(&(pvt->lock));
+ spin_lock_init(&tcm->lock);
+ tcm->bitmap = (unsigned long *)(tcm + 1);
+ bitmap_clear(tcm->bitmap, 0, width*height);
- /* Creating tam map */
- pvt->map = kmalloc(sizeof(*pvt->map) * tcm->width, GFP_KERNEL);
- if (!pvt->map)
- goto error;
+ tcm->map_size = width*height;
- 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++;
- }
-}