OMAP: Add support for VRFB rotation engine

VRFB rotation engine is a block in OMAP2/3 that offers 12 independent
contexts that can be used for framebuffer rotation.

Each context has a backend area of real memory, where it stores the
pixels in undisclosed format. This memory is offered to users via 4
virtual memory areas, which see the same memory area in different
rotation angles (0, 90, 180 and 270 degrees).

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>

3 files changed, 319 insertions, 0 deletions

diff --git a/drivers/video/omap2/Kconfig b/drivers/video/omap2/Kconfig
index 7a6c4c9..ac8b650 100644
--- a/drivers/video/omap2/Kconfig
+++ b/drivers/video/omap2/Kconfig
@@ -1,2 +1,5 @@
 config OMAP2_VRAM
 	bool
+
+config OMAP2_VRFB
+	bool
diff --git a/drivers/video/omap2/Makefile b/drivers/video/omap2/Makefile
index 7fdf7bd..aa3751b 100644
--- a/drivers/video/omap2/Makefile
+++ b/drivers/video/omap2/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_OMAP2_VRAM) += vram.o
+obj-$(CONFIG_OMAP2_VRFB) += vrfb.o
diff --git a/drivers/video/omap2/vrfb.c b/drivers/video/omap2/vrfb.c
new file mode 100644
index 0000000..fd22716
--- /dev/null
+++ b/drivers/video/omap2/vrfb.c
@@ -0,0 +1,315 @@
+/*
+ * VRFB Rotation Engine
+ *
+ * Copyright (C) 2009 Nokia Corporation
+ * Author: Tomi Valkeinen <tomi.valkeinen@nokia.com>
+ *
+ * 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.
+ *
+ * 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+/*#define DEBUG*/
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/bitops.h>
+#include <linux/mutex.h>
+
+#include <mach/io.h>
+#include <plat/vrfb.h>
+#include <plat/sdrc.h>
+
+#ifdef DEBUG
+#define DBG(format, ...) pr_debug("VRFB: " format, ## __VA_ARGS__)
+#else
+#define DBG(format, ...)
+#endif
+
+#define SMS_ROT_VIRT_BASE(context, rot) \
+	(((context >= 4) ? 0xD0000000 : 0x70000000) \
+	 + (0x4000000 * (context)) \
+	 + (0x1000000 * (rot)))
+
+#define OMAP_VRFB_SIZE			(2048 * 2048 * 4)
+
+#define VRFB_PAGE_WIDTH_EXP	5 /* Assuming SDRAM pagesize= 1024 */
+#define VRFB_PAGE_HEIGHT_EXP	5 /* 1024 = 2^5 * 2^5 */
+#define VRFB_PAGE_WIDTH		(1 << VRFB_PAGE_WIDTH_EXP)
+#define VRFB_PAGE_HEIGHT	(1 << VRFB_PAGE_HEIGHT_EXP)
+#define SMS_IMAGEHEIGHT_OFFSET	16
+#define SMS_IMAGEWIDTH_OFFSET	0
+#define SMS_PH_OFFSET		8
+#define SMS_PW_OFFSET		4
+#define SMS_PS_OFFSET		0
+
+#define VRFB_NUM_CTXS 12
+/* bitmap of reserved contexts */
+static unsigned long ctx_map;
+
+static DEFINE_MUTEX(ctx_lock);
+
+/*
+ * Access to this happens from client drivers or the PM core after wake-up.
+ * For the first case we require locking at the driver level, for the second
+ * we don't need locking, since no drivers will run until after the wake-up
+ * has finished.
+ */
+static struct {
+	u32 physical_ba;
+	u32 control;
+	u32 size;
+} vrfb_hw_context[VRFB_NUM_CTXS];
+
+static inline void restore_hw_context(int ctx)
+{
+	omap2_sms_write_rot_control(vrfb_hw_context[ctx].control, ctx);
+	omap2_sms_write_rot_size(vrfb_hw_context[ctx].size, ctx);
+	omap2_sms_write_rot_physical_ba(vrfb_hw_context[ctx].physical_ba, ctx);
+}
+
+static u32 get_image_width_roundup(u16 width, u8 bytespp)
+{
+	unsigned long stride = width * bytespp;
+	unsigned long ceil_pages_per_stride = (stride / VRFB_PAGE_WIDTH) +
+		(stride % VRFB_PAGE_WIDTH != 0);
+
+	return ceil_pages_per_stride * VRFB_PAGE_WIDTH / bytespp;
+}
+
+/*
+ * This the extra space needed in the VRFB physical area for VRFB to safely wrap
+ * any memory accesses to the invisible part of the virtual view to the physical
+ * area.
+ */
+static inline u32 get_extra_physical_size(u16 image_width_roundup, u8 bytespp)
+{
+	return (OMAP_VRFB_LINE_LEN - image_width_roundup) * VRFB_PAGE_HEIGHT *
+		bytespp;
+}
+
+void omap_vrfb_restore_context(void)
+{
+	int i;
+	unsigned long map = ctx_map;
+
+	for (i = ffs(map); i; i = ffs(map)) {
+		/* i=1..32 */
+		i--;
+		map &= ~(1 << i);
+		restore_hw_context(i);
+	}
+}
+
+void omap_vrfb_adjust_size(u16 *width, u16 *height,
+		u8 bytespp)
+{
+	*width = ALIGN(*width * bytespp, VRFB_PAGE_WIDTH) / bytespp;
+	*height = ALIGN(*height, VRFB_PAGE_HEIGHT);
+}
+EXPORT_SYMBOL(omap_vrfb_adjust_size);
+
+u32 omap_vrfb_min_phys_size(u16 width, u16 height, u8 bytespp)
+{
+	unsigned long image_width_roundup = get_image_width_roundup(width,
+		bytespp);
+
+	if (image_width_roundup > OMAP_VRFB_LINE_LEN)
+		return 0;
+
+	return (width * height * bytespp) + get_extra_physical_size(
+		image_width_roundup, bytespp);
+}
+EXPORT_SYMBOL(omap_vrfb_min_phys_size);
+
+u16 omap_vrfb_max_height(u32 phys_size, u16 width, u8 bytespp)
+{
+	unsigned long image_width_roundup = get_image_width_roundup(width,
+		bytespp);
+	unsigned long height;
+	unsigned long extra;
+
+	if (image_width_roundup > OMAP_VRFB_LINE_LEN)
+		return 0;
+
+	extra = get_extra_physical_size(image_width_roundup, bytespp);
+
+	if (phys_size < extra)
+		return 0;
+
+	height = (phys_size - extra) / (width * bytespp);
+
+	/* Virtual views provided by VRFB are limited to 2048x2048. */
+	return min_t(unsigned long, height, 2048);
+}
+EXPORT_SYMBOL(omap_vrfb_max_height);
+
+void omap_vrfb_setup(struct vrfb *vrfb, unsigned long paddr,
+		u16 width, u16 height,
+		unsigned bytespp, bool yuv_mode)
+{
+	unsigned pixel_size_exp;
+	u16 vrfb_width;
+	u16 vrfb_height;
+	u8 ctx = vrfb->context;
+	u32 size;
+	u32 control;
+
+	DBG("omapfb_set_vrfb(%d, %lx, %dx%d, %d, %d)\n", ctx, paddr,
+			width, height, bytespp, yuv_mode);
+
+	/* For YUV2 and UYVY modes VRFB needs to handle pixels a bit
+	 * differently. See TRM. */
+	if (yuv_mode) {
+		bytespp *= 2;
+		width /= 2;
+	}
+
+	if (bytespp == 4)
+		pixel_size_exp = 2;
+	else if (bytespp == 2)
+		pixel_size_exp = 1;
+	else
+		BUG();
+
+	vrfb_width = ALIGN(width * bytespp, VRFB_PAGE_WIDTH) / bytespp;
+	vrfb_height = ALIGN(height, VRFB_PAGE_HEIGHT);
+
+	DBG("vrfb w %u, h %u bytespp %d\n", vrfb_width, vrfb_height, bytespp);
+
+	size  = vrfb_width << SMS_IMAGEWIDTH_OFFSET;
+	size |= vrfb_height << SMS_IMAGEHEIGHT_OFFSET;
+
+	control  = pixel_size_exp << SMS_PS_OFFSET;
+	control |= VRFB_PAGE_WIDTH_EXP  << SMS_PW_OFFSET;
+	control |= VRFB_PAGE_HEIGHT_EXP << SMS_PH_OFFSET;
+
+	vrfb_hw_context[ctx].physical_ba = paddr;
+	vrfb_hw_context[ctx].size = size;
+	vrfb_hw_context[ctx].control = control;
+
+	omap2_sms_write_rot_physical_ba(paddr, ctx);
+	omap2_sms_write_rot_size(size, ctx);
+	omap2_sms_write_rot_control(control, ctx);
+
+	DBG("vrfb offset pixels %d, %d\n",
+			vrfb_width - width, vrfb_height - height);
+
+	vrfb->xres = width;
+	vrfb->yres = height;
+	vrfb->xoffset = vrfb_width - width;
+	vrfb->yoffset = vrfb_height - height;
+	vrfb->bytespp = bytespp;
+	vrfb->yuv_mode = yuv_mode;
+}
+EXPORT_SYMBOL(omap_vrfb_setup);
+
+int omap_vrfb_map_angle(struct vrfb *vrfb, u16 height, u8 rot)
+{
+	unsigned long size = height * OMAP_VRFB_LINE_LEN * vrfb->bytespp;
+
+	vrfb->vaddr[rot] = ioremap_wc(vrfb->paddr[rot], size);
+
+	if (!vrfb->vaddr[rot]) {
+		printk(KERN_ERR "vrfb: ioremap failed\n");
+		return -ENOMEM;
+	}
+
+	DBG("ioremapped vrfb area %d of size %lu into %p\n", rot, size,
+		vrfb->vaddr[rot]);
+
+	return 0;
+}
+EXPORT_SYMBOL(omap_vrfb_map_angle);
+
+void omap_vrfb_release_ctx(struct vrfb *vrfb)
+{
+	int rot;
+	int ctx = vrfb->context;
+
+	if (ctx == 0xff)
+		return;
+
+	DBG("release ctx %d\n", ctx);
+
+	mutex_lock(&ctx_lock);
+
+	BUG_ON(!(ctx_map & (1 << ctx)));
+
+	clear_bit(ctx, &ctx_map);
+
+	for (rot = 0; rot < 4; ++rot) {
+		if (vrfb->paddr[rot]) {
+			release_mem_region(vrfb->paddr[rot], OMAP_VRFB_SIZE);
+			vrfb->paddr[rot] = 0;
+		}
+	}
+
+	vrfb->context = 0xff;
+
+	mutex_unlock(&ctx_lock);
+}
+EXPORT_SYMBOL(omap_vrfb_release_ctx);
+
+int omap_vrfb_request_ctx(struct vrfb *vrfb)
+{
+	int rot;
+	u32 paddr;
+	u8 ctx;
+	int r;
+
+	DBG("request ctx\n");
+
+	mutex_lock(&ctx_lock);
+
+	for (ctx = 0; ctx < VRFB_NUM_CTXS; ++ctx)
+		if ((ctx_map & (1 << ctx)) == 0)
+			break;
+
+	if (ctx == VRFB_NUM_CTXS) {
+		pr_err("vrfb: no free contexts\n");
+		r = -EBUSY;
+		goto out;
+	}
+
+	DBG("found free ctx %d\n", ctx);
+
+	set_bit(ctx, &ctx_map);
+
+	memset(vrfb, 0, sizeof(*vrfb));
+
+	vrfb->context = ctx;
+
+	for (rot = 0; rot < 4; ++rot) {
+		paddr = SMS_ROT_VIRT_BASE(ctx, rot);
+		if (!request_mem_region(paddr, OMAP_VRFB_SIZE, "vrfb")) {
+			pr_err("vrfb: failed to reserve VRFB "
+					"area for ctx %d, rotation %d\n",
+					ctx, rot * 90);
+			omap_vrfb_release_ctx(vrfb);
+			r = -ENOMEM;
+			goto out;
+		}
+
+		vrfb->paddr[rot] = paddr;
+
+		DBG("VRFB %d/%d: %lx\n", ctx, rot*90, vrfb->paddr[rot]);
+	}
+
+	r = 0;
+out:
+	mutex_unlock(&ctx_lock);
+	return r;
+}
+EXPORT_SYMBOL(omap_vrfb_request_ctx);