drm/i915: add FIFO watermark support

This patch from jbarnes and myself adds FIFO watermark control to the
driver.  This is needed for both power saving features on new platforms
with the so-called "big FIFO" and for controlling FIFO allocation
between pipes in multi-head configurations.

It's also necessary infrastructure to support things like framebuffer
compression and configuration supportability checks (i.e. checking a
configuration against available bandwidth).

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 423 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 73e7b9cecac8..a84ac05ef048 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -25,6 +25,7 @@
  */
 
 #include <linux/i2c.h>
+#include <linux/kernel.h>
 #include "drmP.h"
 #include "intel_drv.h"
 #include "i915_drm.h"
@@ -34,6 +35,7 @@
 #include "drm_crtc_helper.h"
 
 bool intel_pipe_has_type (struct drm_crtc *crtc, int type);
+static void intel_update_watermarks(struct drm_device *dev);
 
 typedef struct {
     /* given values */
@@ -1005,7 +1007,7 @@ static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	int pipe = intel_crtc->pipe;
-	int plane = intel_crtc->pipe;
+	int plane = intel_crtc->plane;
 	int pch_dpll_reg = (pipe == 0) ? PCH_DPLL_A : PCH_DPLL_B;
 	int pipeconf_reg = (pipe == 0) ? PIPEACONF : PIPEBCONF;
 	int dspcntr_reg = (plane == 0) ? DSPACNTR : DSPBCNTR;
@@ -1335,8 +1337,10 @@ static void i9xx_crtc_dpms(struct drm_crtc *crtc, int mode)
 
 		/* Give the overlay scaler a chance to enable if it's on this pipe */
 		//intel_crtc_dpms_video(crtc, true); TODO
+		intel_update_watermarks(dev);
 	break;
 	case DRM_MODE_DPMS_OFF:
+		intel_update_watermarks(dev);
 		/* Give the overlay scaler a chance to disable if it's on this pipe */
 		//intel_crtc_dpms_video(crtc, FALSE); TODO
 
@@ -1515,7 +1519,6 @@ static int intel_get_core_clock_speed(struct drm_device *dev)
 	return 0; /* Silence gcc warning */
 }
 
-
 /**
  * Return the pipe currently connected to the panel fitter,
  * or -1 if the panel fitter is not present or not in use
@@ -1585,6 +1588,420 @@ igdng_compute_m_n(int bytes_per_pixel, int nlanes,
 }
 
 
+struct intel_watermark_params {
+	unsigned long fifo_size;
+	unsigned long max_wm;
+	unsigned long default_wm;
+	unsigned long guard_size;
+	unsigned long cacheline_size;
+};
+
+/* IGD has different values for various configs */
+static struct intel_watermark_params igd_display_wm = {
+	IGD_DISPLAY_FIFO,
+	IGD_MAX_WM,
+	IGD_DFT_WM,
+	IGD_GUARD_WM,
+	IGD_FIFO_LINE_SIZE
+};
+static struct intel_watermark_params igd_display_hplloff_wm = {
+	IGD_DISPLAY_FIFO,
+	IGD_MAX_WM,
+	IGD_DFT_HPLLOFF_WM,
+	IGD_GUARD_WM,
+	IGD_FIFO_LINE_SIZE
+};
+static struct intel_watermark_params igd_cursor_wm = {
+	IGD_CURSOR_FIFO,
+	IGD_CURSOR_MAX_WM,
+	IGD_CURSOR_DFT_WM,
+	IGD_CURSOR_GUARD_WM,
+	IGD_FIFO_LINE_SIZE,
+};
+static struct intel_watermark_params igd_cursor_hplloff_wm = {
+	IGD_CURSOR_FIFO,
+	IGD_CURSOR_MAX_WM,
+	IGD_CURSOR_DFT_WM,
+	IGD_CURSOR_GUARD_WM,
+	IGD_FIFO_LINE_SIZE
+};
+static struct intel_watermark_params i945_wm_info = {
+	I915_FIFO_LINE_SIZE,
+	I915_MAX_WM,
+	1,
+	0,
+	IGD_FIFO_LINE_SIZE
+};
+static struct intel_watermark_params i915_wm_info = {
+	I945_FIFO_SIZE,
+	I915_MAX_WM,
+	1,
+	0,
+	I915_FIFO_LINE_SIZE
+};
+static struct intel_watermark_params i855_wm_info = {
+	I855GM_FIFO_SIZE,
+	I915_MAX_WM,
+	1,
+	0,
+	I830_FIFO_LINE_SIZE
+};
+static struct intel_watermark_params i830_wm_info = {
+	I830_FIFO_SIZE,
+	I915_MAX_WM,
+	1,
+	0,
+	I830_FIFO_LINE_SIZE
+};
+
+static unsigned long intel_calculate_wm(unsigned long clock_in_khz,
+					struct intel_watermark_params *wm,
+					int pixel_size,
+					unsigned long latency_ns)
+{
+	unsigned long bytes_required, wm_size;
+
+	bytes_required = (clock_in_khz * pixel_size * latency_ns) / 1000000;
+	bytes_required /= wm->cacheline_size;
+	wm_size = wm->fifo_size - bytes_required - wm->guard_size;
+
+	if (wm_size > wm->max_wm)
+		wm_size = wm->max_wm;
+	if (wm_size == 0)
+		wm_size = wm->default_wm;
+	return wm_size;
+}
+
+struct cxsr_latency {
+	int is_desktop;
+	unsigned long fsb_freq;
+	unsigned long mem_freq;
+	unsigned long display_sr;
+	unsigned long display_hpll_disable;
+	unsigned long cursor_sr;
+	unsigned long cursor_hpll_disable;
+};
+
+static struct cxsr_latency cxsr_latency_table[] = {
+	{1, 800, 400, 3382, 33382, 3983, 33983},    /* DDR2-400 SC */
+	{1, 800, 667, 3354, 33354, 3807, 33807},    /* DDR2-667 SC */
+	{1, 800, 800, 3347, 33347, 3763, 33763},    /* DDR2-800 SC */
+
+	{1, 667, 400, 3400, 33400, 4021, 34021},    /* DDR2-400 SC */
+	{1, 667, 667, 3372, 33372, 3845, 33845},    /* DDR2-667 SC */
+	{1, 667, 800, 3386, 33386, 3822, 33822},    /* DDR2-800 SC */
+
+	{1, 400, 400, 3472, 33472, 4173, 34173},    /* DDR2-400 SC */
+	{1, 400, 667, 3443, 33443, 3996, 33996},    /* DDR2-667 SC */
+	{1, 400, 800, 3430, 33430, 3946, 33946},    /* DDR2-800 SC */
+
+	{0, 800, 400, 3438, 33438, 4065, 34065},    /* DDR2-400 SC */
+	{0, 800, 667, 3410, 33410, 3889, 33889},    /* DDR2-667 SC */
+	{0, 800, 800, 3403, 33403, 3845, 33845},    /* DDR2-800 SC */
+
+	{0, 667, 400, 3456, 33456, 4103, 34106},    /* DDR2-400 SC */
+	{0, 667, 667, 3428, 33428, 3927, 33927},    /* DDR2-667 SC */
+	{0, 667, 800, 3443, 33443, 3905, 33905},    /* DDR2-800 SC */
+
+	{0, 400, 400, 3528, 33528, 4255, 34255},    /* DDR2-400 SC */
+	{0, 400, 667, 3500, 33500, 4079, 34079},    /* DDR2-667 SC */
+	{0, 400, 800, 3487, 33487, 4029, 34029},    /* DDR2-800 SC */
+};
+
+static struct cxsr_latency *intel_get_cxsr_latency(int is_desktop, int fsb,
+						   int mem)
+{
+	int i;
+	struct cxsr_latency *latency;
+
+	if (fsb == 0 || mem == 0)
+		return NULL;
+
+	for (i = 0; i < ARRAY_SIZE(cxsr_latency_table); i++) {
+		latency = &cxsr_latency_table[i];
+		if (is_desktop == latency->is_desktop &&
+			fsb == latency->fsb_freq && mem == latency->mem_freq)
+			break;
+	}
+	if (i >= ARRAY_SIZE(cxsr_latency_table)) {
+		DRM_DEBUG("Unknown FSB/MEM found, disable CxSR\n");
+		return NULL;
+	}
+	return latency;
+}
+
+static void igd_disable_cxsr(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 reg;
+
+	/* deactivate cxsr */
+	reg = I915_READ(DSPFW3);
+	reg &= ~(IGD_SELF_REFRESH_EN);
+	I915_WRITE(DSPFW3, reg);
+	DRM_INFO("Big FIFO is disabled\n");
+}
+
+static void igd_enable_cxsr(struct drm_device *dev, unsigned long clock,
+			    int pixel_size)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 reg;
+	unsigned long wm;
+	struct cxsr_latency *latency;
+
+	latency = intel_get_cxsr_latency(IS_IGDG(dev), dev_priv->fsb_freq,
+		dev_priv->mem_freq);
+	if (!latency) {
+		DRM_DEBUG("Unknown FSB/MEM found, disable CxSR\n");
+		igd_disable_cxsr(dev);
+		return;
+	}
+
+	/* Display SR */
+	wm = intel_calculate_wm(clock, &igd_display_wm, pixel_size,
+				latency->display_sr);
+	reg = I915_READ(DSPFW1);
+	reg &= 0x7fffff;
+	reg |= wm << 23;
+	I915_WRITE(DSPFW1, reg);
+	DRM_DEBUG("DSPFW1 register is %x\n", reg);
+
+	/* cursor SR */
+	wm = intel_calculate_wm(clock, &igd_cursor_wm, pixel_size,
+				latency->cursor_sr);
+	reg = I915_READ(DSPFW3);
+	reg &= ~(0x3f << 24);
+	reg |= (wm & 0x3f) << 24;
+	I915_WRITE(DSPFW3, reg);
+
+	/* Display HPLL off SR */
+	wm = intel_calculate_wm(clock, &igd_display_hplloff_wm,
+		latency->display_hpll_disable, I915_FIFO_LINE_SIZE);
+	reg = I915_READ(DSPFW3);
+	reg &= 0xfffffe00;
+	reg |= wm & 0x1ff;
+	I915_WRITE(DSPFW3, reg);
+
+	/* cursor HPLL off SR */
+	wm = intel_calculate_wm(clock, &igd_cursor_hplloff_wm, pixel_size,
+				latency->cursor_hpll_disable);
+	reg = I915_READ(DSPFW3);
+	reg &= ~(0x3f << 16);
+	reg |= (wm & 0x3f) << 16;
+	I915_WRITE(DSPFW3, reg);
+	DRM_DEBUG("DSPFW3 register is %x\n", reg);
+
+	/* activate cxsr */
+	reg = I915_READ(DSPFW3);
+	reg |= IGD_SELF_REFRESH_EN;
+	I915_WRITE(DSPFW3, reg);
+
+	DRM_INFO("Big FIFO is enabled\n");
+
+	return;
+}
+
+const static int latency_ns = 5000; /* default for non-igd platforms */
+
+
+static void i965_update_wm(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	DRM_DEBUG("Setting FIFO watermarks - A: 8, B: 8, C: 8, SR 8\n");
+
+	/* 965 has limitations... */
+	I915_WRITE(DSPFW1, (8 << 16) | (8 << 8) | (8 << 0));
+	I915_WRITE(DSPFW2, (8 << 8) | (8 << 0));
+}
+
+static void i9xx_update_wm(struct drm_device *dev, int planea_clock,
+			   int planeb_clock, int sr_hdisplay, int pixel_size)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	uint32_t fwater_lo = I915_READ(FW_BLC) & MM_FIFO_WATERMARK;
+	uint32_t fwater_hi = I915_READ(FW_BLC2) & LM_FIFO_WATERMARK;
+	int bsize, asize, cwm, bwm = 1, awm = 1, srwm = 1;
+	uint32_t dsparb = I915_READ(DSPARB);
+	int planea_entries, planeb_entries;
+	struct intel_watermark_params *wm_params;
+	unsigned long line_time_us;
+	int sr_clock, sr_entries = 0;
+
+	if (IS_I965GM(dev) || IS_I945GM(dev))
+		wm_params = &i945_wm_info;
+	else if (IS_I9XX(dev))
+		wm_params = &i915_wm_info;
+	else
+		wm_params = &i855_wm_info;
+
+	planea_entries = intel_calculate_wm(planea_clock, wm_params,
+					    pixel_size, latency_ns);
+	planeb_entries = intel_calculate_wm(planeb_clock, wm_params,
+					    pixel_size, latency_ns);
+
+	DRM_DEBUG("FIFO entries - A: %d, B: %d\n", planea_entries,
+		  planeb_entries);
+
+	if (IS_I9XX(dev)) {
+		asize = dsparb & 0x7f;
+		bsize = (dsparb >> DSPARB_CSTART_SHIFT) & 0x7f;
+	} else {
+		asize = dsparb & 0x1ff;
+		bsize = (dsparb >> DSPARB_BEND_SHIFT) & 0x1ff;
+	}
+	DRM_DEBUG("FIFO size - A: %d, B: %d\n", asize, bsize);
+
+	/* Two extra entries for padding */
+	awm = asize - (planea_entries + 2);
+	bwm = bsize - (planeb_entries + 2);
+
+	/* Sanity check against potentially bad FIFO allocations */
+	if (awm <= 0) {
+		/* pipe is on but has too few FIFO entries */
+		if (planea_entries != 0)
+			DRM_DEBUG("plane A needs more FIFO entries\n");
+		awm = 1;
+	}
+	if (bwm <= 0) {
+		if (planeb_entries != 0)
+			DRM_DEBUG("plane B needs more FIFO entries\n");
+		bwm = 1;
+	}
+
+	/*
+	 * Overlay gets an aggressive default since video jitter is bad.
+	 */
+	cwm = 2;
+
+	/* Calc sr entries for one pipe configs */
+	if (!planea_clock || !planeb_clock) {
+		sr_clock = planea_clock ? planea_clock : planeb_clock;
+		line_time_us = (sr_hdisplay * 1000) / sr_clock;
+		sr_entries = (((latency_ns / line_time_us) + 1) * pixel_size *
+			      sr_hdisplay) / 1000;
+		sr_entries = roundup(sr_entries / wm_params->cacheline_size, 1);
+		if (sr_entries < wm_params->fifo_size)
+			srwm = wm_params->fifo_size - sr_entries;
+	}
+
+	DRM_DEBUG("Setting FIFO watermarks - A: %d, B: %d, C: %d, SR %d\n",
+		  awm, bwm, cwm, srwm);
+
+	fwater_lo = fwater_lo | ((bwm & 0x3f) << 16) | (awm & 0x3f);
+	fwater_hi = fwater_hi | (cwm & 0x1f);
+
+	I915_WRITE(FW_BLC, fwater_lo);
+	I915_WRITE(FW_BLC2, fwater_hi);
+	if (IS_I9XX(dev))
+		I915_WRITE(FW_BLC_SELF, FW_BLC_SELF_EN | (srwm & 0x3f));
+}
+
+static void i830_update_wm(struct drm_device *dev, int planea_clock,
+			   int pixel_size)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	uint32_t dsparb = I915_READ(DSPARB);
+	uint32_t fwater_lo = I915_READ(FW_BLC) & MM_FIFO_WATERMARK;
+	unsigned int asize, awm;
+	int planea_entries;
+
+	planea_entries = intel_calculate_wm(planea_clock, &i830_wm_info,
+					    pixel_size, latency_ns);
+
+	asize = dsparb & 0x7f;
+
+	awm = asize - planea_entries;
+
+	fwater_lo = fwater_lo | awm;
+
+	I915_WRITE(FW_BLC, fwater_lo);
+}
+
+/**
+ * intel_update_watermarks - update FIFO watermark values based on current modes
+ *
+ * Calculate watermark values for the various WM regs based on current mode
+ * and plane configuration.
+ *
+ * There are several cases to deal with here:
+ *   - normal (i.e. non-self-refresh)
+ *   - self-refresh (SR) mode
+ *   - lines are large relative to FIFO size (buffer can hold up to 2)
+ *   - lines are small relative to FIFO size (buffer can hold more than 2
+ *     lines), so need to account for TLB latency
+ *
+ *   The normal calculation is:
+ *     watermark = dotclock * bytes per pixel * latency
+ *   where latency is platform & configuration dependent (we assume pessimal
+ *   values here).
+ *
+ *   The SR calculation is:
+ *     watermark = (trunc(latency/line time)+1) * surface width *
+ *       bytes per pixel
+ *   where
+ *     line time = htotal / dotclock
+ *   and latency is assumed to be high, as above.
+ *
+ * The final value programmed to the register should always be rounded up,
+ * and include an extra 2 entries to account for clock crossings.
+ *
+ * We don't use the sprite, so we can ignore that.  And on Crestline we have
+ * to set the non-SR watermarks to 8.
+  */
+static void intel_update_watermarks(struct drm_device *dev)
+{
+	struct drm_crtc *crtc;
+	struct intel_crtc *intel_crtc;
+	int sr_hdisplay = 0;
+	unsigned long planea_clock = 0, planeb_clock = 0, sr_clock = 0;
+	int enabled = 0, pixel_size = 0;
+
+	if (DSPARB_HWCONTROL(dev))
+		return;
+
+	/* Get the clock config from both planes */
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		intel_crtc = to_intel_crtc(crtc);
+		if (crtc->enabled) {
+			enabled++;
+			if (intel_crtc->plane == 0) {
+				DRM_DEBUG("plane A (pipe %d) clock: %d\n",
+					  intel_crtc->pipe, crtc->mode.clock);
+				planea_clock = crtc->mode.clock;
+			} else {
+				DRM_DEBUG("plane B (pipe %d) clock: %d\n",
+					  intel_crtc->pipe, crtc->mode.clock);
+				planeb_clock = crtc->mode.clock;
+			}
+			sr_hdisplay = crtc->mode.hdisplay;
+			sr_clock = crtc->mode.clock;
+			if (crtc->fb)
+				pixel_size = crtc->fb->bits_per_pixel / 8;
+			else
+				pixel_size = 4; /* by default */
+		}
+	}
+
+	if (enabled <= 0)
+		return;
+
+	/* Single pipe configs can enable self refresh */
+	if (enabled == 1 && IS_IGD(dev))
+		igd_enable_cxsr(dev, sr_clock, pixel_size);
+	else if (IS_IGD(dev))
+		igd_disable_cxsr(dev);
+
+	if (IS_I965G(dev))
+		i965_update_wm(dev);
+	else if (IS_I9XX(dev) || IS_MOBILE(dev))
+		i9xx_update_wm(dev, planea_clock, planeb_clock, sr_hdisplay,
+			       pixel_size);
+	else
+		i830_update_wm(dev, planea_clock, pixel_size);
+}
+
 static int intel_crtc_mode_set(struct drm_crtc *crtc,
 			       struct drm_display_mode *mode,
 			       struct drm_display_mode *adjusted_mode,
@@ -1951,6 +2368,9 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
 
 	/* Flush the plane changes */
 	ret = intel_pipe_set_base(crtc, x, y, old_fb);
+
+	intel_update_watermarks(dev);
+
 	drm_vblank_post_modeset(dev, pipe);
 
 	return ret;
@@ -2439,6 +2859,7 @@ static void intel_crtc_init(struct drm_device *dev, int pipe)
 
 	drm_mode_crtc_set_gamma_size(&intel_crtc->base, 256);
 	intel_crtc->pipe = pipe;
+	intel_crtc->plane = pipe;
 	for (i = 0; i < 256; i++) {
 		intel_crtc->lut_r[i] = i;
 		intel_crtc->lut_g[i] = i;