Commit d9218c8f authored by Manasi Navare's avatar Manasi Navare
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drm/i915/dp: Add helpers for Compressed BPP and Slice Count for DSC



This patch adds helpers for calculating the maximum compressed BPP
supported with small joiner.
This also adds a helper for calculating the slice count in case
of small joiner.
These are inside intel_dp since they take into account hardware
limitations.

v6:
* Take mode_clock and mode_hdisplay as input arguments
so that this can be called in intel_dp_mode_valid (Manasi)
v5:
* Get the max slice width from DPCD
* Check against Min_Slice_width of 2560 (Anusha)
v4:
* #defines for PPR in slice count helper (Gaurav)
v3:
* Simply logic for bpp (DK)
* Limit the valid slice count by max supported by Sink (Manasi)
v2:
* Change the small joiner RAM buffer constant as bspec changed (Manasi)
* rename it as SMALL_JOINER since we are not enabling
big joiner yet (Anusha)

Cc: Gaurav K Singh <gaurav.k.singh@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: default avatarManasi Navare <manasi.d.navare@intel.com>
Reviewed-by: default avatarAnusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: default avatarGaurav K Singh <gaurav.k.singh@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181031001923.31442-5-manasi.d.navare@intel.com
parent 05756500
......@@ -45,6 +45,17 @@
#define DP_DPRX_ESI_LEN 14
/* DP DSC small joiner has 2 FIFOs each of 640 x 6 bytes */
#define DP_DSC_MAX_SMALL_JOINER_RAM_BUFFER 61440
/* DP DSC throughput values used for slice count calculations KPixels/s */
#define DP_DSC_PEAK_PIXEL_RATE 2720000
#define DP_DSC_MAX_ENC_THROUGHPUT_0 340000
#define DP_DSC_MAX_ENC_THROUGHPUT_1 400000
/* DP DSC FEC Overhead factor = (100 - 2.4)/100 */
#define DP_DSC_FEC_OVERHEAD_FACTOR 976
/* Compliance test status bits */
#define INTEL_DP_RESOLUTION_SHIFT_MASK 0
#define INTEL_DP_RESOLUTION_PREFERRED (1 << INTEL_DP_RESOLUTION_SHIFT_MASK)
......@@ -93,6 +104,14 @@ static const struct dp_link_dpll chv_dpll[] = {
{ .p1 = 4, .p2 = 1, .n = 1, .m1 = 2, .m2 = 0x6c00000 } },
};
/* Constants for DP DSC configurations */
static const u8 valid_dsc_bpp[] = {6, 8, 10, 12, 15};
/* With Single pipe configuration, HW is capable of supporting maximum
* of 4 slices per line.
*/
static const u8 valid_dsc_slicecount[] = {1, 2, 4};
/**
* intel_dp_is_edp - is the given port attached to an eDP panel (either CPU or PCH)
* @intel_dp: DP struct
......@@ -4162,6 +4181,91 @@ intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *sink_irq_vector)
DP_DPRX_ESI_LEN;
}
u16 intel_dp_dsc_get_output_bpp(int link_clock, uint8_t lane_count,
int mode_clock, int mode_hdisplay)
{
u16 bits_per_pixel, max_bpp_small_joiner_ram;
int i;
/*
* Available Link Bandwidth(Kbits/sec) = (NumberOfLanes)*
* (LinkSymbolClock)* 8 * ((100-FECOverhead)/100)*(TimeSlotsPerMTP)
* FECOverhead = 2.4%, for SST -> TimeSlotsPerMTP is 1,
* for MST -> TimeSlotsPerMTP has to be calculated
*/
bits_per_pixel = (link_clock * lane_count * 8 *
DP_DSC_FEC_OVERHEAD_FACTOR) /
mode_clock;
/* Small Joiner Check: output bpp <= joiner RAM (bits) / Horiz. width */
max_bpp_small_joiner_ram = DP_DSC_MAX_SMALL_JOINER_RAM_BUFFER /
mode_hdisplay;
/*
* Greatest allowed DSC BPP = MIN (output BPP from avaialble Link BW
* check, output bpp from small joiner RAM check)
*/
bits_per_pixel = min(bits_per_pixel, max_bpp_small_joiner_ram);
/* Error out if the max bpp is less than smallest allowed valid bpp */
if (bits_per_pixel < valid_dsc_bpp[0]) {
DRM_DEBUG_KMS("Unsupported BPP %d\n", bits_per_pixel);
return 0;
}
/* Find the nearest match in the array of known BPPs from VESA */
for (i = 0; i < ARRAY_SIZE(valid_dsc_bpp) - 1; i++) {
if (bits_per_pixel < valid_dsc_bpp[i + 1])
break;
}
bits_per_pixel = valid_dsc_bpp[i];
/*
* Compressed BPP in U6.4 format so multiply by 16, for Gen 11,
* fractional part is 0
*/
return bits_per_pixel << 4;
}
u8 intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp,
int mode_clock,
int mode_hdisplay)
{
u8 min_slice_count, i;
int max_slice_width;
if (mode_clock <= DP_DSC_PEAK_PIXEL_RATE)
min_slice_count = DIV_ROUND_UP(mode_clock,
DP_DSC_MAX_ENC_THROUGHPUT_0);
else
min_slice_count = DIV_ROUND_UP(mode_clock,
DP_DSC_MAX_ENC_THROUGHPUT_1);
max_slice_width = drm_dp_dsc_sink_max_slice_width(intel_dp->dsc_dpcd);
if (max_slice_width < DP_DSC_MIN_SLICE_WIDTH_VALUE) {
DRM_DEBUG_KMS("Unsupported slice width %d by DP DSC Sink device\n",
max_slice_width);
return 0;
}
/* Also take into account max slice width */
min_slice_count = min_t(uint8_t, min_slice_count,
DIV_ROUND_UP(mode_hdisplay,
max_slice_width));
/* Find the closest match to the valid slice count values */
for (i = 0; i < ARRAY_SIZE(valid_dsc_slicecount); i++) {
if (valid_dsc_slicecount[i] >
drm_dp_dsc_sink_max_slice_count(intel_dp->dsc_dpcd,
false))
break;
if (min_slice_count <= valid_dsc_slicecount[i])
return valid_dsc_slicecount[i];
}
DRM_DEBUG_KMS("Unsupported Slice Count %d\n", min_slice_count);
return 0;
}
static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
{
int status = 0;
......
......@@ -1836,6 +1836,10 @@ bool intel_dp_source_supports_hbr2(struct intel_dp *intel_dp);
bool intel_dp_source_supports_hbr3(struct intel_dp *intel_dp);
bool
intel_dp_get_link_status(struct intel_dp *intel_dp, uint8_t link_status[DP_LINK_STATUS_SIZE]);
uint16_t intel_dp_dsc_get_output_bpp(int link_clock, uint8_t lane_count,
int mode_clock, int mode_hdisplay);
uint8_t intel_dp_dsc_get_slice_count(struct intel_dp *intel_dp, int mode_clock,
int mode_hdisplay);
static inline unsigned int intel_dp_unused_lane_mask(int lane_count)
{
......
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