From c8d4a56082eebabbf96ddb86238808c30124f06b Mon Sep 17 00:00:00 2001
From: Linus Walleij <linus.walleij@linaro.org>
Date: Tue, 17 Dec 2019 16:09:59 +0100
Subject: drm/mcde: Some fixes to handling video mode
Git-commit: c8d4a56082eebabbf96ddb86238808c30124f06b
Patch-mainline: v5.6-rc1
References: bsc#1152472
The video DSI mode had not really been tested. These fixes makes
it more likely to work on real hardware:
- Put the active width (x width) in the right bits and the VSA
(vertical sync active) in the right bits (those were swapped).
- Calculate the packet sizes in bytes as in the vendor driver,
rather than in bits. Test the calculations agains a
spreadsheet and confirmed by debug prints to be reasonable.
- Also verified the register values with relative confidence
to register dumps from the Samsung GT-I8190 boot loader
graphics. We are not identical but not off by far either.
- Error out if the current mode and refresh frequency doesn't
work out. (In the future we may simply want to scale down
the vrefresh.)
- Handle negative result in front/back/sync packages and fall
back to zero like in the vendor driver.
- Put in lots of clarifying comments and references to the
documentation where the code is hard to understand.
- Set the DSI_VID_VCA_SETTING2 field
DSI_VID_VCA_SETTING2_MAX_LINE_LIMIT to blkline_pck - 6 as in
the vendor driver and mask the field properly.
- Set the DSI_VID_VCA_SETTING1 field
DSI_VID_VCA_SETTING1_MAX_BURST_LIMIT to blkeol_pck - 6 to
blkeol_duration - 6 as in the vendor driver.
Cc: Stephan Gerhold <stephan@gerhold.net>
Fixes: 5fc537bfd000 ("drm/mcde: Add new driver for ST-Ericsson MCDE")
Link: https://patchwork.freedesktop.org/patch/msgid/20191217150959.17215-1-linus.walleij@linaro.org
Reviewed-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
drivers/gpu/drm/mcde/mcde_dsi.c | 238 ++++++++++++++++++++++++++++-------
drivers/gpu/drm/mcde/mcde_dsi_regs.h | 1
2 files changed, 192 insertions(+), 47 deletions(-)
--- a/drivers/gpu/drm/mcde/mcde_dsi.c
+++ b/drivers/gpu/drm/mcde/mcde_dsi.c
@@ -365,13 +365,14 @@ void mcde_dsi_te_request(struct mipi_dsi
static void mcde_dsi_setup_video_mode(struct mcde_dsi *d,
const struct drm_display_mode *mode)
{
- u8 bpp = mipi_dsi_pixel_format_to_bpp(d->mdsi->format);
+ /* cpp, characters per pixel, number of bytes per pixel */
+ u8 cpp = mipi_dsi_pixel_format_to_bpp(d->mdsi->format) / 8;
+ u64 pclk;
u64 bpl;
- u32 hfp;
- u32 hbp;
- u32 hsa;
+ int hfp;
+ int hbp;
+ int hsa;
u32 blkline_pck, line_duration;
- u32 blkeol_pck, blkeol_duration;
u32 val;
val = 0;
@@ -408,11 +409,21 @@ static void mcde_dsi_setup_video_mode(st
return;
}
- /* TODO: TVG could be enabled here */
+ /* TODO: TVG (test video generator) could be enabled here */
- /* Send blanking packet */
+ /*
+ * During vertical blanking: go to LP mode
+ * Like with the EOL setting, if this is not set, the EOL area will be
+ * filled with NULL or blanking packets in the vblank area.
+ * FIXME: some Samsung phones and display panels such as s6e63m0 use
+ * DSI_VID_MAIN_CTL_REG_BLKLINE_MODE_BLANKING here instead,
+ * figure out how to properly configure that from the panel.
+ */
val |= DSI_VID_MAIN_CTL_REG_BLKLINE_MODE_LP_0;
- /* Send EOL packet */
+ /*
+ * During EOL: go to LP mode. If this is not set, the EOL area will be
+ * filled with NULL or blanking packets.
+ */
val |= DSI_VID_MAIN_CTL_REG_BLKEOL_MODE_LP_0;
/* Recovery mode 1 */
val |= 1 << DSI_VID_MAIN_CTL_RECOVERY_MODE_SHIFT;
@@ -420,13 +431,13 @@ static void mcde_dsi_setup_video_mode(st
writel(val, d->regs + DSI_VID_MAIN_CTL);
/* Vertical frame parameters are pretty straight-forward */
- val = mode->vdisplay << DSI_VID_VSIZE_VSA_LENGTH_SHIFT;
+ val = mode->vdisplay << DSI_VID_VSIZE_VACT_LENGTH_SHIFT;
/* vertical front porch */
val |= (mode->vsync_start - mode->vdisplay)
<< DSI_VID_VSIZE_VFP_LENGTH_SHIFT;
/* vertical sync active */
val |= (mode->vsync_end - mode->vsync_start)
- << DSI_VID_VSIZE_VACT_LENGTH_SHIFT;
+ << DSI_VID_VSIZE_VSA_LENGTH_SHIFT;
/* vertical back porch */
val |= (mode->vtotal - mode->vsync_end)
<< DSI_VID_VSIZE_VBP_LENGTH_SHIFT;
@@ -434,36 +445,54 @@ static void mcde_dsi_setup_video_mode(st
/*
* Horizontal frame parameters:
- * horizontal resolution is given in pixels and must be re-calculated
- * into bytes since this is what the hardware expects.
+ * horizontal resolution is given in pixels but must be re-calculated
+ * into bytes since this is what the hardware expects, these registers
+ * define the payload size of the packet.
+ *
+ * hfp = horizontal front porch in bytes
+ * hbp = horizontal back porch in bytes
+ * hsa = horizontal sync active in bytes
*
* 6 + 2 is HFP header + checksum
*/
- hfp = (mode->hsync_start - mode->hdisplay) * bpp - 6 - 2;
+ hfp = (mode->hsync_start - mode->hdisplay) * cpp - 6 - 2;
if (d->mdsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE) {
/*
+ * Use sync pulse for sync: explicit HSA time
* 6 is HBP header + checksum
* 4 is RGB header + checksum
*/
- hbp = (mode->htotal - mode->hsync_end) * bpp - 4 - 6;
+ hbp = (mode->htotal - mode->hsync_end) * cpp - 4 - 6;
/*
* 6 is HBP header + checksum
* 4 is HSW packet bytes
* 4 is RGB header + checksum
*/
- hsa = (mode->hsync_end - mode->hsync_start) * bpp - 4 - 4 - 6;
+ hsa = (mode->hsync_end - mode->hsync_start) * cpp - 4 - 4 - 6;
} else {
/*
- * HBP includes both back porch and sync
+ * Use event for sync: HBP includes both back porch and sync
* 6 is HBP header + checksum
* 4 is HSW packet bytes
* 4 is RGB header + checksum
*/
- hbp = (mode->htotal - mode->hsync_start) * bpp - 4 - 4 - 6;
- /* HSA is not considered in this mode and set to 0 */
+ hbp = (mode->htotal - mode->hsync_start) * cpp - 4 - 4 - 6;
+ /* HSA is not present in this mode and set to 0 */
hsa = 0;
}
- dev_dbg(d->dev, "hfp: %u, hbp: %u, hsa: %u\n",
+ if (hfp < 0) {
+ dev_info(d->dev, "hfp negative, set to 0\n");
+ hfp = 0;
+ }
+ if (hbp < 0) {
+ dev_info(d->dev, "hbp negative, set to 0\n");
+ hbp = 0;
+ }
+ if (hsa < 0) {
+ dev_info(d->dev, "hsa negative, set to 0\n");
+ hsa = 0;
+ }
+ dev_dbg(d->dev, "hfp: %u, hbp: %u, hsa: %u bytes\n",
hfp, hbp, hsa);
/* Frame parameters: horizontal sync active */
@@ -474,70 +503,185 @@ static void mcde_dsi_setup_video_mode(st
val |= hfp << DSI_VID_HSIZE1_HFP_LENGTH_SHIFT;
writel(val, d->regs + DSI_VID_HSIZE1);
- /* RGB data length (bytes on one scanline) */
- val = mode->hdisplay * (bpp / 8);
+ /* RGB data length (visible bytes on one scanline) */
+ val = mode->hdisplay * cpp;
writel(val, d->regs + DSI_VID_HSIZE2);
+ dev_dbg(d->dev, "RGB length, visible area on a line: %u bytes\n", val);
- /* TODO: further adjustments for TVG mode here */
+ /*
+ * Calculate the time between two pixels in picoseconds using
+ * the supplied refresh rate and total resolution including
+ * porches and sync.
+ */
+ /* (ps/s) / (pixels/s) = ps/pixels */
+ pclk = DIV_ROUND_UP_ULL(1000000000000,
+ (mode->vrefresh * mode->htotal * mode->vtotal));
+ dev_dbg(d->dev, "picoseconds between two pixels: %llu\n",
+ pclk);
/*
- * EOL packet length from bits per line calculations: pixel clock
- * is given in kHz, calculate the time between two pixels in
- * picoseconds.
+ * How many bytes per line will this update frequency yield?
+ *
+ * Calculate the number of picoseconds for one scanline (1), then
+ * divide by 1000000000000 (2) to get in pixels per second we
+ * want to output.
+ *
+ * Multiply with number of bytes per second at this video display
+ * frequency (3) to get number of bytes transferred during this
+ * time. Notice that we use the frequency the display wants,
+ * not what we actually get from the DSI PLL, which is hs_freq.
+ *
+ * These arithmetics are done in a different order to avoid
+ * overflow.
*/
- bpl = mode->clock * mode->htotal;
- bpl *= (d->hs_freq / 8);
- do_div(bpl, 1000000); /* microseconds */
- do_div(bpl, 1000000); /* seconds */
+ bpl = pclk * mode->htotal; /* (1) picoseconds per line */
+ dev_dbg(d->dev, "picoseconds per line: %llu\n", bpl);
+ /* Multiply with bytes per second (3) */
+ bpl *= (d->mdsi->hs_rate / 8);
+ /* Pixels per second (2) */
+ bpl = DIV_ROUND_DOWN_ULL(bpl, 1000000); /* microseconds */
+ bpl = DIV_ROUND_DOWN_ULL(bpl, 1000000); /* seconds */
+ /* parallel transactions in all lanes */
bpl *= d->mdsi->lanes;
- dev_dbg(d->dev, "calculated bytes per line: %llu\n", bpl);
+ dev_dbg(d->dev,
+ "calculated bytes per line: %llu @ %d Hz with HS %lu Hz\n",
+ bpl, mode->vrefresh, d->mdsi->hs_rate);
+
/*
* 6 is header + checksum, header = 4 bytes, checksum = 2 bytes
* 4 is short packet for vsync/hsync
*/
if (d->mdsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE) {
- /* Fixme: isn't the hsync width in pixels? */
+ /* Set the event packet size to 0 (not used) */
+ writel(0, d->regs + DSI_VID_BLKSIZE1);
+ /*
+ * FIXME: isn't the hsync width in pixels? The porch and
+ * sync area size is in pixels here, but this -6
+ * seems to be for bytes. It looks like this in the vendor
+ * code though. Is it completely untested?
+ */
blkline_pck = bpl - (mode->hsync_end - mode->hsync_start) - 6;
val = blkline_pck << DSI_VID_BLKSIZE2_BLKLINE_PULSE_PCK_SHIFT;
writel(val, d->regs + DSI_VID_BLKSIZE2);
} else {
+ /* Set the sync pulse packet size to 0 (not used) */
+ writel(0, d->regs + DSI_VID_BLKSIZE2);
+ /* Specifying payload size in bytes (-4-6 from manual) */
blkline_pck = bpl - 4 - 6;
+ if (blkline_pck > 0x1FFF)
+ dev_err(d->dev, "blkline_pck too big %d bytes\n",
+ blkline_pck);
val = blkline_pck << DSI_VID_BLKSIZE1_BLKLINE_EVENT_PCK_SHIFT;
+ val &= DSI_VID_BLKSIZE1_BLKLINE_EVENT_PCK_MASK;
writel(val, d->regs + DSI_VID_BLKSIZE1);
}
- line_duration = (blkline_pck + 6) / d->mdsi->lanes;
- dev_dbg(d->dev, "line duration %u\n", line_duration);
+ /*
+ * The line duration is used to scale back the frequency from
+ * the max frequency supported by the HS clock to the desired
+ * update frequency in vrefresh.
+ */
+ line_duration = blkline_pck + 6;
+ /*
+ * The datasheet contains this complex condition to decreasing
+ * the line duration by 1 under very specific circumstances.
+ * Here we also imply that LP is used during burst EOL.
+ */
+ if (d->mdsi->lanes == 2 && (hsa & 0x01) && (hfp & 0x01)
+ && (d->mdsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST))
+ line_duration--;
+ line_duration = DIV_ROUND_CLOSEST(line_duration, d->mdsi->lanes);
+ dev_dbg(d->dev, "line duration %u bytes\n", line_duration);
val = line_duration << DSI_VID_DPHY_TIME_REG_LINE_DURATION_SHIFT;
/*
* This is the time to perform LP->HS on D-PHY
* FIXME: nowhere to get this from: DT property on the DSI?
+ * The manual says this is "system dependent".
+ * values like 48 and 72 seen in the vendor code.
*/
- val |= 0 << DSI_VID_DPHY_TIME_REG_WAKEUP_TIME_SHIFT;
+ val |= 48 << DSI_VID_DPHY_TIME_REG_WAKEUP_TIME_SHIFT;
writel(val, d->regs + DSI_VID_DPHY_TIME);
- /* Calculate block end of line */
- blkeol_pck = bpl - mode->hdisplay * bpp - 6;
- blkeol_duration = (blkeol_pck + 6) / d->mdsi->lanes;
- dev_dbg(d->dev, "blkeol pck: %u, duration: %u\n",
- blkeol_pck, blkeol_duration);
-
+ /*
+ * See the manual figure 657 page 2203 for understanding the impact
+ * of the different burst mode settings.
+ */
if (d->mdsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) {
- /* Set up EOL clock for burst mode */
+ int blkeol_pck, blkeol_duration;
+ /*
+ * Packet size at EOL for burst mode, this is only used
+ * if DSI_VID_MAIN_CTL_REG_BLKEOL_MODE_LP_0 is NOT set,
+ * but we instead send NULL or blanking packets at EOL.
+ * This is given in number of bytes.
+ *
+ * See the manual page 2198 for the 13 reg_blkeol_pck bits.
+ */
+ blkeol_pck = bpl - (mode->htotal * cpp) - 6;
+ if (blkeol_pck < 0) {
+ dev_err(d->dev, "video block does not fit on line!\n");
+ dev_err(d->dev,
+ "calculated bytes per line: %llu @ %d Hz\n",
+ bpl, mode->vrefresh);
+ dev_err(d->dev,
+ "bytes per line (blkline_pck) %u bytes\n",
+ blkline_pck);
+ dev_err(d->dev,
+ "blkeol_pck becomes %d bytes\n", blkeol_pck);
+ return;
+ }
+ dev_dbg(d->dev, "BLKEOL packet: %d bytes\n", blkeol_pck);
+
val = readl(d->regs + DSI_VID_BLKSIZE1);
+ val &= ~DSI_VID_BLKSIZE1_BLKEOL_PCK_MASK;
val |= blkeol_pck << DSI_VID_BLKSIZE1_BLKEOL_PCK_SHIFT;
writel(val, d->regs + DSI_VID_BLKSIZE1);
- writel(blkeol_pck, d->regs + DSI_VID_VCA_SETTING2);
-
- writel(blkeol_duration, d->regs + DSI_VID_PCK_TIME);
- writel(blkeol_duration - 6, d->regs + DSI_VID_VCA_SETTING1);
+ /* Use the same value for exact burst limit */
+ val = blkeol_pck <<
+ DSI_VID_VCA_SETTING2_EXACT_BURST_LIMIT_SHIFT;
+ val &= DSI_VID_VCA_SETTING2_EXACT_BURST_LIMIT_MASK;
+ writel(val, d->regs + DSI_VID_VCA_SETTING2);
+ /*
+ * This BLKEOL duration is claimed to be the duration in clock
+ * cycles of the BLLP end-of-line (EOL) period for each line if
+ * DSI_VID_MAIN_CTL_REG_BLKEOL_MODE_LP_0 is set.
+ *
+ * It is hard to trust the manuals' claim that this is in clock
+ * cycles as we mimic the behaviour of the vendor code, which
+ * appears to write a number of bytes that would have been
+ * transferred on a single lane.
+ *
+ * See the manual figure 657 page 2203 and page 2198 for the 13
+ * reg_blkeol_duration bits.
+ *
+ * FIXME: should this also be set up also for non-burst mode
+ * according to figure 565 page 2202?
+ */
+ blkeol_duration = DIV_ROUND_CLOSEST(blkeol_pck + 6,
+ d->mdsi->lanes);
+ dev_dbg(d->dev, "BLKEOL duration: %d clock cycles\n",
+ blkeol_duration);
+
+ val = readl(d->regs + DSI_VID_PCK_TIME);
+ val &= ~DSI_VID_PCK_TIME_BLKEOL_DURATION_MASK;
+ val |= blkeol_duration <<
+ DSI_VID_PCK_TIME_BLKEOL_DURATION_SHIFT;
+ writel(val, d->regs + DSI_VID_PCK_TIME);
+
+ /* Max burst limit, this is given in bytes */
+ val = readl(d->regs + DSI_VID_VCA_SETTING1);
+ val &= ~DSI_VID_VCA_SETTING1_MAX_BURST_LIMIT_MASK;
+ val |= (blkeol_pck - 6) <<
+ DSI_VID_VCA_SETTING1_MAX_BURST_LIMIT_SHIFT;
+ writel(val, d->regs + DSI_VID_VCA_SETTING1);
}
/* Maximum line limit */
val = readl(d->regs + DSI_VID_VCA_SETTING2);
- val |= blkline_pck <<
- DSI_VID_VCA_SETTING2_EXACT_BURST_LIMIT_SHIFT;
+ val &= ~DSI_VID_VCA_SETTING2_MAX_LINE_LIMIT_MASK;
+ val |= (blkline_pck - 6) <<
+ DSI_VID_VCA_SETTING2_MAX_LINE_LIMIT_SHIFT;
writel(val, d->regs + DSI_VID_VCA_SETTING2);
+ dev_dbg(d->dev, "blkline pck: %d bytes\n", blkline_pck - 6);
/* Put IF1 into video mode */
val = readl(d->regs + DSI_MCTL_MAIN_DATA_CTL);
--- a/drivers/gpu/drm/mcde/mcde_dsi_regs.h
+++ b/drivers/gpu/drm/mcde/mcde_dsi_regs.h
@@ -239,6 +239,7 @@
#define DSI_VID_PCK_TIME 0x000000A8
#define DSI_VID_PCK_TIME_BLKEOL_DURATION_SHIFT 0
+#define DSI_VID_PCK_TIME_BLKEOL_DURATION_MASK 0x00000FFF
#define DSI_VID_DPHY_TIME 0x000000AC
#define DSI_VID_DPHY_TIME_REG_LINE_DURATION_SHIFT 0