diff options
Diffstat (limited to 'drivers/gpu/drm/etnaviv/etnaviv_gpu.c')
-rw-r--r-- | drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 406 |
1 files changed, 190 insertions, 216 deletions
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c index 21d0d22f1168..8a88799bf79b 100644 --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c @@ -26,19 +26,21 @@ #include "etnaviv_gem.h" #include "etnaviv_mmu.h" #include "etnaviv_perfmon.h" +#include "etnaviv_sched.h" #include "common.xml.h" #include "state.xml.h" #include "state_hi.xml.h" #include "cmdstream.xml.h" +#ifndef PHYS_OFFSET +#define PHYS_OFFSET 0 +#endif + static const struct platform_device_id gpu_ids[] = { { .name = "etnaviv-gpu,2d" }, { }, }; -static bool etnaviv_dump_core = true; -module_param_named(dump_core, etnaviv_dump_core, bool, 0600); - /* * Driver functions: */ @@ -82,6 +84,30 @@ int etnaviv_gpu_get_param(struct etnaviv_gpu *gpu, u32 param, u64 *value) *value = gpu->identity.minor_features5; break; + case ETNAVIV_PARAM_GPU_FEATURES_7: + *value = gpu->identity.minor_features6; + break; + + case ETNAVIV_PARAM_GPU_FEATURES_8: + *value = gpu->identity.minor_features7; + break; + + case ETNAVIV_PARAM_GPU_FEATURES_9: + *value = gpu->identity.minor_features8; + break; + + case ETNAVIV_PARAM_GPU_FEATURES_10: + *value = gpu->identity.minor_features9; + break; + + case ETNAVIV_PARAM_GPU_FEATURES_11: + *value = gpu->identity.minor_features10; + break; + + case ETNAVIV_PARAM_GPU_FEATURES_12: + *value = gpu->identity.minor_features11; + break; + case ETNAVIV_PARAM_GPU_STREAM_COUNT: *value = gpu->identity.stream_count; break; @@ -348,6 +374,13 @@ static void etnaviv_hw_identify(struct etnaviv_gpu *gpu) dev_info(gpu->dev, "model: GC%x, revision: %x\n", gpu->identity.model, gpu->identity.revision); + /* + * If there is a match in the HWDB, we aren't interested in the + * remaining register values, as they might be wrong. + */ + if (etnaviv_fill_identity_from_hwdb(gpu)) + return; + gpu->identity.features = gpu_read(gpu, VIVS_HI_CHIP_FEATURE); /* Disable fast clear on GC700. */ @@ -448,9 +481,14 @@ static int etnaviv_hw_reset(struct etnaviv_gpu *gpu) control |= VIVS_HI_CLOCK_CONTROL_ISOLATE_GPU; gpu_write(gpu, VIVS_HI_CLOCK_CONTROL, control); - /* set soft reset. */ - control |= VIVS_HI_CLOCK_CONTROL_SOFT_RESET; - gpu_write(gpu, VIVS_HI_CLOCK_CONTROL, control); + if (gpu->sec_mode == ETNA_SEC_KERNEL) { + gpu_write(gpu, VIVS_MMUv2_AHB_CONTROL, + VIVS_MMUv2_AHB_CONTROL_RESET); + } else { + /* set soft reset. */ + control |= VIVS_HI_CLOCK_CONTROL_SOFT_RESET; + gpu_write(gpu, VIVS_HI_CLOCK_CONTROL, control); + } /* wait for reset. */ usleep_range(10, 20); @@ -561,6 +599,12 @@ void etnaviv_gpu_start_fe(struct etnaviv_gpu *gpu, u32 address, u16 prefetch) gpu_write(gpu, VIVS_FE_COMMAND_CONTROL, VIVS_FE_COMMAND_CONTROL_ENABLE | VIVS_FE_COMMAND_CONTROL_PREFETCH(prefetch)); + + if (gpu->sec_mode == ETNA_SEC_KERNEL) { + gpu_write(gpu, VIVS_MMUv2_SEC_COMMAND_CONTROL, + VIVS_MMUv2_SEC_COMMAND_CONTROL_ENABLE | + VIVS_MMUv2_SEC_COMMAND_CONTROL_PREFETCH(prefetch)); + } } static void etnaviv_gpu_setup_pulse_eater(struct etnaviv_gpu *gpu) @@ -634,6 +678,12 @@ static void etnaviv_gpu_hw_init(struct etnaviv_gpu *gpu) gpu_write(gpu, VIVS_MC_BUS_CONFIG, bus_config); } + if (gpu->sec_mode == ETNA_SEC_KERNEL) { + u32 val = gpu_read(gpu, VIVS_MMUv2_AHB_CONTROL); + val |= VIVS_MMUv2_AHB_CONTROL_NONSEC_ACCESS; + gpu_write(gpu, VIVS_MMUv2_AHB_CONTROL, val); + } + /* setup the pulse eater */ etnaviv_gpu_setup_pulse_eater(gpu); @@ -696,6 +746,14 @@ int etnaviv_gpu_init(struct etnaviv_gpu *gpu) gpu->identity.features &= ~chipFeatures_FAST_CLEAR; } + /* + * On cores with security features supported, we claim control over the + * security states. + */ + if ((gpu->identity.minor_features7 & chipMinorFeatures7_BIT_SECURITY) && + (gpu->identity.minor_features10 & chipMinorFeatures10_SECURITY_AHB)) + gpu->sec_mode = ETNA_SEC_KERNEL; + ret = etnaviv_hw_reset(gpu); if (ret) { dev_err(gpu->dev, "GPU reset failed\n"); @@ -807,6 +865,8 @@ int etnaviv_gpu_debugfs(struct etnaviv_gpu *gpu, struct seq_file *m) verify_dma(gpu, &debug); seq_puts(m, "\tfeatures\n"); + seq_printf(m, "\t major_features: 0x%08x\n", + gpu->identity.features); seq_printf(m, "\t minor_features0: 0x%08x\n", gpu->identity.minor_features0); seq_printf(m, "\t minor_features1: 0x%08x\n", @@ -819,6 +879,18 @@ int etnaviv_gpu_debugfs(struct etnaviv_gpu *gpu, struct seq_file *m) gpu->identity.minor_features4); seq_printf(m, "\t minor_features5: 0x%08x\n", gpu->identity.minor_features5); + seq_printf(m, "\t minor_features6: 0x%08x\n", + gpu->identity.minor_features6); + seq_printf(m, "\t minor_features7: 0x%08x\n", + gpu->identity.minor_features7); + seq_printf(m, "\t minor_features8: 0x%08x\n", + gpu->identity.minor_features8); + seq_printf(m, "\t minor_features9: 0x%08x\n", + gpu->identity.minor_features9); + seq_printf(m, "\t minor_features10: 0x%08x\n", + gpu->identity.minor_features10); + seq_printf(m, "\t minor_features11: 0x%08x\n", + gpu->identity.minor_features11); seq_puts(m, "\tspecs\n"); seq_printf(m, "\t stream_count: %d\n", @@ -912,38 +984,24 @@ int etnaviv_gpu_debugfs(struct etnaviv_gpu *gpu, struct seq_file *m) } #endif -/* - * Hangcheck detection for locked gpu: - */ -static void recover_worker(struct work_struct *work) +void etnaviv_gpu_recover_hang(struct etnaviv_gpu *gpu) { - struct etnaviv_gpu *gpu = container_of(work, struct etnaviv_gpu, - recover_work); unsigned long flags; unsigned int i = 0; - dev_err(gpu->dev, "hangcheck recover!\n"); + dev_err(gpu->dev, "recover hung GPU!\n"); if (pm_runtime_get_sync(gpu->dev) < 0) return; mutex_lock(&gpu->lock); - /* Only catch the first event, or when manually re-armed */ - if (etnaviv_dump_core) { - etnaviv_core_dump(gpu); - etnaviv_dump_core = false; - } - etnaviv_hw_reset(gpu); /* complete all events, the GPU won't do it after the reset */ spin_lock_irqsave(&gpu->event_spinlock, flags); - for_each_set_bit_from(i, gpu->event_bitmap, ETNA_NR_EVENTS) { - dma_fence_signal(gpu->event[i].fence); - gpu->event[i].fence = NULL; + for_each_set_bit_from(i, gpu->event_bitmap, ETNA_NR_EVENTS) complete(&gpu->event_free); - } bitmap_zero(gpu->event_bitmap, ETNA_NR_EVENTS); spin_unlock_irqrestore(&gpu->event_spinlock, flags); gpu->completed_fence = gpu->active_fence; @@ -955,56 +1013,6 @@ static void recover_worker(struct work_struct *work) mutex_unlock(&gpu->lock); pm_runtime_mark_last_busy(gpu->dev); pm_runtime_put_autosuspend(gpu->dev); - - /* Retire the buffer objects in a work */ - queue_work(gpu->wq, &gpu->retire_work); -} - -static void hangcheck_timer_reset(struct etnaviv_gpu *gpu) -{ - DBG("%s", dev_name(gpu->dev)); - mod_timer(&gpu->hangcheck_timer, - round_jiffies_up(jiffies + DRM_ETNAVIV_HANGCHECK_JIFFIES)); -} - -static void hangcheck_handler(struct timer_list *t) -{ - struct etnaviv_gpu *gpu = from_timer(gpu, t, hangcheck_timer); - u32 fence = gpu->completed_fence; - bool progress = false; - - if (fence != gpu->hangcheck_fence) { - gpu->hangcheck_fence = fence; - progress = true; - } - - if (!progress) { - u32 dma_addr = gpu_read(gpu, VIVS_FE_DMA_ADDRESS); - int change = dma_addr - gpu->hangcheck_dma_addr; - - if (change < 0 || change > 16) { - gpu->hangcheck_dma_addr = dma_addr; - progress = true; - } - } - - if (!progress && fence_after(gpu->active_fence, fence)) { - dev_err(gpu->dev, "hangcheck detected gpu lockup!\n"); - dev_err(gpu->dev, " completed fence: %u\n", fence); - dev_err(gpu->dev, " active fence: %u\n", - gpu->active_fence); - queue_work(gpu->wq, &gpu->recover_work); - } - - /* if still more pending work, reset the hangcheck timer: */ - if (fence_after(gpu->active_fence, gpu->hangcheck_fence)) - hangcheck_timer_reset(gpu); -} - -static void hangcheck_disable(struct etnaviv_gpu *gpu) -{ - del_timer_sync(&gpu->hangcheck_timer); - cancel_work_sync(&gpu->recover_work); } /* fence object management */ @@ -1080,54 +1088,6 @@ static struct dma_fence *etnaviv_gpu_fence_alloc(struct etnaviv_gpu *gpu) return &f->base; } -int etnaviv_gpu_fence_sync_obj(struct etnaviv_gem_object *etnaviv_obj, - unsigned int context, bool exclusive, bool explicit) -{ - struct reservation_object *robj = etnaviv_obj->resv; - struct reservation_object_list *fobj; - struct dma_fence *fence; - int i, ret; - - if (!exclusive) { - ret = reservation_object_reserve_shared(robj); - if (ret) - return ret; - } - - if (explicit) - return 0; - - /* - * If we have any shared fences, then the exclusive fence - * should be ignored as it will already have been signalled. - */ - fobj = reservation_object_get_list(robj); - if (!fobj || fobj->shared_count == 0) { - /* Wait on any existing exclusive fence which isn't our own */ - fence = reservation_object_get_excl(robj); - if (fence && fence->context != context) { - ret = dma_fence_wait(fence, true); - if (ret) - return ret; - } - } - - if (!exclusive || !fobj) - return 0; - - for (i = 0; i < fobj->shared_count; i++) { - fence = rcu_dereference_protected(fobj->shared[i], - reservation_object_held(robj)); - if (fence->context != context) { - ret = dma_fence_wait(fence, true); - if (ret) - return ret; - } - } - - return 0; -} - /* * event management: */ @@ -1194,67 +1154,47 @@ static void event_free(struct etnaviv_gpu *gpu, unsigned int event) /* * Cmdstream submission/retirement: */ - -static void retire_worker(struct work_struct *work) -{ - struct etnaviv_gpu *gpu = container_of(work, struct etnaviv_gpu, - retire_work); - u32 fence = gpu->completed_fence; - struct etnaviv_gem_submit *submit, *tmp; - LIST_HEAD(retire_list); - - mutex_lock(&gpu->lock); - list_for_each_entry_safe(submit, tmp, &gpu->active_submit_list, node) { - if (!dma_fence_is_signaled(submit->out_fence)) - break; - - list_move(&submit->node, &retire_list); - } - - gpu->retired_fence = fence; - - mutex_unlock(&gpu->lock); - - list_for_each_entry_safe(submit, tmp, &retire_list, node) - etnaviv_submit_put(submit); -} - int etnaviv_gpu_wait_fence_interruptible(struct etnaviv_gpu *gpu, - u32 fence, struct timespec *timeout) + u32 id, struct timespec *timeout) { + struct dma_fence *fence; int ret; - if (fence_after(fence, gpu->next_fence)) { - DRM_ERROR("waiting on invalid fence: %u (of %u)\n", - fence, gpu->next_fence); - return -EINVAL; - } + /* + * Look up the fence and take a reference. We might still find a fence + * whose refcount has already dropped to zero. dma_fence_get_rcu + * pretends we didn't find a fence in that case. + */ + rcu_read_lock(); + fence = idr_find(&gpu->fence_idr, id); + if (fence) + fence = dma_fence_get_rcu(fence); + rcu_read_unlock(); + + if (!fence) + return 0; if (!timeout) { /* No timeout was requested: just test for completion */ - ret = fence_completed(gpu, fence) ? 0 : -EBUSY; + ret = dma_fence_is_signaled(fence) ? 0 : -EBUSY; } else { unsigned long remaining = etnaviv_timeout_to_jiffies(timeout); - ret = wait_event_interruptible_timeout(gpu->fence_event, - fence_completed(gpu, fence), - remaining); - if (ret == 0) { - DBG("timeout waiting for fence: %u (retired: %u completed: %u)", - fence, gpu->retired_fence, - gpu->completed_fence); + ret = dma_fence_wait_timeout(fence, true, remaining); + if (ret == 0) ret = -ETIMEDOUT; - } else if (ret != -ERESTARTSYS) { + else if (ret != -ERESTARTSYS) ret = 0; - } + } + dma_fence_put(fence); return ret; } /* * Wait for an object to become inactive. This, on it's own, is not race - * free: the object is moved by the retire worker off the active list, and + * free: the object is moved by the scheduler off the active list, and * then the iova is put. Moreover, the object could be re-submitted just * after we notice that it's become inactive. * @@ -1343,16 +1283,19 @@ static void sync_point_perfmon_sample_post(struct etnaviv_gpu *gpu, /* add bo's to gpu's ring, and kick gpu: */ -int etnaviv_gpu_submit(struct etnaviv_gpu *gpu, - struct etnaviv_gem_submit *submit) +struct dma_fence *etnaviv_gpu_submit(struct etnaviv_gem_submit *submit) { + struct etnaviv_gpu *gpu = submit->gpu; + struct dma_fence *gpu_fence; unsigned int i, nr_events = 1, event[3]; int ret; - ret = pm_runtime_get_sync(gpu->dev); - if (ret < 0) - return ret; - submit->runtime_resumed = true; + if (!submit->runtime_resumed) { + ret = pm_runtime_get_sync(gpu->dev); + if (ret < 0) + return NULL; + submit->runtime_resumed = true; + } /* * if there are performance monitor requests we need to have @@ -1367,21 +1310,20 @@ int etnaviv_gpu_submit(struct etnaviv_gpu *gpu, ret = event_alloc(gpu, nr_events, event); if (ret) { DRM_ERROR("no free events\n"); - return ret; + return NULL; } mutex_lock(&gpu->lock); - submit->out_fence = etnaviv_gpu_fence_alloc(gpu); - if (!submit->out_fence) { + gpu_fence = etnaviv_gpu_fence_alloc(gpu); + if (!gpu_fence) { for (i = 0; i < nr_events; i++) event_free(gpu, event[i]); - ret = -ENOMEM; goto out_unlock; } - gpu->active_fence = submit->out_fence->seqno; + gpu->active_fence = gpu_fence->seqno; if (submit->nr_pmrs) { gpu->event[event[1]].sync_point = &sync_point_perfmon_sample_pre; @@ -1390,8 +1332,8 @@ int etnaviv_gpu_submit(struct etnaviv_gpu *gpu, etnaviv_sync_point_queue(gpu, event[1]); } - kref_get(&submit->refcount); - gpu->event[event[0]].fence = submit->out_fence; + gpu->event[event[0]].fence = gpu_fence; + submit->cmdbuf.user_size = submit->cmdbuf.size - 8; etnaviv_buffer_queue(gpu, submit->exec_state, event[0], &submit->cmdbuf); @@ -1402,15 +1344,10 @@ int etnaviv_gpu_submit(struct etnaviv_gpu *gpu, etnaviv_sync_point_queue(gpu, event[2]); } - list_add_tail(&submit->node, &gpu->active_submit_list); - - hangcheck_timer_reset(gpu); - ret = 0; - out_unlock: mutex_unlock(&gpu->lock); - return ret; + return gpu_fence; } static void sync_point_worker(struct work_struct *work) @@ -1428,9 +1365,35 @@ static void sync_point_worker(struct work_struct *work) etnaviv_gpu_start_fe(gpu, addr + 2, 2); } -/* - * Init/Cleanup: - */ +static void dump_mmu_fault(struct etnaviv_gpu *gpu) +{ + u32 status_reg, status; + int i; + + if (gpu->sec_mode == ETNA_SEC_NONE) + status_reg = VIVS_MMUv2_STATUS; + else + status_reg = VIVS_MMUv2_SEC_STATUS; + + status = gpu_read(gpu, status_reg); + dev_err_ratelimited(gpu->dev, "MMU fault status 0x%08x\n", status); + + for (i = 0; i < 4; i++) { + u32 address_reg; + + if (!(status & (VIVS_MMUv2_STATUS_EXCEPTION0__MASK << (i * 4)))) + continue; + + if (gpu->sec_mode == ETNA_SEC_NONE) + address_reg = VIVS_MMUv2_EXCEPTION_ADDR(i); + else + address_reg = VIVS_MMUv2_SEC_EXCEPTION_ADDR; + + dev_err_ratelimited(gpu->dev, "MMU %d fault addr 0x%08x\n", i, + gpu_read(gpu, address_reg)); + } +} + static irqreturn_t irq_handler(int irq, void *data) { struct etnaviv_gpu *gpu = data; @@ -1451,17 +1414,7 @@ static irqreturn_t irq_handler(int irq, void *data) } if (intr & VIVS_HI_INTR_ACKNOWLEDGE_MMU_EXCEPTION) { - int i; - - dev_err_ratelimited(gpu->dev, - "MMU fault status 0x%08x\n", - gpu_read(gpu, VIVS_MMUv2_STATUS)); - for (i = 0; i < 4; i++) { - dev_err_ratelimited(gpu->dev, - "MMU %d fault addr 0x%08x\n", - i, gpu_read(gpu, - VIVS_MMUv2_EXCEPTION_ADDR(i))); - } + dump_mmu_fault(gpu); intr &= ~VIVS_HI_INTR_ACKNOWLEDGE_MMU_EXCEPTION; } @@ -1484,7 +1437,6 @@ static irqreturn_t irq_handler(int irq, void *data) continue; gpu->event[event].fence = NULL; - dma_fence_signal(fence); /* * Events can be processed out of order. Eg, @@ -1497,13 +1449,11 @@ static irqreturn_t irq_handler(int irq, void *data) */ if (fence_after(fence->seqno, gpu->completed_fence)) gpu->completed_fence = fence->seqno; + dma_fence_signal(fence); event_free(gpu, event); } - /* Retire the buffer objects in a work */ - queue_work(gpu->wq, &gpu->retire_work); - ret = IRQ_HANDLED; } @@ -1514,6 +1464,12 @@ static int etnaviv_gpu_clk_enable(struct etnaviv_gpu *gpu) { int ret; + if (gpu->clk_reg) { + ret = clk_prepare_enable(gpu->clk_reg); + if (ret) + return ret; + } + if (gpu->clk_bus) { ret = clk_prepare_enable(gpu->clk_bus); if (ret) @@ -1552,6 +1508,8 @@ static int etnaviv_gpu_clk_disable(struct etnaviv_gpu *gpu) clk_disable_unprepare(gpu->clk_core); if (gpu->clk_bus) clk_disable_unprepare(gpu->clk_bus); + if (gpu->clk_reg) + clk_disable_unprepare(gpu->clk_reg); return 0; } @@ -1675,41 +1633,49 @@ static int etnaviv_gpu_bind(struct device *dev, struct device *master, gpu->wq = alloc_ordered_workqueue(dev_name(dev), 0); if (!gpu->wq) { - if (IS_ENABLED(CONFIG_DRM_ETNAVIV_THERMAL)) - thermal_cooling_device_unregister(gpu->cooling); - return -ENOMEM; + ret = -ENOMEM; + goto out_thermal; } + ret = etnaviv_sched_init(gpu); + if (ret) + goto out_workqueue; + #ifdef CONFIG_PM ret = pm_runtime_get_sync(gpu->dev); #else ret = etnaviv_gpu_clk_enable(gpu); #endif - if (ret < 0) { - destroy_workqueue(gpu->wq); - if (IS_ENABLED(CONFIG_DRM_ETNAVIV_THERMAL)) - thermal_cooling_device_unregister(gpu->cooling); - return ret; - } + if (ret < 0) + goto out_sched; + gpu->drm = drm; gpu->fence_context = dma_fence_context_alloc(1); + idr_init(&gpu->fence_idr); spin_lock_init(&gpu->fence_spinlock); - INIT_LIST_HEAD(&gpu->active_submit_list); - INIT_WORK(&gpu->retire_work, retire_worker); INIT_WORK(&gpu->sync_point_work, sync_point_worker); - INIT_WORK(&gpu->recover_work, recover_worker); init_waitqueue_head(&gpu->fence_event); - timer_setup(&gpu->hangcheck_timer, hangcheck_handler, TIMER_DEFERRABLE); - priv->gpu[priv->num_gpus++] = gpu; pm_runtime_mark_last_busy(gpu->dev); pm_runtime_put_autosuspend(gpu->dev); return 0; + +out_sched: + etnaviv_sched_fini(gpu); + +out_workqueue: + destroy_workqueue(gpu->wq); + +out_thermal: + if (IS_ENABLED(CONFIG_DRM_ETNAVIV_THERMAL)) + thermal_cooling_device_unregister(gpu->cooling); + + return ret; } static void etnaviv_gpu_unbind(struct device *dev, struct device *master, @@ -1719,11 +1685,11 @@ static void etnaviv_gpu_unbind(struct device *dev, struct device *master, DBG("%s", dev_name(gpu->dev)); - hangcheck_disable(gpu); - flush_workqueue(gpu->wq); destroy_workqueue(gpu->wq); + etnaviv_sched_fini(gpu); + #ifdef CONFIG_PM pm_runtime_get_sync(gpu->dev); pm_runtime_put_sync_suspend(gpu->dev); @@ -1745,6 +1711,7 @@ static void etnaviv_gpu_unbind(struct device *dev, struct device *master, } gpu->drm = NULL; + idr_destroy(&gpu->fence_idr); if (IS_ENABLED(CONFIG_DRM_ETNAVIV_THERMAL)) thermal_cooling_device_unregister(gpu->cooling); @@ -1762,6 +1729,7 @@ static const struct of_device_id etnaviv_gpu_match[] = { }, { /* sentinel */ } }; +MODULE_DEVICE_TABLE(of, etnaviv_gpu_match); static int etnaviv_gpu_platform_probe(struct platform_device *pdev) { @@ -1775,6 +1743,7 @@ static int etnaviv_gpu_platform_probe(struct platform_device *pdev) gpu->dev = &pdev->dev; mutex_init(&gpu->lock); + mutex_init(&gpu->fence_idr_lock); /* Map registers: */ gpu->mmio = etnaviv_ioremap(pdev, NULL, dev_name(gpu->dev)); @@ -1796,6 +1765,11 @@ static int etnaviv_gpu_platform_probe(struct platform_device *pdev) } /* Get Clocks: */ + gpu->clk_reg = devm_clk_get(&pdev->dev, "reg"); + DBG("clk_reg: %p", gpu->clk_reg); + if (IS_ERR(gpu->clk_reg)) + gpu->clk_reg = NULL; + gpu->clk_bus = devm_clk_get(&pdev->dev, "bus"); DBG("clk_bus: %p", gpu->clk_bus); if (IS_ERR(gpu->clk_bus)) |