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Diffstat (limited to 'drivers/gpu/drm/xe/xe_gt_mcr.c')
-rw-r--r--drivers/gpu/drm/xe/xe_gt_mcr.c685
1 files changed, 685 insertions, 0 deletions
diff --git a/drivers/gpu/drm/xe/xe_gt_mcr.c b/drivers/gpu/drm/xe/xe_gt_mcr.c
new file mode 100644
index 000000000..8546cd3cc
--- /dev/null
+++ b/drivers/gpu/drm/xe/xe_gt_mcr.c
@@ -0,0 +1,685 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2022 Intel Corporation
+ */
+
+#include "xe_gt_mcr.h"
+
+#include "regs/xe_gt_regs.h"
+#include "xe_gt.h"
+#include "xe_gt_topology.h"
+#include "xe_gt_types.h"
+#include "xe_mmio.h"
+
+/**
+ * DOC: GT Multicast/Replicated (MCR) Register Support
+ *
+ * Some GT registers are designed as "multicast" or "replicated" registers:
+ * multiple instances of the same register share a single MMIO offset. MCR
+ * registers are generally used when the hardware needs to potentially track
+ * independent values of a register per hardware unit (e.g., per-subslice,
+ * per-L3bank, etc.). The specific types of replication that exist vary
+ * per-platform.
+ *
+ * MMIO accesses to MCR registers are controlled according to the settings
+ * programmed in the platform's MCR_SELECTOR register(s). MMIO writes to MCR
+ * registers can be done in either multicast (a single write updates all
+ * instances of the register to the same value) or unicast (a write updates only
+ * one specific instance) form. Reads of MCR registers always operate in a
+ * unicast manner regardless of how the multicast/unicast bit is set in
+ * MCR_SELECTOR. Selection of a specific MCR instance for unicast operations is
+ * referred to as "steering."
+ *
+ * If MCR register operations are steered toward a hardware unit that is
+ * fused off or currently powered down due to power gating, the MMIO operation
+ * is "terminated" by the hardware. Terminated read operations will return a
+ * value of zero and terminated unicast write operations will be silently
+ * ignored. During device initialization, the goal of the various
+ * ``init_steering_*()`` functions is to apply the platform-specific rules for
+ * each MCR register type to identify a steering target that will select a
+ * non-terminated instance.
+ */
+
+#define STEER_SEMAPHORE XE_REG(0xFD0)
+
+static inline struct xe_reg to_xe_reg(struct xe_reg_mcr reg_mcr)
+{
+ return reg_mcr.__reg;
+}
+
+enum {
+ MCR_OP_READ,
+ MCR_OP_WRITE
+};
+
+static const struct xe_mmio_range xelp_l3bank_steering_table[] = {
+ { 0x00B100, 0x00B3FF },
+ {},
+};
+
+static const struct xe_mmio_range xehp_l3bank_steering_table[] = {
+ { 0x008C80, 0x008CFF },
+ { 0x00B100, 0x00B3FF },
+ {},
+};
+
+/*
+ * Although the bspec lists more "MSLICE" ranges than shown here, some of those
+ * are of a "GAM" subclass that has special rules and doesn't need to be
+ * included here.
+ */
+static const struct xe_mmio_range xehp_mslice_steering_table[] = {
+ { 0x00DD00, 0x00DDFF },
+ { 0x00E900, 0x00FFFF }, /* 0xEA00 - OxEFFF is unused */
+ {},
+};
+
+static const struct xe_mmio_range xehp_lncf_steering_table[] = {
+ { 0x00B000, 0x00B0FF },
+ { 0x00D880, 0x00D8FF },
+ {},
+};
+
+/*
+ * We have several types of MCR registers where steering to (0,0) will always
+ * provide us with a non-terminated value. We'll stick them all in the same
+ * table for simplicity.
+ */
+static const struct xe_mmio_range xehpc_instance0_steering_table[] = {
+ { 0x004000, 0x004AFF }, /* HALF-BSLICE */
+ { 0x008800, 0x00887F }, /* CC */
+ { 0x008A80, 0x008AFF }, /* TILEPSMI */
+ { 0x00B000, 0x00B0FF }, /* HALF-BSLICE */
+ { 0x00B100, 0x00B3FF }, /* L3BANK */
+ { 0x00C800, 0x00CFFF }, /* HALF-BSLICE */
+ { 0x00D800, 0x00D8FF }, /* HALF-BSLICE */
+ { 0x00DD00, 0x00DDFF }, /* BSLICE */
+ { 0x00E900, 0x00E9FF }, /* HALF-BSLICE */
+ { 0x00EC00, 0x00EEFF }, /* HALF-BSLICE */
+ { 0x00F000, 0x00FFFF }, /* HALF-BSLICE */
+ { 0x024180, 0x0241FF }, /* HALF-BSLICE */
+ {},
+};
+
+static const struct xe_mmio_range xelpg_instance0_steering_table[] = {
+ { 0x000B00, 0x000BFF }, /* SQIDI */
+ { 0x001000, 0x001FFF }, /* SQIDI */
+ { 0x004000, 0x0048FF }, /* GAM */
+ { 0x008700, 0x0087FF }, /* SQIDI */
+ { 0x00B000, 0x00B0FF }, /* NODE */
+ { 0x00C800, 0x00CFFF }, /* GAM */
+ { 0x00D880, 0x00D8FF }, /* NODE */
+ { 0x00DD00, 0x00DDFF }, /* OAAL2 */
+ {},
+};
+
+static const struct xe_mmio_range xelpg_l3bank_steering_table[] = {
+ { 0x00B100, 0x00B3FF },
+ {},
+};
+
+static const struct xe_mmio_range xelp_dss_steering_table[] = {
+ { 0x008150, 0x00815F },
+ { 0x009520, 0x00955F },
+ { 0x00DE80, 0x00E8FF },
+ { 0x024A00, 0x024A7F },
+ {},
+};
+
+/* DSS steering is used for GSLICE ranges as well */
+static const struct xe_mmio_range xehp_dss_steering_table[] = {
+ { 0x005200, 0x0052FF }, /* GSLICE */
+ { 0x005400, 0x007FFF }, /* GSLICE */
+ { 0x008140, 0x00815F }, /* GSLICE (0x8140-0x814F), DSS (0x8150-0x815F) */
+ { 0x008D00, 0x008DFF }, /* DSS */
+ { 0x0094D0, 0x00955F }, /* GSLICE (0x94D0-0x951F), DSS (0x9520-0x955F) */
+ { 0x009680, 0x0096FF }, /* DSS */
+ { 0x00D800, 0x00D87F }, /* GSLICE */
+ { 0x00DC00, 0x00DCFF }, /* GSLICE */
+ { 0x00DE80, 0x00E8FF }, /* DSS (0xE000-0xE0FF reserved ) */
+ { 0x017000, 0x017FFF }, /* GSLICE */
+ { 0x024A00, 0x024A7F }, /* DSS */
+ {},
+};
+
+/* DSS steering is used for COMPUTE ranges as well */
+static const struct xe_mmio_range xehpc_dss_steering_table[] = {
+ { 0x008140, 0x00817F }, /* COMPUTE (0x8140-0x814F & 0x8160-0x817F), DSS (0x8150-0x815F) */
+ { 0x0094D0, 0x00955F }, /* COMPUTE (0x94D0-0x951F), DSS (0x9520-0x955F) */
+ { 0x009680, 0x0096FF }, /* DSS */
+ { 0x00DC00, 0x00DCFF }, /* COMPUTE */
+ { 0x00DE80, 0x00E7FF }, /* DSS (0xDF00-0xE1FF reserved ) */
+ {},
+};
+
+/* DSS steering is used for SLICE ranges as well */
+static const struct xe_mmio_range xelpg_dss_steering_table[] = {
+ { 0x005200, 0x0052FF }, /* SLICE */
+ { 0x005500, 0x007FFF }, /* SLICE */
+ { 0x008140, 0x00815F }, /* SLICE (0x8140-0x814F), DSS (0x8150-0x815F) */
+ { 0x0094D0, 0x00955F }, /* SLICE (0x94D0-0x951F), DSS (0x9520-0x955F) */
+ { 0x009680, 0x0096FF }, /* DSS */
+ { 0x00D800, 0x00D87F }, /* SLICE */
+ { 0x00DC00, 0x00DCFF }, /* SLICE */
+ { 0x00DE80, 0x00E8FF }, /* DSS (0xE000-0xE0FF reserved) */
+ {},
+};
+
+static const struct xe_mmio_range xelpmp_oaddrm_steering_table[] = {
+ { 0x393200, 0x39323F },
+ { 0x393400, 0x3934FF },
+ {},
+};
+
+static const struct xe_mmio_range dg2_implicit_steering_table[] = {
+ { 0x000B00, 0x000BFF }, /* SF (SQIDI replication) */
+ { 0x001000, 0x001FFF }, /* SF (SQIDI replication) */
+ { 0x004000, 0x004AFF }, /* GAM (MSLICE replication) */
+ { 0x008700, 0x0087FF }, /* MCFG (SQIDI replication) */
+ { 0x00C800, 0x00CFFF }, /* GAM (MSLICE replication) */
+ { 0x00F000, 0x00FFFF }, /* GAM (MSLICE replication) */
+ {},
+};
+
+static const struct xe_mmio_range xe2lpg_dss_steering_table[] = {
+ { 0x005200, 0x0052FF }, /* SLICE */
+ { 0x005500, 0x007FFF }, /* SLICE */
+ { 0x008140, 0x00815F }, /* SLICE (0x8140-0x814F), DSS (0x8150-0x815F) */
+ { 0x0094D0, 0x00955F }, /* SLICE (0x94D0-0x951F), DSS (0x9520-0x955F) */
+ { 0x009680, 0x0096FF }, /* DSS */
+ { 0x00D800, 0x00D87F }, /* SLICE */
+ { 0x00DC00, 0x00DCFF }, /* SLICE */
+ { 0x00DE80, 0x00E8FF }, /* DSS (0xE000-0xE0FF reserved) */
+ { 0x00E980, 0x00E9FF }, /* SLICE */
+ { 0x013000, 0x0133FF }, /* DSS (0x13000-0x131FF), SLICE (0x13200-0x133FF) */
+ {},
+};
+
+static const struct xe_mmio_range xe2lpg_sqidi_psmi_steering_table[] = {
+ { 0x000B00, 0x000BFF },
+ { 0x001000, 0x001FFF },
+ {},
+};
+
+static const struct xe_mmio_range xe2lpg_instance0_steering_table[] = {
+ { 0x004000, 0x004AFF }, /* GAM, rsvd, GAMWKR */
+ { 0x008700, 0x00887F }, /* SQIDI, MEMPIPE */
+ { 0x00B000, 0x00B3FF }, /* NODE, L3BANK */
+ { 0x00C800, 0x00CFFF }, /* GAM */
+ { 0x00D880, 0x00D8FF }, /* NODE */
+ { 0x00DD00, 0x00DDFF }, /* MEMPIPE */
+ { 0x00E900, 0x00E97F }, /* MEMPIPE */
+ { 0x00F000, 0x00FFFF }, /* GAM, GAMWKR */
+ { 0x013400, 0x0135FF }, /* MEMPIPE */
+ {},
+};
+
+static const struct xe_mmio_range xe2lpm_gpmxmt_steering_table[] = {
+ { 0x388160, 0x38817F },
+ { 0x389480, 0x3894CF },
+ {},
+};
+
+static const struct xe_mmio_range xe2lpm_instance0_steering_table[] = {
+ { 0x384000, 0x3847DF }, /* GAM, rsvd, GAM */
+ { 0x384900, 0x384AFF }, /* GAM */
+ { 0x389560, 0x3895FF }, /* MEDIAINF */
+ { 0x38B600, 0x38B8FF }, /* L3BANK */
+ { 0x38C800, 0x38D07F }, /* GAM, MEDIAINF */
+ { 0x38F000, 0x38F0FF }, /* GAM */
+ { 0x393C00, 0x393C7F }, /* MEDIAINF */
+ {},
+};
+
+static void init_steering_l3bank(struct xe_gt *gt)
+{
+ if (GRAPHICS_VERx100(gt_to_xe(gt)) >= 1270) {
+ u32 mslice_mask = REG_FIELD_GET(MEML3_EN_MASK,
+ xe_mmio_read32(gt, MIRROR_FUSE3));
+ u32 bank_mask = REG_FIELD_GET(GT_L3_EXC_MASK,
+ xe_mmio_read32(gt, XEHP_FUSE4));
+
+ /*
+ * Group selects mslice, instance selects bank within mslice.
+ * Bank 0 is always valid _except_ when the bank mask is 010b.
+ */
+ gt->steering[L3BANK].group_target = __ffs(mslice_mask);
+ gt->steering[L3BANK].instance_target =
+ bank_mask & BIT(0) ? 0 : 2;
+ } else if (gt_to_xe(gt)->info.platform == XE_DG2) {
+ u32 mslice_mask = REG_FIELD_GET(MEML3_EN_MASK,
+ xe_mmio_read32(gt, MIRROR_FUSE3));
+ u32 bank = __ffs(mslice_mask) * 8;
+
+ /*
+ * Like mslice registers, look for a valid mslice and steer to
+ * the first L3BANK of that quad. Access to the Nth L3 bank is
+ * split between the first bits of group and instance
+ */
+ gt->steering[L3BANK].group_target = (bank >> 2) & 0x7;
+ gt->steering[L3BANK].instance_target = bank & 0x3;
+ } else {
+ u32 fuse = REG_FIELD_GET(L3BANK_MASK,
+ ~xe_mmio_read32(gt, MIRROR_FUSE3));
+
+ gt->steering[L3BANK].group_target = 0; /* unused */
+ gt->steering[L3BANK].instance_target = __ffs(fuse);
+ }
+}
+
+static void init_steering_mslice(struct xe_gt *gt)
+{
+ u32 mask = REG_FIELD_GET(MEML3_EN_MASK,
+ xe_mmio_read32(gt, MIRROR_FUSE3));
+
+ /*
+ * mslice registers are valid (not terminated) if either the meml3
+ * associated with the mslice is present, or at least one DSS associated
+ * with the mslice is present. There will always be at least one meml3
+ * so we can just use that to find a non-terminated mslice and ignore
+ * the DSS fusing.
+ */
+ gt->steering[MSLICE].group_target = __ffs(mask);
+ gt->steering[MSLICE].instance_target = 0; /* unused */
+
+ /*
+ * LNCF termination is also based on mslice presence, so we'll set
+ * it up here. Either LNCF within a non-terminated mslice will work,
+ * so we just always pick LNCF 0 here.
+ */
+ gt->steering[LNCF].group_target = __ffs(mask) << 1;
+ gt->steering[LNCF].instance_target = 0; /* unused */
+}
+
+static void init_steering_dss(struct xe_gt *gt)
+{
+ unsigned int dss = min(xe_dss_mask_group_ffs(gt->fuse_topo.g_dss_mask, 0, 0),
+ xe_dss_mask_group_ffs(gt->fuse_topo.c_dss_mask, 0, 0));
+ unsigned int dss_per_grp = gt_to_xe(gt)->info.platform == XE_PVC ? 8 : 4;
+
+ gt->steering[DSS].group_target = dss / dss_per_grp;
+ gt->steering[DSS].instance_target = dss % dss_per_grp;
+}
+
+static void init_steering_oaddrm(struct xe_gt *gt)
+{
+ /*
+ * First instance is only terminated if the entire first media slice
+ * is absent (i.e., no VCS0 or VECS0).
+ */
+ if (gt->info.engine_mask & (XE_HW_ENGINE_VCS0 | XE_HW_ENGINE_VECS0))
+ gt->steering[OADDRM].group_target = 0;
+ else
+ gt->steering[OADDRM].group_target = 1;
+
+ gt->steering[DSS].instance_target = 0; /* unused */
+}
+
+static void init_steering_sqidi_psmi(struct xe_gt *gt)
+{
+ u32 mask = REG_FIELD_GET(XE2_NODE_ENABLE_MASK,
+ xe_mmio_read32(gt, MIRROR_FUSE3));
+ u32 select = __ffs(mask);
+
+ gt->steering[SQIDI_PSMI].group_target = select >> 1;
+ gt->steering[SQIDI_PSMI].instance_target = select & 0x1;
+}
+
+static void init_steering_inst0(struct xe_gt *gt)
+{
+ gt->steering[DSS].group_target = 0; /* unused */
+ gt->steering[DSS].instance_target = 0; /* unused */
+}
+
+static const struct {
+ const char *name;
+ void (*init)(struct xe_gt *gt);
+} xe_steering_types[] = {
+ [L3BANK] = { "L3BANK", init_steering_l3bank },
+ [MSLICE] = { "MSLICE", init_steering_mslice },
+ [LNCF] = { "LNCF", NULL }, /* initialized by mslice init */
+ [DSS] = { "DSS", init_steering_dss },
+ [OADDRM] = { "OADDRM / GPMXMT", init_steering_oaddrm },
+ [SQIDI_PSMI] = { "SQIDI_PSMI", init_steering_sqidi_psmi },
+ [INSTANCE0] = { "INSTANCE 0", init_steering_inst0 },
+ [IMPLICIT_STEERING] = { "IMPLICIT", NULL },
+};
+
+void xe_gt_mcr_init(struct xe_gt *gt)
+{
+ struct xe_device *xe = gt_to_xe(gt);
+
+ BUILD_BUG_ON(IMPLICIT_STEERING + 1 != NUM_STEERING_TYPES);
+ BUILD_BUG_ON(ARRAY_SIZE(xe_steering_types) != NUM_STEERING_TYPES);
+
+ spin_lock_init(&gt->mcr_lock);
+
+ if (gt->info.type == XE_GT_TYPE_MEDIA) {
+ drm_WARN_ON(&xe->drm, MEDIA_VER(xe) < 13);
+
+ if (MEDIA_VER(xe) >= 20) {
+ gt->steering[OADDRM].ranges = xe2lpm_gpmxmt_steering_table;
+ gt->steering[INSTANCE0].ranges = xe2lpm_instance0_steering_table;
+ } else {
+ gt->steering[OADDRM].ranges = xelpmp_oaddrm_steering_table;
+ }
+ } else {
+ if (GRAPHICS_VER(xe) >= 20) {
+ gt->steering[DSS].ranges = xe2lpg_dss_steering_table;
+ gt->steering[SQIDI_PSMI].ranges = xe2lpg_sqidi_psmi_steering_table;
+ gt->steering[INSTANCE0].ranges = xe2lpg_instance0_steering_table;
+ } else if (GRAPHICS_VERx100(xe) >= 1270) {
+ gt->steering[INSTANCE0].ranges = xelpg_instance0_steering_table;
+ gt->steering[L3BANK].ranges = xelpg_l3bank_steering_table;
+ gt->steering[DSS].ranges = xelpg_dss_steering_table;
+ } else if (xe->info.platform == XE_PVC) {
+ gt->steering[INSTANCE0].ranges = xehpc_instance0_steering_table;
+ gt->steering[DSS].ranges = xehpc_dss_steering_table;
+ } else if (xe->info.platform == XE_DG2) {
+ gt->steering[L3BANK].ranges = xehp_l3bank_steering_table;
+ gt->steering[MSLICE].ranges = xehp_mslice_steering_table;
+ gt->steering[LNCF].ranges = xehp_lncf_steering_table;
+ gt->steering[DSS].ranges = xehp_dss_steering_table;
+ gt->steering[IMPLICIT_STEERING].ranges = dg2_implicit_steering_table;
+ } else {
+ gt->steering[L3BANK].ranges = xelp_l3bank_steering_table;
+ gt->steering[DSS].ranges = xelp_dss_steering_table;
+ }
+ }
+
+ /* Select non-terminated steering target for each type */
+ for (int i = 0; i < NUM_STEERING_TYPES; i++)
+ if (gt->steering[i].ranges && xe_steering_types[i].init)
+ xe_steering_types[i].init(gt);
+}
+
+/**
+ * xe_gt_mcr_set_implicit_defaults - Initialize steer control registers
+ * @gt: GT structure
+ *
+ * Some register ranges don't need to have their steering control registers
+ * changed on each access - it's sufficient to set them once on initialization.
+ * This function sets those registers for each platform *
+ */
+void xe_gt_mcr_set_implicit_defaults(struct xe_gt *gt)
+{
+ struct xe_device *xe = gt_to_xe(gt);
+
+ if (xe->info.platform == XE_DG2) {
+ u32 steer_val = REG_FIELD_PREP(MCR_SLICE_MASK, 0) |
+ REG_FIELD_PREP(MCR_SUBSLICE_MASK, 2);
+
+ xe_mmio_write32(gt, MCFG_MCR_SELECTOR, steer_val);
+ xe_mmio_write32(gt, SF_MCR_SELECTOR, steer_val);
+ /*
+ * For GAM registers, all reads should be directed to instance 1
+ * (unicast reads against other instances are not allowed),
+ * and instance 1 is already the hardware's default steering
+ * target, which we never change
+ */
+ }
+}
+
+/*
+ * xe_gt_mcr_get_nonterminated_steering - find group/instance values that
+ * will steer a register to a non-terminated instance
+ * @gt: GT structure
+ * @reg: register for which the steering is required
+ * @group: return variable for group steering
+ * @instance: return variable for instance steering
+ *
+ * This function returns a group/instance pair that is guaranteed to work for
+ * read steering of the given register. Note that a value will be returned even
+ * if the register is not replicated and therefore does not actually require
+ * steering.
+ *
+ * Returns true if the caller should steer to the @group/@instance values
+ * returned. Returns false if the caller need not perform any steering
+ */
+static bool xe_gt_mcr_get_nonterminated_steering(struct xe_gt *gt,
+ struct xe_reg_mcr reg_mcr,
+ u8 *group, u8 *instance)
+{
+ const struct xe_reg reg = to_xe_reg(reg_mcr);
+ const struct xe_mmio_range *implicit_ranges;
+
+ for (int type = 0; type < IMPLICIT_STEERING; type++) {
+ if (!gt->steering[type].ranges)
+ continue;
+
+ for (int i = 0; gt->steering[type].ranges[i].end > 0; i++) {
+ if (xe_mmio_in_range(gt, &gt->steering[type].ranges[i], reg)) {
+ *group = gt->steering[type].group_target;
+ *instance = gt->steering[type].instance_target;
+ return true;
+ }
+ }
+ }
+
+ implicit_ranges = gt->steering[IMPLICIT_STEERING].ranges;
+ if (implicit_ranges)
+ for (int i = 0; implicit_ranges[i].end > 0; i++)
+ if (xe_mmio_in_range(gt, &implicit_ranges[i], reg))
+ return false;
+
+ /*
+ * Not found in a steering table and not a register with implicit
+ * steering. Just steer to 0/0 as a guess and raise a warning.
+ */
+ drm_WARN(&gt_to_xe(gt)->drm, true,
+ "Did not find MCR register %#x in any MCR steering table\n",
+ reg.addr);
+ *group = 0;
+ *instance = 0;
+
+ return true;
+}
+
+/*
+ * Obtain exclusive access to MCR steering. On MTL and beyond we also need
+ * to synchronize with external clients (e.g., firmware), so a semaphore
+ * register will also need to be taken.
+ */
+static void mcr_lock(struct xe_gt *gt) __acquires(&gt->mcr_lock)
+{
+ struct xe_device *xe = gt_to_xe(gt);
+ int ret = 0;
+
+ spin_lock(&gt->mcr_lock);
+
+ /*
+ * Starting with MTL we also need to grab a semaphore register
+ * to synchronize with external agents (e.g., firmware) that now
+ * shares the same steering control register. The semaphore is obtained
+ * when a read to the relevant register returns 1.
+ */
+ if (GRAPHICS_VERx100(xe) >= 1270)
+ ret = xe_mmio_wait32(gt, STEER_SEMAPHORE, 0x1, 0x1, 10, NULL,
+ true);
+
+ drm_WARN_ON_ONCE(&xe->drm, ret == -ETIMEDOUT);
+}
+
+static void mcr_unlock(struct xe_gt *gt) __releases(&gt->mcr_lock)
+{
+ /* Release hardware semaphore - this is done by writing 1 to the register */
+ if (GRAPHICS_VERx100(gt_to_xe(gt)) >= 1270)
+ xe_mmio_write32(gt, STEER_SEMAPHORE, 0x1);
+
+ spin_unlock(&gt->mcr_lock);
+}
+
+/*
+ * Access a register with specific MCR steering
+ *
+ * Caller needs to make sure the relevant forcewake wells are up.
+ */
+static u32 rw_with_mcr_steering(struct xe_gt *gt, struct xe_reg_mcr reg_mcr,
+ u8 rw_flag, int group, int instance, u32 value)
+{
+ const struct xe_reg reg = to_xe_reg(reg_mcr);
+ struct xe_reg steer_reg;
+ u32 steer_val, val = 0;
+
+ lockdep_assert_held(&gt->mcr_lock);
+
+ if (GRAPHICS_VERx100(gt_to_xe(gt)) >= 1270) {
+ steer_reg = MTL_MCR_SELECTOR;
+ steer_val = REG_FIELD_PREP(MTL_MCR_GROUPID, group) |
+ REG_FIELD_PREP(MTL_MCR_INSTANCEID, instance);
+ } else {
+ steer_reg = MCR_SELECTOR;
+ steer_val = REG_FIELD_PREP(MCR_SLICE_MASK, group) |
+ REG_FIELD_PREP(MCR_SUBSLICE_MASK, instance);
+ }
+
+ /*
+ * Always leave the hardware in multicast mode when doing reads and only
+ * change it to unicast mode when doing writes of a specific instance.
+ *
+ * The setting of the multicast/unicast bit usually wouldn't matter for
+ * read operations (which always return the value from a single register
+ * instance regardless of how that bit is set), but some platforms may
+ * have workarounds requiring us to remain in multicast mode for reads,
+ * e.g. Wa_22013088509 on PVC. There's no real downside to this, so
+ * we'll just go ahead and do so on all platforms; we'll only clear the
+ * multicast bit from the mask when explicitly doing a write operation.
+ *
+ * No need to save old steering reg value.
+ */
+ if (rw_flag == MCR_OP_READ)
+ steer_val |= MCR_MULTICAST;
+
+ xe_mmio_write32(gt, steer_reg, steer_val);
+
+ if (rw_flag == MCR_OP_READ)
+ val = xe_mmio_read32(gt, reg);
+ else
+ xe_mmio_write32(gt, reg, value);
+
+ /*
+ * If we turned off the multicast bit (during a write) we're required
+ * to turn it back on before finishing. The group and instance values
+ * don't matter since they'll be re-programmed on the next MCR
+ * operation.
+ */
+ if (rw_flag == MCR_OP_WRITE)
+ xe_mmio_write32(gt, steer_reg, MCR_MULTICAST);
+
+ return val;
+}
+
+/**
+ * xe_gt_mcr_unicast_read_any - reads a non-terminated instance of an MCR register
+ * @gt: GT structure
+ * @reg_mcr: register to read
+ *
+ * Reads a GT MCR register. The read will be steered to a non-terminated
+ * instance (i.e., one that isn't fused off or powered down by power gating).
+ * This function assumes the caller is already holding any necessary forcewake
+ * domains.
+ *
+ * Returns the value from a non-terminated instance of @reg.
+ */
+u32 xe_gt_mcr_unicast_read_any(struct xe_gt *gt, struct xe_reg_mcr reg_mcr)
+{
+ const struct xe_reg reg = to_xe_reg(reg_mcr);
+ u8 group, instance;
+ u32 val;
+ bool steer;
+
+ steer = xe_gt_mcr_get_nonterminated_steering(gt, reg_mcr,
+ &group, &instance);
+
+ if (steer) {
+ mcr_lock(gt);
+ val = rw_with_mcr_steering(gt, reg_mcr, MCR_OP_READ,
+ group, instance, 0);
+ mcr_unlock(gt);
+ } else {
+ val = xe_mmio_read32(gt, reg);
+ }
+
+ return val;
+}
+
+/**
+ * xe_gt_mcr_unicast_read - read a specific instance of an MCR register
+ * @gt: GT structure
+ * @reg_mcr: the MCR register to read
+ * @group: the MCR group
+ * @instance: the MCR instance
+ *
+ * Returns the value read from an MCR register after steering toward a specific
+ * group/instance.
+ */
+u32 xe_gt_mcr_unicast_read(struct xe_gt *gt,
+ struct xe_reg_mcr reg_mcr,
+ int group, int instance)
+{
+ u32 val;
+
+ mcr_lock(gt);
+ val = rw_with_mcr_steering(gt, reg_mcr, MCR_OP_READ, group, instance, 0);
+ mcr_unlock(gt);
+
+ return val;
+}
+
+/**
+ * xe_gt_mcr_unicast_write - write a specific instance of an MCR register
+ * @gt: GT structure
+ * @reg_mcr: the MCR register to write
+ * @value: value to write
+ * @group: the MCR group
+ * @instance: the MCR instance
+ *
+ * Write an MCR register in unicast mode after steering toward a specific
+ * group/instance.
+ */
+void xe_gt_mcr_unicast_write(struct xe_gt *gt, struct xe_reg_mcr reg_mcr,
+ u32 value, int group, int instance)
+{
+ mcr_lock(gt);
+ rw_with_mcr_steering(gt, reg_mcr, MCR_OP_WRITE, group, instance, value);
+ mcr_unlock(gt);
+}
+
+/**
+ * xe_gt_mcr_multicast_write - write a value to all instances of an MCR register
+ * @gt: GT structure
+ * @reg_mcr: the MCR register to write
+ * @value: value to write
+ *
+ * Write an MCR register in multicast mode to update all instances.
+ */
+void xe_gt_mcr_multicast_write(struct xe_gt *gt, struct xe_reg_mcr reg_mcr,
+ u32 value)
+{
+ struct xe_reg reg = to_xe_reg(reg_mcr);
+
+ /*
+ * Synchronize with any unicast operations. Once we have exclusive
+ * access, the MULTICAST bit should already be set, so there's no need
+ * to touch the steering register.
+ */
+ mcr_lock(gt);
+ xe_mmio_write32(gt, reg, value);
+ mcr_unlock(gt);
+}
+
+void xe_gt_mcr_steering_dump(struct xe_gt *gt, struct drm_printer *p)
+{
+ for (int i = 0; i < NUM_STEERING_TYPES; i++) {
+ if (gt->steering[i].ranges) {
+ drm_printf(p, "%s steering: group=%#x, instance=%#x\n",
+ xe_steering_types[i].name,
+ gt->steering[i].group_target,
+ gt->steering[i].instance_target);
+ for (int j = 0; gt->steering[i].ranges[j].end; j++)
+ drm_printf(p, "\t0x%06x - 0x%06x\n",
+ gt->steering[i].ranges[j].start,
+ gt->steering[i].ranges[j].end);
+ }
+ }
+}