[PATCH 02/28] drm/amd/display: Rework dsc to isolate FPU operations
Qingqing Zhuo
qingqing.zhuo at amd.com
Mon Jun 8 04:59:00 UTC 2020
From: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
When we want to use float point operation on Linux
we need to use within special kernel protection
(`kernel_fpu_{begin,end}()`.), otherwise the kernel
can clobber userspace FPU register state. For detecting
these issues we use a tool named objtool (with -Ffa
flags) to highlight the FPU problems, all warnings can
be summed up as follows:
./tools/objtool/objtool check -Ffa
drivers/gpu/drm/amd/display/dc/dml/dml_common_defs.o
[..] dc/dsc/rc_calc.o: warning: objtool: get_qp_set()+0x2f8:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc.o: warning: objtool: dsc_roundf()+0x5:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc.o: warning: objtool: dsc_ceil()+0x5:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc.o: warning: objtool: get_ofs_set()+0x3eb:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc.o: warning: objtool: calc_rc_params()+0x3c:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/dc_dsc.o: warning: objtool:
get_dsc_bandwidth_range.isra.0()+0x8d:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/dc_dsc.o: warning: objtool: setup_dsc_config()+0x2ef:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc_dpi.o: warning: objtool:copy_pps_fields()+0xbb:
FPU instruction outside of kernel_fpu_{begin,end}()
[..] dc/dsc/rc_calc_dpi.o: warning: objtool:
dscc_compute_dsc_parameters()+0x7b:
FPU instruction outside of kernel_fpu_{begin,end}()
This commit fixes the above issues by rework DSC as described:
1. Isolate all FPU operations in a single file;
2. Use FPU flags only in the file that handles FPU operations;
3. Isolate all functions that require float point operation in static
functions;
4. Add a mid-layer function that does not use any float point operation,
and that could be safely invoked in other parts of the code.
5. Keep float point operation under DC_FP_{START/END} macro.
CC: Christian König <christian.koenig at amd.com>
CC: Alexander Deucher <Alexander.Deucher at amd.com>
CC: Peter Zijlstra <peterz at infradead.org>
CC: Tony Cheng <tony.cheng at amd.com>
CC: Harry Wentland <hwentlan at amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira at amd.com>
Reviewed-by: Mikita Lipski <Mikita.Lipski at amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo at amd.com>
---
drivers/gpu/drm/amd/display/dc/dsc/Makefile | 2 -
drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c | 18 +--
drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c | 151 +++++++++++++++++-
drivers/gpu/drm/amd/display/dc/dsc/rc_calc.h | 5 +-
.../gpu/drm/amd/display/dc/dsc/rc_calc_dpi.c | 27 +---
5 files changed, 153 insertions(+), 50 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dsc/Makefile b/drivers/gpu/drm/amd/display/dc/dsc/Makefile
index 3f66868df171..ea29cf95d470 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/dsc/Makefile
@@ -28,8 +28,6 @@ endif
endif
CFLAGS_$(AMDDALPATH)/dc/dsc/rc_calc.o := $(dsc_ccflags)
-CFLAGS_$(AMDDALPATH)/dc/dsc/rc_calc_dpi.o := $(dsc_ccflags)
-CFLAGS_$(AMDDALPATH)/dc/dsc/dc_dsc.o := $(dsc_ccflags)
DSC = dc_dsc.o rc_calc.o rc_calc_dpi.o
diff --git a/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c b/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
index 0ea6662a1563..0c7f247bb7de 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
+++ b/drivers/gpu/drm/amd/display/dc/dsc/dc_dsc.c
@@ -22,10 +22,12 @@
* Author: AMD
*/
+#include <drm/drm_dsc.h>
#include "dc_hw_types.h"
#include "dsc.h"
#include <drm/drm_dp_helper.h>
#include "dc.h"
+#include "rc_calc.h"
/* This module's internal functions */
@@ -304,22 +306,6 @@ static inline uint32_t dsc_div_by_10_round_up(uint32_t value)
return (value + 9) / 10;
}
-static inline uint32_t calc_dsc_bpp_x16(uint32_t stream_bandwidth_kbps, uint32_t pix_clk_100hz, uint32_t bpp_increment_div)
-{
- uint32_t dsc_target_bpp_x16;
- float f_dsc_target_bpp;
- float f_stream_bandwidth_100bps = stream_bandwidth_kbps * 10.0f;
- uint32_t precision = bpp_increment_div; // bpp_increment_div is actually precision
-
- f_dsc_target_bpp = f_stream_bandwidth_100bps / pix_clk_100hz;
-
- // Round down to the nearest precision stop to bring it into DSC spec range
- dsc_target_bpp_x16 = (uint32_t)(f_dsc_target_bpp * precision);
- dsc_target_bpp_x16 = (dsc_target_bpp_x16 * 16) / precision;
-
- return dsc_target_bpp_x16;
-}
-
/* Get DSC bandwidth range based on [min_bpp, max_bpp] target bitrate range, and timing's pixel clock
* and uncompressed bandwidth.
*/
diff --git a/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c b/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c
index 03ae15946c6d..667afbc260f9 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c
+++ b/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.c
@@ -23,6 +23,7 @@
* Authors: AMD
*
*/
+#include <drm/drm_dsc.h>
#include "os_types.h"
#include "rc_calc.h"
@@ -40,7 +41,8 @@
break
-void get_qp_set(qp_set qps, enum colour_mode cm, enum bits_per_comp bpc, enum max_min max_min, float bpp)
+static void get_qp_set(qp_set qps, enum colour_mode cm, enum bits_per_comp bpc,
+ enum max_min max_min, float bpp)
{
int mode = MODE_SELECT(444, 422, 420);
int sel = table_hash(mode, bpc, max_min);
@@ -85,7 +87,7 @@ void get_qp_set(qp_set qps, enum colour_mode cm, enum bits_per_comp bpc, enum ma
memcpy(qps, table[index].qps, sizeof(qp_set));
}
-double dsc_roundf(double num)
+static double dsc_roundf(double num)
{
if (num < 0.0)
num = num - 0.5;
@@ -95,7 +97,7 @@ double dsc_roundf(double num)
return (int)(num);
}
-double dsc_ceil(double num)
+static double dsc_ceil(double num)
{
double retval = (int)num;
@@ -105,7 +107,7 @@ double dsc_ceil(double num)
return (int)retval;
}
-void get_ofs_set(qp_set ofs, enum colour_mode mode, float bpp)
+static void get_ofs_set(qp_set ofs, enum colour_mode mode, float bpp)
{
int *p = ofs;
@@ -160,7 +162,7 @@ void get_ofs_set(qp_set ofs, enum colour_mode mode, float bpp)
}
}
-int median3(int a, int b, int c)
+static int median3(int a, int b, int c)
{
if (a > b)
swap(a, b);
@@ -172,13 +174,25 @@ int median3(int a, int b, int c)
return b;
}
-void calc_rc_params(struct rc_params *rc, enum colour_mode cm, enum bits_per_comp bpc, float bpp, int slice_width, int slice_height, int minor_version)
+static void _do_calc_rc_params(struct rc_params *rc, enum colour_mode cm,
+ enum bits_per_comp bpc, u8 drm_bpp,
+ bool is_navite_422_or_420,
+ int slice_width, int slice_height,
+ int minor_version)
{
+ float bpp;
float bpp_group;
float initial_xmit_delay_factor;
int padding_pixels;
int i;
+ bpp = ((float)drm_bpp / 16.0);
+ /* in native_422 or native_420 modes, the bits_per_pixel is double the
+ * target bpp (the latter is what calc_rc_params expects)
+ */
+ if (is_navite_422_or_420)
+ bpp /= 2.0;
+
rc->rc_quant_incr_limit0 = ((bpc == BPC_8) ? 11 : (bpc == BPC_10 ? 15 : 19)) - ((minor_version == 1 && cm == CM_444) ? 1 : 0);
rc->rc_quant_incr_limit1 = ((bpc == BPC_8) ? 11 : (bpc == BPC_10 ? 15 : 19)) - ((minor_version == 1 && cm == CM_444) ? 1 : 0);
@@ -251,3 +265,128 @@ void calc_rc_params(struct rc_params *rc, enum colour_mode cm, enum bits_per_com
rc->rc_buf_thresh[13] = 8064;
}
+static u32 _do_bytes_per_pixel_calc(int slice_width, u8 drm_bpp,
+ bool is_navite_422_or_420)
+{
+ float bpp;
+ u32 bytes_per_pixel;
+ double d_bytes_per_pixel;
+
+ bpp = ((float)drm_bpp / 16.0);
+ d_bytes_per_pixel = dsc_ceil(bpp * slice_width / 8.0) / slice_width;
+ // TODO: Make sure the formula for calculating this is precise (ceiling
+ // vs. floor, and at what point they should be applied)
+ if (is_navite_422_or_420)
+ d_bytes_per_pixel /= 2;
+
+ bytes_per_pixel = (u32)dsc_ceil(d_bytes_per_pixel * 0x10000000);
+
+ return bytes_per_pixel;
+}
+
+static u32 _do_calc_dsc_bpp_x16(u32 stream_bandwidth_kbps, u32 pix_clk_100hz,
+ u32 bpp_increment_div)
+{
+ u32 dsc_target_bpp_x16;
+ float f_dsc_target_bpp;
+ float f_stream_bandwidth_100bps;
+ // bpp_increment_div is actually precision
+ u32 precision = bpp_increment_div;
+
+ f_stream_bandwidth_100bps = stream_bandwidth_kbps * 10.0f;
+ f_dsc_target_bpp = f_stream_bandwidth_100bps / pix_clk_100hz;
+
+ // Round down to the nearest precision stop to bring it into DSC spec
+ // range
+ dsc_target_bpp_x16 = (u32)(f_dsc_target_bpp * precision);
+ dsc_target_bpp_x16 = (dsc_target_bpp_x16 * 16) / precision;
+
+ return dsc_target_bpp_x16;
+}
+
+/**
+ * calc_rc_params - reads the user's cmdline mode
+ * @rc: DC internal DSC parameters
+ * @pps: DRM struct with all required DSC values
+ *
+ * This function expects a drm_dsc_config data struct with all the required DSC
+ * values previously filled out by our driver and based on this information it
+ * computes some of the DSC values.
+ *
+ * @note This calculation requires float point operation, most of it executes
+ * under kernel_fpu_{begin,end}.
+ */
+void calc_rc_params(struct rc_params *rc, const struct drm_dsc_config *pps)
+{
+ enum colour_mode mode;
+ enum bits_per_comp bpc;
+ bool is_navite_422_or_420;
+ u8 drm_bpp = pps->bits_per_pixel;
+ int slice_width = pps->slice_width;
+ int slice_height = pps->slice_height;
+
+ mode = pps->convert_rgb ? CM_RGB : (pps->simple_422 ? CM_444 :
+ (pps->native_422 ? CM_422 :
+ pps->native_420 ? CM_420 : CM_444));
+ bpc = (pps->bits_per_component == 8) ? BPC_8 : (pps->bits_per_component == 10)
+ ? BPC_10 : BPC_12;
+
+ is_navite_422_or_420 = pps->native_422 || pps->native_420;
+
+ DC_FP_START();
+ _do_calc_rc_params(rc, mode, bpc, drm_bpp, is_navite_422_or_420,
+ slice_width, slice_height,
+ pps->dsc_version_minor);
+ DC_FP_END();
+}
+
+/**
+ * calc_dsc_bytes_per_pixel - calculate bytes per pixel
+ * @pps: DRM struct with all required DSC values
+ *
+ * Based on the information inside drm_dsc_config, this function calculates the
+ * total of bytes per pixel.
+ *
+ * @note This calculation requires float point operation, most of it executes
+ * under kernel_fpu_{begin,end}.
+ *
+ * Return:
+ * Return the number of bytes per pixel
+ */
+u32 calc_dsc_bytes_per_pixel(const struct drm_dsc_config *pps)
+
+{
+ u32 ret;
+ u8 drm_bpp = pps->bits_per_pixel;
+ int slice_width = pps->slice_width;
+ bool is_navite_422_or_420 = pps->native_422 || pps->native_420;
+
+ DC_FP_START();
+ ret = _do_bytes_per_pixel_calc(slice_width, drm_bpp,
+ is_navite_422_or_420);
+ DC_FP_END();
+ return ret;
+}
+
+/**
+ * calc_dsc_bpp_x16 - retrieve the dsc bits per pixel
+ * @stream_bandwidth_kbps:
+ * @pix_clk_100hz:
+ * @bpp_increment_div:
+ *
+ * Calculate the total of bits per pixel for DSC configuration.
+ *
+ * @note This calculation requires float point operation, most of it executes
+ * under kernel_fpu_{begin,end}.
+ */
+u32 calc_dsc_bpp_x16(u32 stream_bandwidth_kbps, u32 pix_clk_100hz,
+ u32 bpp_increment_div)
+{
+ u32 dsc_bpp;
+
+ DC_FP_START();
+ dsc_bpp = _do_calc_dsc_bpp_x16(stream_bandwidth_kbps, pix_clk_100hz,
+ bpp_increment_div);
+ DC_FP_END();
+ return dsc_bpp;
+}
diff --git a/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.h b/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.h
index b6b1f09c2009..21723fa6561e 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.h
+++ b/drivers/gpu/drm/amd/display/dc/dsc/rc_calc.h
@@ -77,7 +77,10 @@ struct qp_entry {
typedef struct qp_entry qp_table[];
-void calc_rc_params(struct rc_params *rc, enum colour_mode cm, enum bits_per_comp bpc, float bpp, int slice_width, int slice_height, int minor_version);
+void calc_rc_params(struct rc_params *rc, const struct drm_dsc_config *pps);
+u32 calc_dsc_bytes_per_pixel(const struct drm_dsc_config *pps);
+u32 calc_dsc_bpp_x16(u32 stream_bandwidth_kbps, u32 pix_clk_100hz,
+ u32 bpp_increment_div);
#endif
diff --git a/drivers/gpu/drm/amd/display/dc/dsc/rc_calc_dpi.c b/drivers/gpu/drm/amd/display/dc/dsc/rc_calc_dpi.c
index 1f6e63b71456..ef830aded5b1 100644
--- a/drivers/gpu/drm/amd/display/dc/dsc/rc_calc_dpi.c
+++ b/drivers/gpu/drm/amd/display/dc/dsc/rc_calc_dpi.c
@@ -27,8 +27,6 @@
#include "dscc_types.h"
#include "rc_calc.h"
-double dsc_ceil(double num);
-
static void copy_pps_fields(struct drm_dsc_config *to, const struct drm_dsc_config *from)
{
to->line_buf_depth = from->line_buf_depth;
@@ -100,34 +98,13 @@ static void copy_rc_to_cfg(struct drm_dsc_config *dsc_cfg, const struct rc_param
int dscc_compute_dsc_parameters(const struct drm_dsc_config *pps, struct dsc_parameters *dsc_params)
{
- enum colour_mode mode = pps->convert_rgb ? CM_RGB :
- (pps->simple_422 ? CM_444 :
- (pps->native_422 ? CM_422 :
- pps->native_420 ? CM_420 : CM_444));
- enum bits_per_comp bpc = (pps->bits_per_component == 8) ? BPC_8 :
- (pps->bits_per_component == 10) ? BPC_10 : BPC_12;
- float bpp = ((float) pps->bits_per_pixel / 16.0);
- int slice_width = pps->slice_width;
- int slice_height = pps->slice_height;
int ret;
struct rc_params rc;
struct drm_dsc_config dsc_cfg;
- double d_bytes_per_pixel = dsc_ceil(bpp * slice_width / 8.0) / slice_width;
-
- // TODO: Make sure the formula for calculating this is precise (ceiling vs. floor, and at what point they should be applied)
- if (pps->native_422 || pps->native_420)
- d_bytes_per_pixel /= 2;
-
- dsc_params->bytes_per_pixel = (uint32_t)dsc_ceil(d_bytes_per_pixel * 0x10000000);
-
- /* in native_422 or native_420 modes, the bits_per_pixel is double the target bpp
- * (the latter is what calc_rc_params expects)
- */
- if (pps->native_422 || pps->native_420)
- bpp /= 2.0;
+ dsc_params->bytes_per_pixel = calc_dsc_bytes_per_pixel(pps);
- calc_rc_params(&rc, mode, bpc, bpp, slice_width, slice_height, pps->dsc_version_minor);
+ calc_rc_params(&rc, pps);
dsc_params->pps = *pps;
dsc_params->pps.initial_scale_value = 8 * rc.rc_model_size / (rc.rc_model_size - rc.initial_fullness_offset);
--
2.17.1
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