linux-yocto/drivers/gpu/drm/xe/xe_gt_topology.c
Lucas De Marchi 7e0fe233aa drm/xe: Fix warning on unreachable statement
eu_type_to_str() relies on -Wswitch to warn (and -Werror) to make sure
it handles all enum values. However it's perfectly legal to pass an int
to that function so in the end that function may happen to return
nothing. There's too much implicit knowledge about the initialization
of eu_type for a compiler  to notice eu_type is never assigned to
anything other than those values.

Trying to reproduce this issue, none of gcc-9, gcc-10 and gcc-13
triggered for me, but this was reported in a different system with
gcc-10:

	drivers/gpu/drm/xe/xe.o: warning: objtool: xe_gt_topology_dump() falls through to next function xe_gt_topology_init()

Also it was reported these warnings when building with clang:

	drivers/gpu/drm/xe/xe.o: warning: objtool: xe_gt_topology_dump+0x77: sibling call from callable instruction with modified stack frame
	drivers/gpu/drm/xe/xe.o: warning: objtool: xe_gt_topology_dump() falls through to next function xe_dss_mask_group_ffs()
	drivers/gpu/drm/xe/xe.o: warning: objtool: xe_gt_topology_dump+0x77: can't find jump dest instruction at .text.xe_gt_topology_dump+0xc0

Since that value is not really possible in real world, just take the
simple approach and return NULL.

Fixes: 7108b4a589 ("drm/xe/uapi: Expose SIMD16 EU mask in topology query")
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240719191534.3845469-1-lucas.demarchi@intel.com
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
2024-07-22 09:43:52 -07:00

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// SPDX-License-Identifier: MIT
/*
* Copyright © 2022 Intel Corporation
*/
#include "xe_gt_topology.h"
#include <linux/bitmap.h>
#include <linux/compiler.h>
#include "regs/xe_gt_regs.h"
#include "xe_assert.h"
#include "xe_gt.h"
#include "xe_mmio.h"
static void
load_dss_mask(struct xe_gt *gt, xe_dss_mask_t mask, int numregs, ...)
{
va_list argp;
u32 fuse_val[XE_MAX_DSS_FUSE_REGS] = {};
int i;
if (drm_WARN_ON(&gt_to_xe(gt)->drm, numregs > XE_MAX_DSS_FUSE_REGS))
numregs = XE_MAX_DSS_FUSE_REGS;
va_start(argp, numregs);
for (i = 0; i < numregs; i++)
fuse_val[i] = xe_mmio_read32(gt, va_arg(argp, struct xe_reg));
va_end(argp);
bitmap_from_arr32(mask, fuse_val, numregs * 32);
}
static void
load_eu_mask(struct xe_gt *gt, xe_eu_mask_t mask, enum xe_gt_eu_type *eu_type)
{
struct xe_device *xe = gt_to_xe(gt);
u32 reg_val = xe_mmio_read32(gt, XELP_EU_ENABLE);
u32 val = 0;
int i;
BUILD_BUG_ON(XE_MAX_EU_FUSE_REGS > 1);
/*
* Pre-Xe_HP platforms inverted the bit meaning (disable instead
* of enable).
*/
if (GRAPHICS_VERx100(xe) < 1250)
reg_val = ~reg_val & XELP_EU_MASK;
if (GRAPHICS_VERx100(xe) == 1260 || GRAPHICS_VER(xe) >= 20) {
/* SIMD16 EUs, one bit == one EU */
*eu_type = XE_GT_EU_TYPE_SIMD16;
val = reg_val;
} else {
/* SIMD8 EUs, one bit == 2 EU */
*eu_type = XE_GT_EU_TYPE_SIMD8;
for (i = 0; i < fls(reg_val); i++)
if (reg_val & BIT(i))
val |= 0x3 << 2 * i;
}
bitmap_from_arr32(mask, &val, XE_MAX_EU_FUSE_BITS);
}
/**
* gen_l3_mask_from_pattern - Replicate a bit pattern according to a mask
*
* It is used to compute the L3 bank masks in a generic format on
* various platforms where the internal representation of L3 node
* and masks from registers are different.
*
* @xe: device
* @dst: destination
* @pattern: pattern to replicate
* @patternbits: size of the pattern, in bits
* @mask: mask describing where to replicate the pattern
*
* Example 1:
* ----------
* @pattern = 0b1111
* └┬─┘
* @patternbits = 4 (bits)
* @mask = 0b0101
* ││││
* │││└────────────────── 0b1111 (=1×0b1111)
* ││└──────────── 0b0000 │ (=0×0b1111)
* │└────── 0b1111 │ │ (=1×0b1111)
* └ 0b0000 │ │ │ (=0×0b1111)
* │ │ │ │
* @dst = 0b0000 0b1111 0b0000 0b1111
*
* Example 2:
* ----------
* @pattern = 0b11111111
* └┬─────┘
* @patternbits = 8 (bits)
* @mask = 0b10
* ││
* ││
* ││
* │└────────── 0b00000000 (=0×0b11111111)
* └ 0b11111111 │ (=1×0b11111111)
* │ │
* @dst = 0b11111111 0b00000000
*/
static void
gen_l3_mask_from_pattern(struct xe_device *xe, xe_l3_bank_mask_t dst,
xe_l3_bank_mask_t pattern, int patternbits,
unsigned long mask)
{
unsigned long bit;
xe_assert(xe, find_last_bit(pattern, XE_MAX_L3_BANK_MASK_BITS) < patternbits ||
bitmap_empty(pattern, XE_MAX_L3_BANK_MASK_BITS));
xe_assert(xe, !mask || patternbits * (__fls(mask) + 1) <= XE_MAX_L3_BANK_MASK_BITS);
for_each_set_bit(bit, &mask, 32) {
xe_l3_bank_mask_t shifted_pattern = {};
bitmap_shift_left(shifted_pattern, pattern, bit * patternbits,
XE_MAX_L3_BANK_MASK_BITS);
bitmap_or(dst, dst, shifted_pattern, XE_MAX_L3_BANK_MASK_BITS);
}
}
static void
load_l3_bank_mask(struct xe_gt *gt, xe_l3_bank_mask_t l3_bank_mask)
{
struct xe_device *xe = gt_to_xe(gt);
u32 fuse3 = xe_mmio_read32(gt, MIRROR_FUSE3);
if (GRAPHICS_VER(xe) >= 20) {
xe_l3_bank_mask_t per_node = {};
u32 meml3_en = REG_FIELD_GET(XE2_NODE_ENABLE_MASK, fuse3);
u32 bank_val = REG_FIELD_GET(XE2_GT_L3_MODE_MASK, fuse3);
bitmap_from_arr32(per_node, &bank_val, 32);
gen_l3_mask_from_pattern(xe, l3_bank_mask, per_node, 4,
meml3_en);
} else if (GRAPHICS_VERx100(xe) >= 1270) {
xe_l3_bank_mask_t per_node = {};
xe_l3_bank_mask_t per_mask_bit = {};
u32 meml3_en = REG_FIELD_GET(MEML3_EN_MASK, fuse3);
u32 fuse4 = xe_mmio_read32(gt, XEHP_FUSE4);
u32 bank_val = REG_FIELD_GET(GT_L3_EXC_MASK, fuse4);
bitmap_set_value8(per_mask_bit, 0x3, 0);
gen_l3_mask_from_pattern(xe, per_node, per_mask_bit, 2, bank_val);
gen_l3_mask_from_pattern(xe, l3_bank_mask, per_node, 4,
meml3_en);
} else if (xe->info.platform == XE_PVC) {
xe_l3_bank_mask_t per_node = {};
xe_l3_bank_mask_t per_mask_bit = {};
u32 meml3_en = REG_FIELD_GET(MEML3_EN_MASK, fuse3);
u32 bank_val = REG_FIELD_GET(XEHPC_GT_L3_MODE_MASK, fuse3);
bitmap_set_value8(per_mask_bit, 0xf, 0);
gen_l3_mask_from_pattern(xe, per_node, per_mask_bit, 4,
bank_val);
gen_l3_mask_from_pattern(xe, l3_bank_mask, per_node, 16,
meml3_en);
} else if (xe->info.platform == XE_DG2) {
xe_l3_bank_mask_t per_node = {};
u32 mask = REG_FIELD_GET(MEML3_EN_MASK, fuse3);
bitmap_set_value8(per_node, 0xff, 0);
gen_l3_mask_from_pattern(xe, l3_bank_mask, per_node, 8, mask);
} else {
/* 1:1 register bit to mask bit (inverted register bits) */
u32 mask = REG_FIELD_GET(XELP_GT_L3_MODE_MASK, ~fuse3);
bitmap_from_arr32(l3_bank_mask, &mask, 32);
}
}
static void
get_num_dss_regs(struct xe_device *xe, int *geometry_regs, int *compute_regs)
{
if (GRAPHICS_VER(xe) > 20) {
*geometry_regs = 3;
*compute_regs = 3;
} else if (GRAPHICS_VERx100(xe) == 1260) {
*geometry_regs = 0;
*compute_regs = 2;
} else if (GRAPHICS_VERx100(xe) >= 1250) {
*geometry_regs = 1;
*compute_regs = 1;
} else {
*geometry_regs = 1;
*compute_regs = 0;
}
}
void
xe_gt_topology_init(struct xe_gt *gt)
{
struct xe_device *xe = gt_to_xe(gt);
struct drm_printer p;
int num_geometry_regs, num_compute_regs;
get_num_dss_regs(xe, &num_geometry_regs, &num_compute_regs);
/*
* Register counts returned shouldn't exceed the number of registers
* passed as parameters below.
*/
drm_WARN_ON(&xe->drm, num_geometry_regs > 3);
drm_WARN_ON(&xe->drm, num_compute_regs > 3);
load_dss_mask(gt, gt->fuse_topo.g_dss_mask,
num_geometry_regs,
XELP_GT_GEOMETRY_DSS_ENABLE,
XE2_GT_GEOMETRY_DSS_1,
XE2_GT_GEOMETRY_DSS_2);
load_dss_mask(gt, gt->fuse_topo.c_dss_mask, num_compute_regs,
XEHP_GT_COMPUTE_DSS_ENABLE,
XEHPC_GT_COMPUTE_DSS_ENABLE_EXT,
XE2_GT_COMPUTE_DSS_2);
load_eu_mask(gt, gt->fuse_topo.eu_mask_per_dss, &gt->fuse_topo.eu_type);
load_l3_bank_mask(gt, gt->fuse_topo.l3_bank_mask);
p = drm_dbg_printer(&gt_to_xe(gt)->drm, DRM_UT_DRIVER, "GT topology");
xe_gt_topology_dump(gt, &p);
}
static const char *eu_type_to_str(enum xe_gt_eu_type eu_type)
{
switch (eu_type) {
case XE_GT_EU_TYPE_SIMD16:
return "simd16";
case XE_GT_EU_TYPE_SIMD8:
return "simd8";
}
return NULL;
}
void
xe_gt_topology_dump(struct xe_gt *gt, struct drm_printer *p)
{
drm_printf(p, "dss mask (geometry): %*pb\n", XE_MAX_DSS_FUSE_BITS,
gt->fuse_topo.g_dss_mask);
drm_printf(p, "dss mask (compute): %*pb\n", XE_MAX_DSS_FUSE_BITS,
gt->fuse_topo.c_dss_mask);
drm_printf(p, "EU mask per DSS: %*pb\n", XE_MAX_EU_FUSE_BITS,
gt->fuse_topo.eu_mask_per_dss);
drm_printf(p, "EU type: %s\n",
eu_type_to_str(gt->fuse_topo.eu_type));
drm_printf(p, "L3 bank mask: %*pb\n", XE_MAX_L3_BANK_MASK_BITS,
gt->fuse_topo.l3_bank_mask);
}
/*
* Used to obtain the index of the first DSS. Can start searching from the
* beginning of a specific dss group (e.g., gslice, cslice, etc.) if
* groupsize and groupnum are non-zero.
*/
unsigned int
xe_dss_mask_group_ffs(const xe_dss_mask_t mask, int groupsize, int groupnum)
{
return find_next_bit(mask, XE_MAX_DSS_FUSE_BITS, groupnum * groupsize);
}
bool xe_dss_mask_empty(const xe_dss_mask_t mask)
{
return bitmap_empty(mask, XE_MAX_DSS_FUSE_BITS);
}
/**
* xe_gt_topology_has_dss_in_quadrant - check fusing of DSS in GT quadrant
* @gt: GT to check
* @quad: Which quadrant of the DSS space to check
*
* Since Xe_HP platforms can have up to four CCS engines, those engines
* are each logically associated with a quarter of the possible DSS. If there
* are no DSS present in one of the four quadrants of the DSS space, the
* corresponding CCS engine is also not available for use.
*
* Returns false if all DSS in a quadrant of the GT are fused off, else true.
*/
bool xe_gt_topology_has_dss_in_quadrant(struct xe_gt *gt, int quad)
{
struct xe_device *xe = gt_to_xe(gt);
xe_dss_mask_t all_dss;
int g_dss_regs, c_dss_regs, dss_per_quad, quad_first;
bitmap_or(all_dss, gt->fuse_topo.g_dss_mask, gt->fuse_topo.c_dss_mask,
XE_MAX_DSS_FUSE_BITS);
get_num_dss_regs(xe, &g_dss_regs, &c_dss_regs);
dss_per_quad = 32 * max(g_dss_regs, c_dss_regs) / 4;
quad_first = xe_dss_mask_group_ffs(all_dss, dss_per_quad, quad);
return quad_first < (quad + 1) * dss_per_quad;
}
bool xe_gt_has_geometry_dss(struct xe_gt *gt, unsigned int dss)
{
return test_bit(dss, gt->fuse_topo.g_dss_mask);
}
bool xe_gt_has_compute_dss(struct xe_gt *gt, unsigned int dss)
{
return test_bit(dss, gt->fuse_topo.c_dss_mask);
}