Re: [Intel-gfx] [PATCH v4 01/18] drm/i915/xehp: handle new steering options

Lucas De Marchi
2021-08-04T19:53:40Z

On Thu, Jul 29, 2021 at 09:59:51AM -0700, Matt Roper wrote:
>From: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
>
>Xe_HP is more modular than its predecessors and as a consequence it has
>more types of replicated registers. As with l3bank regions on previous
>platforms, we may need to explicitly re-steer accesses to these new
>types of ranges at runtime if we can't find a single default steering
>value that satisfies the fusing of all types.
>
>v2:
> - Add a local 'i915' variable to reduce gt->i915 usage. (Caz)
> - Drop unused 'intel_gt_read_register' prototype. (Caz)
>
>Bspec: 66534
>Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
>Cc: Caz Yokoyama <caz.yokoyama@intel.com>
>Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
>Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
>---
> drivers/gpu/drm/i915/gt/intel_gt.c | 42 +++++++++-
> drivers/gpu/drm/i915/gt/intel_gt_types.h | 7 ++
> drivers/gpu/drm/i915/gt/intel_region_lmem.c | 1 +
> drivers/gpu/drm/i915/gt/intel_sseu.c | 18 +++++
> drivers/gpu/drm/i915/gt/intel_sseu.h | 6 ++
> drivers/gpu/drm/i915/gt/intel_workarounds.c | 89 +++++++++++++++++++--
> drivers/gpu/drm/i915/i915_drv.h | 3 +
> drivers/gpu/drm/i915/i915_pci.c | 1 +
> drivers/gpu/drm/i915/i915_reg.h | 4 +
> drivers/gpu/drm/i915/intel_device_info.h | 1 +
> 10 files changed, 166 insertions(+), 6 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
>index a64aa43f7cd9..39b224600f38 100644
>--- a/drivers/gpu/drm/i915/gt/intel_gt.c
>+++ b/drivers/gpu/drm/i915/gt/intel_gt.c
>@@ -89,18 +89,40 @@ static const struct intel_mmio_range icl_l3bank_steering_table[] = {
> {},
> };
>
>+static u16 slicemask(struct intel_gt *gt, int count)
>+{
>+ u64 dss_mask = intel_sseu_get_subslices(&gt->info.sseu, 0);
>+
>+ return intel_slicemask_from_dssmask(dss_mask, count);
>+}
>+
> int intel_gt_init_mmio(struct intel_gt *gt)
> {
>+ struct drm_i915_private *i915 = gt->i915;
>+
> intel_gt_init_clock_frequency(gt);
>
> intel_uc_init_mmio(&gt->uc);
> intel_sseu_info_init(gt);
>
>- if (GRAPHICS_VER(gt->i915) >= 11) {
>+ /*
>+ * An mslice is unavailable only if both the meml3 for the slice is
>+ * disabled *and* all of the DSS in the slice (quadrant) are disabled.
>+ */
>+ if (HAS_MSLICES(i915))
>+ gt->info.mslice_mask =
>+ slicemask(gt, GEN_DSS_PER_MSLICE) |
>+ (intel_uncore_read(gt->uncore, GEN10_MIRROR_FUSE3) &
>+ GEN12_MEML3_EN_MASK);
>+
>+ if (GRAPHICS_VER(i915) >= 11 &&
>+ GRAPHICS_VER_FULL(i915) < IP_VER(12, 50)) {
> gt->steering_table[L3BANK] = icl_l3bank_steering_table;
> gt->info.l3bank_mask =
> ~intel_uncore_read(gt->uncore, GEN10_MIRROR_FUSE3) &
> GEN10_L3BANK_MASK;
>+ } else if (HAS_MSLICES(i915)) {
>+ MISSING_CASE(INTEL_INFO(i915)->platform);
> }
>
> return intel_engines_init_mmio(gt);
>@@ -787,6 +809,24 @@ static void intel_gt_get_valid_steering(struct intel_gt *gt,
> *sliceid = 0; /* unused */
> *subsliceid = __ffs(gt->info.l3bank_mask);
> break;
>+ case MSLICE:
>+ GEM_DEBUG_WARN_ON(!gt->info.mslice_mask); /* should be impossible! */
>+
>+ *sliceid = __ffs(gt->info.mslice_mask);
>+ *subsliceid = 0; /* unused */
>+ break;
>+ case LNCF:
>+ GEM_DEBUG_WARN_ON(!gt->info.mslice_mask); /* should be impossible! */
>+
>+ /*
>+ * 0xFDC[29:28] selects the mslice to steer to and 0xFDC[27]

not sure if this clarifies, since this wording does not come from
bspec... bspec rather says (0, 1) -> LNCFS in MSLICE0, (2, 3) -> LNCFS
in MSLICE1, etc. Yes, they are equivalent, but I'd be ok with just the
second part (below) of this comment.... Unless we have this wording
somewhere in bspec I'm not seeing.

>+ * selects which LNCF within the mslice to steer to. An LNCF
>+ * is always present if its mslice is present, so we can safely
>+ * just steer to LNCF 0 in all cases.
>+ */
>+ *sliceid = __ffs(gt->info.mslice_mask) << 1;
>+ *subsliceid = 0; /* unused */
>+ break;
> default:
> MISSING_CASE(type);
> *sliceid = 0;
>diff --git a/drivers/gpu/drm/i915/gt/intel_gt_types.h b/drivers/gpu/drm/i915/gt/intel_gt_types.h
>index 97a5075288d2..a81e21bf1bd1 100644
>--- a/drivers/gpu/drm/i915/gt/intel_gt_types.h
>+++ b/drivers/gpu/drm/i915/gt/intel_gt_types.h
>@@ -47,9 +47,14 @@ struct intel_mmio_range {
> * of multicast registers. If another type of steering does not have any
> * overlap in valid steering targets with 'subslice' style registers, we will
> * need to explicitly re-steer reads of registers of the other type.
>+ *
>+ * Only the replication types that may need additional non-default steering
>+ * are listed here.
> */
> enum intel_steering_type {
> L3BANK,
>+ MSLICE,
>+ LNCF,
>
> NUM_STEERING_TYPES
> };
>@@ -184,6 +189,8 @@ struct intel_gt {
>
> /* Slice/subslice/EU info */
> struct sseu_dev_info sseu;
>+
>+ unsigned long mslice_mask;
> } info;
> };
>
>diff --git a/drivers/gpu/drm/i915/gt/intel_region_lmem.c b/drivers/gpu/drm/i915/gt/intel_region_lmem.c
>index e3a2a2fa5f94..a74b72f50cc9 100644
>--- a/drivers/gpu/drm/i915/gt/intel_region_lmem.c
>+++ b/drivers/gpu/drm/i915/gt/intel_region_lmem.c
>@@ -10,6 +10,7 @@
> #include "gem/i915_gem_lmem.h"
> #include "gem/i915_gem_region.h"
> #include "gem/i915_gem_ttm.h"
>+#include "gt/intel_gt.h"
>
> static int init_fake_lmem_bar(struct intel_memory_region *mem)
> {
>diff --git a/drivers/gpu/drm/i915/gt/intel_sseu.c b/drivers/gpu/drm/i915/gt/intel_sseu.c
>index 367fd44b81c8..bbed8e8625e1 100644
>--- a/drivers/gpu/drm/i915/gt/intel_sseu.c
>+++ b/drivers/gpu/drm/i915/gt/intel_sseu.c
>@@ -759,3 +759,21 @@ void intel_sseu_print_topology(const struct sseu_dev_info *sseu,
> }
> }
> }
>+
>+u16 intel_slicemask_from_dssmask(u64 dss_mask, int dss_per_slice)
>+{
>+ u16 slice_mask = 0;
>+ int i;
>+
>+ WARN_ON(sizeof(dss_mask) * 8 / dss_per_slice > 8 * sizeof(slice_mask));
>+
>+ for (i = 0; dss_mask; i++) {
>+ if (dss_mask & GENMASK(dss_per_slice - 1, 0))
>+ slice_mask |= BIT(i);
>+
>+ dss_mask >>= dss_per_slice;
>+ }
>+
>+ return slice_mask;
>+}
>+
>diff --git a/drivers/gpu/drm/i915/gt/intel_sseu.h b/drivers/gpu/drm/i915/gt/intel_sseu.h
>index 4cd1a8a7298a..1073471d1980 100644
>--- a/drivers/gpu/drm/i915/gt/intel_sseu.h
>+++ b/drivers/gpu/drm/i915/gt/intel_sseu.h
>@@ -22,6 +22,10 @@ struct drm_printer;
> #define GEN_MAX_EUS (16) /* TGL upper bound */
> #define GEN_MAX_EU_STRIDE GEN_SSEU_STRIDE(GEN_MAX_EUS)
>
>+#define GEN_DSS_PER_GSLICE 4
>+#define GEN_DSS_PER_CSLICE 8
>+#define GEN_DSS_PER_MSLICE 8
>+
> struct sseu_dev_info {
> u8 slice_mask;
> u8 subslice_mask[GEN_MAX_SLICES * GEN_MAX_SUBSLICE_STRIDE];
>@@ -104,4 +108,6 @@ void intel_sseu_dump(const struct sseu_dev_info *sseu, struct drm_printer *p);
> void intel_sseu_print_topology(const struct sseu_dev_info *sseu,
> struct drm_printer *p);
>
>+u16 intel_slicemask_from_dssmask(u64 dss_mask, int dss_per_slice);
>+
> #endif /* __INTEL_SSEU_H__ */
>diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
>index 9173df59821a..f2ceabb0e2ea 100644
>--- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
>+++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
>@@ -889,12 +889,24 @@ cfl_gt_workarounds_init(struct drm_i915_private *i915, struct i915_wa_list *wal)
> GAMT_ECO_ENABLE_IN_PLACE_DECOMPRESS);
> }
>
>+static void __add_mcr_wa(struct drm_i915_private *i915, struct i915_wa_list *wal,
>+ unsigned slice, unsigned subslice)
>+{
>+ u32 mcr, mcr_mask;
>+
>+ mcr = GEN11_MCR_SLICE(slice) | GEN11_MCR_SUBSLICE(subslice);
>+ mcr_mask = GEN11_MCR_SLICE_MASK | GEN11_MCR_SUBSLICE_MASK;
>+
>+ drm_dbg(&i915->drm, "MCR slice/subslice = %x\n", mcr);
>+
>+ wa_write_clr_set(wal, GEN8_MCR_SELECTOR, mcr_mask, mcr);
>+}
>+
> static void
> icl_wa_init_mcr(struct drm_i915_private *i915, struct i915_wa_list *wal)
> {
> const struct sseu_dev_info *sseu = &i915->gt.info.sseu;
> unsigned int slice, subslice;
>- u32 mcr, mcr_mask;
>
> GEM_BUG_ON(GRAPHICS_VER(i915) < 11);
> GEM_BUG_ON(hweight8(sseu->slice_mask) > 1);
>@@ -919,12 +931,79 @@ icl_wa_init_mcr(struct drm_i915_private *i915, struct i915_wa_list *wal)
> if (i915->gt.info.l3bank_mask & BIT(subslice))
> i915->gt.steering_table[L3BANK] = NULL;
>
>- mcr = GEN11_MCR_SLICE(slice) | GEN11_MCR_SUBSLICE(subslice);
>- mcr_mask = GEN11_MCR_SLICE_MASK | GEN11_MCR_SUBSLICE_MASK;
>+ __add_mcr_wa(i915, wal, slice, subslice);
>+}
>
>- drm_dbg(&i915->drm, "MCR slice/subslice = %x\n", mcr);
>+__maybe_unused
>+static void
>+xehp_init_mcr(struct intel_gt *gt, struct i915_wa_list *wal)
>+{
>+ struct drm_i915_private *i915 = gt->i915;
>+ const struct sseu_dev_info *sseu = &gt->info.sseu;
>+ unsigned long slice, subslice = 0, slice_mask = 0;
>+ u64 dss_mask = 0;
>+ u32 lncf_mask = 0;
>+ int i;
>
>- wa_write_clr_set(wal, GEN8_MCR_SELECTOR, mcr_mask, mcr);
>+ /*
>+ * On Xe_HP the steering increases in complexity. There are now several
>+ * more units that require steering and we're not guaranteed to be able
>+ * to find a common setting for all of them. These are:
>+ * - GSLICE (fusable)
>+ * - DSS (sub-unit within gslice; fusable)
>+ * - L3 Bank (fusable)
>+ * - MSLICE (fusable)
>+ * - LNCF (sub-unit within mslice; always present if mslice is present)
>+ * - SQIDI (always on)
>+ *
>+ * We'll do our default/implicit steering based on GSLICE (in the
>+ * sliceid field) and DSS (in the subsliceid field). If we can
>+ * find overlap between the valid MSLICE and/or LNCF values with
>+ * a suitable GSLICE, then we can just re-use the default value and
>+ * skip and explicit steering at runtime.
>+ *
>+ * We only need to look for overlap between GSLICE/MSLICE/LNCF to find
>+ * a valid sliceid value. DSS steering is the only type of steering
>+ * that utilizes the 'subsliceid' bits.
>+ *
>+ * Also note that, even though the steering domain is called "GSlice"
>+ * and it is encoded in the register using the gslice format, the spec
>+ * says that the combined (geometry | compute) fuse should be used to
>+ * select the steering.
>+ */
>+
>+ /* Find the potential gslice candidates */
>+ dss_mask = intel_sseu_get_subslices(sseu, 0);
>+ slice_mask = intel_slicemask_from_dssmask(dss_mask, GEN_DSS_PER_GSLICE);
>+
>+ /*
>+ * Find the potential LNCF candidates. Either LNCF within a valid
>+ * mslice is fine.
>+ */
>+ for_each_set_bit(i, &gt->info.mslice_mask, GEN12_MAX_MSLICES)
>+ lncf_mask |= (0x3 << (i * 2));
>+
>+ /*
>+ * Are there any sliceid values that work for both GSLICE and LNCF
>+ * steering?
>+ */
>+ if (slice_mask & lncf_mask) {
>+ slice_mask &= lncf_mask;
>+ gt->steering_table[LNCF] = NULL;
>+ }
>+
>+ /* How about sliceid values that also work for MSLICE steering? */
>+ if (slice_mask & gt->info.mslice_mask) {
>+ slice_mask &= gt->info.mslice_mask;
>+ gt->steering_table[MSLICE] = NULL;
>+ }
>+
>+ slice = __ffs(slice_mask);
>+ subslice = __ffs(dss_mask >> (slice * GEN_DSS_PER_GSLICE));
>+ WARN_ON(subslice > GEN_DSS_PER_GSLICE);
>+ WARN_ON(dss_mask >> (slice * GEN_DSS_PER_GSLICE) == 0);
>+
>+ __add_mcr_wa(i915, wal, slice, subslice);
> }
>
> static void
>diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>index 70bef688c6da..31b8bb43c581 100644
>--- a/drivers/gpu/drm/i915/i915_drv.h
>+++ b/drivers/gpu/drm/i915/i915_drv.h
>@@ -1694,6 +1694,9 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
> #define HAS_RUNTIME_PM(dev_priv) (INTEL_INFO(dev_priv)->has_runtime_pm)
> #define HAS_64BIT_RELOC(dev_priv) (INTEL_INFO(dev_priv)->has_64bit_reloc)
>
>+#define HAS_MSLICES(dev_priv) \
>+ (INTEL_INFO(dev_priv)->has_mslices)
>+
> #define HAS_IPC(dev_priv) (INTEL_INFO(dev_priv)->display.has_ipc)
>
> #define HAS_REGION(i915, i) (INTEL_INFO(i915)->memory_regions & (i))
>diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
>index 08651ca03478..ed9edda727d2 100644
>--- a/drivers/gpu/drm/i915/i915_pci.c
>+++ b/drivers/gpu/drm/i915/i915_pci.c
>@@ -1007,6 +1007,7 @@ static const struct intel_device_info adl_p_info = {
> .has_llc = 1, \
> .has_logical_ring_contexts = 1, \
> .has_logical_ring_elsq = 1, \
>+ .has_mslices = 1, \
> .has_rc6 = 1, \
> .has_reset_engine = 1, \
> .has_rps = 1, \
>diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
>index 1a164b90e9fc..f4113e7e8271 100644
>--- a/drivers/gpu/drm/i915/i915_reg.h
>+++ b/drivers/gpu/drm/i915/i915_reg.h
>@@ -2766,6 +2766,7 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
> #define GEN11_MCR_SLICE_MASK GEN11_MCR_SLICE(0xf)
> #define GEN11_MCR_SUBSLICE(subslice) (((subslice) & 0x7) << 24)
> #define GEN11_MCR_SUBSLICE_MASK GEN11_MCR_SUBSLICE(0x7)
>+#define GEN11_MCR_MULTICAST REG_BIT(31)

this is not used anywhere so we could just omit it. If we are adding to
have the complete definition for the register, this needs to be before
GEN11_MCR_SLICE() to adhere to the rules of definiting the most
significant bit first.

other than that, patch looks fine to me. It took me some time to review
and understand the table, the steering rules, etc. But AFAICS this seems
to follow them

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>

Lucas De Marchi

> #define RING_IPEIR(base) _MMIO((base) + 0x64)
> #define RING_IPEHR(base) _MMIO((base) + 0x68)
> #define RING_EIR(base) _MMIO((base) + 0xb0)
>@@ -3184,6 +3185,9 @@ static inline bool i915_mmio_reg_valid(i915_reg_t reg)
> #define GEN10_MIRROR_FUSE3 _MMIO(0x9118)
> #define GEN10_L3BANK_PAIR_COUNT 4
> #define GEN10_L3BANK_MASK 0x0F
>+/* on Xe_HP the same fuses indicates mslices instead of L3 banks */
>+#define GEN12_MAX_MSLICES 4
>+#define GEN12_MEML3_EN_MASK 0x0F
>
> #define GEN8_EU_DISABLE0 _MMIO(0x9134)
> #define GEN8_EU_DIS0_S0_MASK 0xffffff
>diff --git a/drivers/gpu/drm/i915/intel_device_info.h b/drivers/gpu/drm/i915/intel_device_info.h
>index 121d6d9afd3a..2177372f9ac3 100644
>--- a/drivers/gpu/drm/i915/intel_device_info.h
>+++ b/drivers/gpu/drm/i915/intel_device_info.h
>@@ -133,6 +133,7 @@ enum intel_ppgtt_type {
> func(has_llc); \
> func(has_logical_ring_contexts); \
> func(has_logical_ring_elsq); \
>+ func(has_mslices); \
> func(has_pooled_eu); \
> func(has_rc6); \
> func(has_rc6p); \
>--
>2.25.4
>
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