Re: [PATCH 2/9] Revert "drm/msm/a6xx: Use the DMA API for GMU memory objects"

[Jonathan Marek <jonathan@marek.ca>]

On 4/20/20 3:51 PM, Bjorn Andersson wrote:
> On Mon 20 Apr 07:03 PDT 2020, Jonathan Marek wrote:
> 
>> This reverts commit a5fb8b918920c6f7706a8b5b8ea535a7f077a7f6.
> 
> Why?
> 

It removes something I need for the next patches in the series, however 
I'm open to suggestions on a better solution (Jordan said he would check 
it out)

>> ---
>>   drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 115 +++++++++++++++++++++++---
>>   drivers/gpu/drm/msm/adreno/a6xx_gmu.h |   6 +-
>>   2 files changed, 107 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
>> index c4e71abbdd53..748cd379065f 100644
>> --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
>> @@ -2,7 +2,6 @@
>>   /* Copyright (c) 2017-2019 The Linux Foundation. All rights reserved. */
>>   
>>   #include <linux/clk.h>
>> -#include <linux/dma-mapping.h>
>>   #include <linux/interconnect.h>
>>   #include <linux/pm_domain.h>
>>   #include <linux/pm_opp.h>
>> @@ -921,10 +920,21 @@ int a6xx_gmu_stop(struct a6xx_gpu *a6xx_gpu)
>>   
>>   static void a6xx_gmu_memory_free(struct a6xx_gmu *gmu, struct a6xx_gmu_bo *bo)
>>   {
>> +	int count, i;
>> +	u64 iova;
>> +
>>   	if (IS_ERR_OR_NULL(bo))
>>   		return;
>>   
>> -	dma_free_wc(gmu->dev, bo->size, bo->virt, bo->iova);
>> +	count = bo->size >> PAGE_SHIFT;
>> +	iova = bo->iova;
>> +
>> +	for (i = 0; i < count; i++, iova += PAGE_SIZE) {
>> +		iommu_unmap(gmu->domain, iova, PAGE_SIZE);
>> +		__free_pages(bo->pages[i], 0);
>> +	}
>> +
>> +	kfree(bo->pages);
>>   	kfree(bo);
>>   }
>>   
>> @@ -932,6 +942,7 @@ static struct a6xx_gmu_bo *a6xx_gmu_memory_alloc(struct a6xx_gmu *gmu,
>>   		size_t size)
>>   {
>>   	struct a6xx_gmu_bo *bo;
>> +	int ret, count, i;
>>   
>>   	bo = kzalloc(sizeof(*bo), GFP_KERNEL);
>>   	if (!bo)
>> @@ -939,14 +950,86 @@ static struct a6xx_gmu_bo *a6xx_gmu_memory_alloc(struct a6xx_gmu *gmu,
>>   
>>   	bo->size = PAGE_ALIGN(size);
>>   
>> -	bo->virt = dma_alloc_wc(gmu->dev, bo->size, &bo->iova, GFP_KERNEL);
>> +	count = bo->size >> PAGE_SHIFT;
>>   
>> -	if (!bo->virt) {
>> +	bo->pages = kcalloc(count, sizeof(struct page *), GFP_KERNEL);
>> +	if (!bo->pages) {
>>   		kfree(bo);
>>   		return ERR_PTR(-ENOMEM);
>>   	}
>>   
>> +	for (i = 0; i < count; i++) {
>> +		bo->pages[i] = alloc_page(GFP_KERNEL);
>> +		if (!bo->pages[i])
>> +			goto err;
>> +	}
>> +
>> +	bo->iova = gmu->uncached_iova_base;
>> +
>> +	for (i = 0; i < count; i++) {
>> +		ret = iommu_map(gmu->domain,
>> +			bo->iova + (PAGE_SIZE * i),
>> +			page_to_phys(bo->pages[i]), PAGE_SIZE,
>> +			IOMMU_READ | IOMMU_WRITE);
>> +
>> +		if (ret) {
>> +			DRM_DEV_ERROR(gmu->dev, "Unable to map GMU buffer object\n");
>> +
>> +			for (i = i - 1 ; i >= 0; i--)
>> +				iommu_unmap(gmu->domain,
>> +					bo->iova + (PAGE_SIZE * i),
>> +					PAGE_SIZE);
>> +
>> +			goto err;
>> +		}
>> +	}
>> +
>> +	bo->virt = vmap(bo->pages, count, VM_IOREMAP,
>> +		pgprot_writecombine(PAGE_KERNEL));
>> +	if (!bo->virt)
>> +		goto err;
>> +
>> +	/* Align future IOVA addresses on 1MB boundaries */
>> +	gmu->uncached_iova_base += ALIGN(size, SZ_1M);
>> +
>>   	return bo;
>> +
>> +err:
>> +	for (i = 0; i < count; i++) {
>> +		if (bo->pages[i])
>> +			__free_pages(bo->pages[i], 0);
>> +	}
>> +
>> +	kfree(bo->pages);
>> +	kfree(bo);
>> +
>> +	return ERR_PTR(-ENOMEM);
>> +}
>> +
>> +static int a6xx_gmu_memory_probe(struct a6xx_gmu *gmu)
>> +{
>> +	int ret;
>> +
>> +	/*
>> +	 * The GMU address space is hardcoded to treat the range
>> +	 * 0x60000000 - 0x80000000 as un-cached memory. All buffers shared
>> +	 * between the GMU and the CPU will live in this space
>> +	 */
>> +	gmu->uncached_iova_base = 0x60000000;
>> +
>> +
>> +	gmu->domain = iommu_domain_alloc(&platform_bus_type);
>> +	if (!gmu->domain)
>> +		return -ENODEV;
>> +
>> +	ret = iommu_attach_device(gmu->domain, gmu->dev);
>> +
>> +	if (ret) {
>> +		iommu_domain_free(gmu->domain);
>> +		gmu->domain = NULL;
>> +	}
>> +
>> +	return ret;
>>   }
>>   
>>   /* Return the 'arc-level' for the given frequency */
>> @@ -1206,6 +1289,10 @@ void a6xx_gmu_remove(struct a6xx_gpu *a6xx_gpu)
>>   
>>   	a6xx_gmu_memory_free(gmu, gmu->hfi);
>>   
>> +	iommu_detach_device(gmu->domain, gmu->dev);
>> +
>> +	iommu_domain_free(gmu->domain);
>> +
>>   	free_irq(gmu->gmu_irq, gmu);
>>   	free_irq(gmu->hfi_irq, gmu);
>>   
>> @@ -1226,15 +1313,7 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
>>   
>>   	gmu->dev = &pdev->dev;
>>   
>> -	/* Pass force_dma false to require the DT to set the dma region */
>> -	ret = of_dma_configure(gmu->dev, node, false);
>> -	if (ret)
>> -		return ret;
>> -
>> -	/* Set the mask after the of_dma_configure() */
>> -	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(31));
>> -	if (ret)
>> -		return ret;
>> +	of_dma_configure(gmu->dev, node, true);
>>   
>>   	/* Fow now, don't do anything fancy until we get our feet under us */
>>   	gmu->idle_level = GMU_IDLE_STATE_ACTIVE;
>> @@ -1246,6 +1325,11 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
>>   	if (ret)
>>   		goto err_put_device;
>>   
>> +	/* Set up the IOMMU context bank */
>> +	ret = a6xx_gmu_memory_probe(gmu);
>> +	if (ret)
>> +		goto err_put_device;
>> +
>>   	/* Allocate memory for for the HFI queues */
>>   	gmu->hfi = a6xx_gmu_memory_alloc(gmu, SZ_16K);
>>   	if (IS_ERR(gmu->hfi))
>> @@ -1291,6 +1375,11 @@ int a6xx_gmu_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
>>   err_memory:
>>   	a6xx_gmu_memory_free(gmu, gmu->hfi);
>>   
>> +	if (gmu->domain) {
>> +		iommu_detach_device(gmu->domain, gmu->dev);
>> +
>> +		iommu_domain_free(gmu->domain);
>> +	}
>>   	ret = -ENODEV;
>>   
>>   err_put_device:
>> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
>> index 4af65a36d5ca..2af91ed7ed0c 100644
>> --- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.h
>> @@ -12,7 +12,8 @@
>>   struct a6xx_gmu_bo {
>>   	void *virt;
>>   	size_t size;
>> -	dma_addr_t iova;
>> +	u64 iova;
>> +	struct page **pages;
>>   };
>>   
>>   /*
>> @@ -48,6 +49,9 @@ struct a6xx_gmu {
>>   	int hfi_irq;
>>   	int gmu_irq;
>>   
>> +	struct iommu_domain *domain;
>> +	u64 uncached_iova_base;
>> +
>>   	struct device *gxpd;
>>   
>>   	int idle_level;
>> -- 
>> 2.26.1
>>
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