drivers/gpu/drm/amd/amdgpu/dce_v6_0.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/amd/amdgpu/dce_v6_0.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/amd/amdgpu/dce_v6_0.c
Extension
.c
Size
112173 bytes
Lines
3565
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct dce6_wm_params {
	u32 dram_channels; /* number of dram channels */
	u32 yclk;          /* bandwidth per dram data pin in kHz */
	u32 sclk;          /* engine clock in kHz */
	u32 disp_clk;      /* display clock in kHz */
	u32 src_width;     /* viewport width */
	u32 active_time;   /* active display time in ns */
	u32 blank_time;    /* blank time in ns */
	bool interlaced;    /* mode is interlaced */
	fixed20_12 vsc;    /* vertical scale ratio */
	u32 num_heads;     /* number of active crtcs */
	u32 bytes_per_pixel; /* bytes per pixel display + overlay */
	u32 lb_size;       /* line buffer allocated to pipe */
	u32 vtaps;         /* vertical scaler taps */
};

/**
 * dce_v6_0_dram_bandwidth - get the dram bandwidth
 *
 * @wm: watermark calculation data
 *
 * Calculate the raw dram bandwidth (CIK).
 * Used for display watermark bandwidth calculations
 * Returns the dram bandwidth in MBytes/s
 */
static u32 dce_v6_0_dram_bandwidth(struct dce6_wm_params *wm)
{
	/* Calculate raw DRAM Bandwidth */
	fixed20_12 dram_efficiency; /* 0.7 */
	fixed20_12 yclk, dram_channels, bandwidth;
	fixed20_12 a;

	a.full = dfixed_const(1000);
	yclk.full = dfixed_const(wm->yclk);
	yclk.full = dfixed_div(yclk, a);
	dram_channels.full = dfixed_const(wm->dram_channels * 4);
	a.full = dfixed_const(10);
	dram_efficiency.full = dfixed_const(7);
	dram_efficiency.full = dfixed_div(dram_efficiency, a);
	bandwidth.full = dfixed_mul(dram_channels, yclk);
	bandwidth.full = dfixed_mul(bandwidth, dram_efficiency);

	return dfixed_trunc(bandwidth);
}

/**
 * dce_v6_0_dram_bandwidth_for_display - get the dram bandwidth for display
 *
 * @wm: watermark calculation data
 *
 * Calculate the dram bandwidth used for display (CIK).
 * Used for display watermark bandwidth calculations
 * Returns the dram bandwidth for display in MBytes/s
 */
static u32 dce_v6_0_dram_bandwidth_for_display(struct dce6_wm_params *wm)
{
	/* Calculate DRAM Bandwidth and the part allocated to display. */
	fixed20_12 disp_dram_allocation; /* 0.3 to 0.7 */
	fixed20_12 yclk, dram_channels, bandwidth;
	fixed20_12 a;

	a.full = dfixed_const(1000);
	yclk.full = dfixed_const(wm->yclk);
	yclk.full = dfixed_div(yclk, a);
	dram_channels.full = dfixed_const(wm->dram_channels * 4);
	a.full = dfixed_const(10);
	disp_dram_allocation.full = dfixed_const(3); /* XXX worse case value 0.3 */
	disp_dram_allocation.full = dfixed_div(disp_dram_allocation, a);
	bandwidth.full = dfixed_mul(dram_channels, yclk);
	bandwidth.full = dfixed_mul(bandwidth, disp_dram_allocation);

	return dfixed_trunc(bandwidth);
}

/**
 * dce_v6_0_data_return_bandwidth - get the data return bandwidth
 *
 * @wm: watermark calculation data
 *
 * Calculate the data return bandwidth used for display (CIK).
 * Used for display watermark bandwidth calculations
 * Returns the data return bandwidth in MBytes/s
 */
static u32 dce_v6_0_data_return_bandwidth(struct dce6_wm_params *wm)
{
	/* Calculate the display Data return Bandwidth */
	fixed20_12 return_efficiency; /* 0.8 */
	fixed20_12 sclk, bandwidth;
	fixed20_12 a;

Annotation

Implementation Notes