diff options
Diffstat (limited to 'drivers/gpu/drm/i915/display/intel_dmc_wl.c')
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_dmc_wl.c | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_dmc_wl.c b/drivers/gpu/drm/i915/display/intel_dmc_wl.c new file mode 100644 index 000000000000..d9864b9cc429 --- /dev/null +++ b/drivers/gpu/drm/i915/display/intel_dmc_wl.c @@ -0,0 +1,264 @@ +// SPDX-License-Identifier: MIT +/* + * Copyright (C) 2024 Intel Corporation + */ + +#include <linux/kernel.h> + +#include "intel_de.h" +#include "intel_dmc.h" +#include "intel_dmc_regs.h" +#include "intel_dmc_wl.h" + +/** + * DOC: DMC wakelock support + * + * Wake lock is the mechanism to cause display engine to exit DC + * states to allow programming to registers that are powered down in + * those states. Previous projects exited DC states automatically when + * detecting programming. Now software controls the exit by + * programming the wake lock. This improves system performance and + * system interactions and better fits the flip queue style of + * programming. Wake lock is only required when DC5, DC6, or DC6v have + * been enabled in DC_STATE_EN and the wake lock mode of operation has + * been enabled. + * + * The wakelock mechanism in DMC allows the display engine to exit DC + * states explicitly before programming registers that may be powered + * down. In earlier hardware, this was done automatically and + * implicitly when the display engine accessed a register. With the + * wakelock implementation, the driver asserts a wakelock in DMC, + * which forces it to exit the DC state until the wakelock is + * deasserted. + * + * The mechanism can be enabled and disabled by writing to the + * DMC_WAKELOCK_CFG register. There are also 13 control registers + * that can be used to hold and release different wakelocks. In the + * current implementation, we only need one wakelock, so only + * DMC_WAKELOCK1_CTL is used. The other definitions are here for + * potential future use. + */ + +#define DMC_WAKELOCK_CTL_TIMEOUT 5 +#define DMC_WAKELOCK_HOLD_TIME 50 + +struct intel_dmc_wl_range { + u32 start; + u32 end; +}; + +static struct intel_dmc_wl_range lnl_wl_range[] = { + { .start = 0x60000, .end = 0x7ffff }, +}; + +static void __intel_dmc_wl_release(struct intel_display *display) +{ + struct drm_i915_private *i915 = to_i915(display->drm); + struct intel_dmc_wl *wl = &display->wl; + + WARN_ON(refcount_read(&wl->refcount)); + + queue_delayed_work(i915->unordered_wq, &wl->work, + msecs_to_jiffies(DMC_WAKELOCK_HOLD_TIME)); +} + +static void intel_dmc_wl_work(struct work_struct *work) +{ + struct intel_dmc_wl *wl = + container_of(work, struct intel_dmc_wl, work.work); + struct intel_display *display = + container_of(wl, struct intel_display, wl); + unsigned long flags; + + spin_lock_irqsave(&wl->lock, flags); + + /* Bail out if refcount reached zero while waiting for the spinlock */ + if (!refcount_read(&wl->refcount)) + goto out_unlock; + + __intel_de_rmw_nowl(display, DMC_WAKELOCK1_CTL, DMC_WAKELOCK_CTL_REQ, 0); + + if (__intel_de_wait_for_register_nowl(display, DMC_WAKELOCK1_CTL, + DMC_WAKELOCK_CTL_ACK, 0, + DMC_WAKELOCK_CTL_TIMEOUT)) { + WARN_RATELIMIT(1, "DMC wakelock release timed out"); + goto out_unlock; + } + + wl->taken = false; + +out_unlock: + spin_unlock_irqrestore(&wl->lock, flags); +} + +static bool intel_dmc_wl_check_range(u32 address) +{ + int i; + bool wl_needed = false; + + for (i = 0; i < ARRAY_SIZE(lnl_wl_range); i++) { + if (address >= lnl_wl_range[i].start && + address <= lnl_wl_range[i].end) { + wl_needed = true; + break; + } + } + + return wl_needed; +} + +static bool __intel_dmc_wl_supported(struct intel_display *display) +{ + struct drm_i915_private *i915 = to_i915(display->drm); + + if (DISPLAY_VER(display) < 20 || + !intel_dmc_has_payload(i915) || + !display->params.enable_dmc_wl) + return false; + + return true; +} + +void intel_dmc_wl_init(struct intel_display *display) +{ + struct intel_dmc_wl *wl = &display->wl; + + /* don't call __intel_dmc_wl_supported(), DMC is not loaded yet */ + if (DISPLAY_VER(display) < 20 || !display->params.enable_dmc_wl) + return; + + INIT_DELAYED_WORK(&wl->work, intel_dmc_wl_work); + spin_lock_init(&wl->lock); + refcount_set(&wl->refcount, 0); +} + +void intel_dmc_wl_enable(struct intel_display *display) +{ + struct intel_dmc_wl *wl = &display->wl; + unsigned long flags; + + if (!__intel_dmc_wl_supported(display)) + return; + + spin_lock_irqsave(&wl->lock, flags); + + if (wl->enabled) + goto out_unlock; + + /* + * Enable wakelock in DMC. We shouldn't try to take the + * wakelock, because we're just enabling it, so call the + * non-locking version directly here. + */ + __intel_de_rmw_nowl(display, DMC_WAKELOCK_CFG, 0, DMC_WAKELOCK_CFG_ENABLE); + + wl->enabled = true; + wl->taken = false; + +out_unlock: + spin_unlock_irqrestore(&wl->lock, flags); +} + +void intel_dmc_wl_disable(struct intel_display *display) +{ + struct intel_dmc_wl *wl = &display->wl; + unsigned long flags; + + if (!__intel_dmc_wl_supported(display)) + return; + + flush_delayed_work(&wl->work); + + spin_lock_irqsave(&wl->lock, flags); + + if (!wl->enabled) + goto out_unlock; + + /* Disable wakelock in DMC */ + __intel_de_rmw_nowl(display, DMC_WAKELOCK_CFG, DMC_WAKELOCK_CFG_ENABLE, 0); + + refcount_set(&wl->refcount, 0); + wl->enabled = false; + wl->taken = false; + +out_unlock: + spin_unlock_irqrestore(&wl->lock, flags); +} + +void intel_dmc_wl_get(struct intel_display *display, i915_reg_t reg) +{ + struct intel_dmc_wl *wl = &display->wl; + unsigned long flags; + + if (!__intel_dmc_wl_supported(display)) + return; + + if (!intel_dmc_wl_check_range(reg.reg)) + return; + + spin_lock_irqsave(&wl->lock, flags); + + if (!wl->enabled) + goto out_unlock; + + cancel_delayed_work(&wl->work); + + if (refcount_inc_not_zero(&wl->refcount)) + goto out_unlock; + + refcount_set(&wl->refcount, 1); + + /* + * Only try to take the wakelock if it's not marked as taken + * yet. It may be already taken at this point if we have + * already released the last reference, but the work has not + * run yet. + */ + if (!wl->taken) { + __intel_de_rmw_nowl(display, DMC_WAKELOCK1_CTL, 0, + DMC_WAKELOCK_CTL_REQ); + + if (__intel_de_wait_for_register_nowl(display, DMC_WAKELOCK1_CTL, + DMC_WAKELOCK_CTL_ACK, + DMC_WAKELOCK_CTL_ACK, + DMC_WAKELOCK_CTL_TIMEOUT)) { + WARN_RATELIMIT(1, "DMC wakelock ack timed out"); + goto out_unlock; + } + + wl->taken = true; + } + +out_unlock: + spin_unlock_irqrestore(&wl->lock, flags); +} + +void intel_dmc_wl_put(struct intel_display *display, i915_reg_t reg) +{ + struct intel_dmc_wl *wl = &display->wl; + unsigned long flags; + + if (!__intel_dmc_wl_supported(display)) + return; + + if (!intel_dmc_wl_check_range(reg.reg)) + return; + + spin_lock_irqsave(&wl->lock, flags); + + if (!wl->enabled) + goto out_unlock; + + if (WARN_RATELIMIT(!refcount_read(&wl->refcount), + "Tried to put wakelock with refcount zero\n")) + goto out_unlock; + + if (refcount_dec_and_test(&wl->refcount)) { + __intel_dmc_wl_release(display); + + goto out_unlock; + } + +out_unlock: + spin_unlock_irqrestore(&wl->lock, flags); +} |