linux-kernel - Re: [PATCH v3 4/5] soc: qcom: smem: Support dynamic item limit

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Date:   Wed, 11 Oct 2017 20:58:57 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Chris Lew <clew@...cinc.com>
Cc:     andy.gross@...aro.org, david.brown@...aro.org,
        aneela@...eaurora.org, linux-arm-msm@...r.kernel.org,
        linux-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
        clew@...eaurora.org
Subject: Re: [PATCH v3 4/5] soc: qcom: smem: Support dynamic item limit

On Wed 11 Oct 14:29 PDT 2017, Chris Lew wrote:

> From: Chris Lew <clew@...eaurora.org>
> 
> In V12 SMEM, SBL writes SMEM parameter information after the TOC. Use
> the SBL provided item count as the max item number.
> 

Acked-by: Bjorn Andersson <bjorn.andersson@...aro.org>

Regards,
Bjorn

> Signed-off-by: Chris Lew <clew@...eaurora.org>
> ---
> 
> Changes since v1:
> - Change num_items to __le16 from __le32
> - Move max smem item warning to generic get/alloc functions
> - Use get ptable helper function
> 
> Changes since v2:
> - Rename qcom_smem_get_dynamic_item to qcom_smem_get_item_count
> - Reduce subject to 50 chars and wrap summary to 72 chars
> 
>  drivers/soc/qcom/smem.c | 51 +++++++++++++++++++++++++++++++++++++++++++------
>  1 file changed, 45 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
> index 6a3134e9c591..19704baa65f4 100644
> --- a/drivers/soc/qcom/smem.c
> +++ b/drivers/soc/qcom/smem.c
> @@ -223,6 +223,24 @@ struct smem_private_entry {
>  #define SMEM_PRIVATE_CANARY	0xa5a5
>  
>  /**
> + * struct smem_info - smem region info located after the table of contents
> + * @magic:	magic number, must be SMEM_INFO_MAGIC
> + * @size:	size of the smem region
> + * @base_addr:	base address of the smem region
> + * @reserved:	for now reserved entry
> + * @num_items:	highest accepted item number
> + */
> +struct smem_info {
> +	u8 magic[4];
> +	__le32 size;
> +	__le32 base_addr;
> +	__le32 reserved;
> +	__le16 num_items;
> +};
> +
> +static const u8 SMEM_INFO_MAGIC[] = { 0x53, 0x49, 0x49, 0x49 }; /* SIII */
> +
> +/**
>   * struct smem_region - representation of a chunk of memory used for smem
>   * @aux_base:	identifier of aux_mem base
>   * @virt_base:	virtual base address of memory with this aux_mem identifier
> @@ -243,6 +261,7 @@ struct smem_region {
>   * @partitions:	list of pointers to partitions affecting the current
>   *		processor/host
>   * @cacheline:	list of cacheline sizes for each host
> + * @item_count: max accepted item number
>   * @num_regions: number of @regions
>   * @regions:	list of the memory regions defining the shared memory
>   */
> @@ -255,6 +274,7 @@ struct qcom_smem {
>  	size_t global_cacheline;
>  	struct smem_partition_header *partitions[SMEM_HOST_COUNT];
>  	size_t cacheline[SMEM_HOST_COUNT];
> +	u32 item_count;
>  
>  	unsigned num_regions;
>  	struct smem_region regions[0];
> @@ -386,9 +406,6 @@ static int qcom_smem_alloc_global(struct qcom_smem *smem,
>  	struct smem_global_entry *entry;
>  	struct smem_header *header;
>  
> -	if (WARN_ON(item >= SMEM_ITEM_COUNT))
> -		return -EINVAL;
> -
>  	header = smem->regions[0].virt_base;
>  	entry = &header->toc[item];
>  	if (entry->allocated)
> @@ -439,6 +456,9 @@ int qcom_smem_alloc(unsigned host, unsigned item, size_t size)
>  		return -EINVAL;
>  	}
>  
> +	if (WARN_ON(item >= __smem->item_count))
> +		return -EINVAL;
> +
>  	ret = hwspin_lock_timeout_irqsave(__smem->hwlock,
>  					  HWSPINLOCK_TIMEOUT,
>  					  &flags);
> @@ -471,9 +491,6 @@ static void *qcom_smem_get_global(struct qcom_smem *smem,
>  	u32 aux_base;
>  	unsigned i;
>  
> -	if (WARN_ON(item >= SMEM_ITEM_COUNT))
> -		return ERR_PTR(-EINVAL);
> -
>  	header = smem->regions[0].virt_base;
>  	entry = &header->toc[item];
>  	if (!entry->allocated)
> @@ -569,6 +586,9 @@ void *qcom_smem_get(unsigned host, unsigned item, size_t *size)
>  	if (!__smem)
>  		return ptr;
>  
> +	if (WARN_ON(item >= __smem->item_count))
> +		return ERR_PTR(-EINVAL);
> +
>  	ret = hwspin_lock_timeout_irqsave(__smem->hwlock,
>  					  HWSPINLOCK_TIMEOUT,
>  					  &flags);
> @@ -656,6 +676,22 @@ static struct smem_ptable *qcom_smem_get_ptable(struct qcom_smem *smem)
>  	return ptable;
>  }
>  
> +static u32 qcom_smem_get_item_count(struct qcom_smem *smem)
> +{
> +	struct smem_ptable *ptable;
> +	struct smem_info *info;
> +
> +	ptable = qcom_smem_get_ptable(smem);
> +	if (IS_ERR_OR_NULL(ptable))
> +		return SMEM_ITEM_COUNT;
> +
> +	info = (struct smem_info *)&ptable->entry[ptable->num_entries];
> +	if (memcmp(info->magic, SMEM_INFO_MAGIC, sizeof(info->magic)))
> +		return SMEM_ITEM_COUNT;
> +
> +	return le16_to_cpu(info->num_items);
> +}
> +
>  static int qcom_smem_set_global_partition(struct qcom_smem *smem)
>  {
>  	struct smem_partition_header *header;
> @@ -883,7 +919,10 @@ static int qcom_smem_probe(struct platform_device *pdev)
>  		ret = qcom_smem_set_global_partition(smem);
>  		if (ret < 0)
>  			return ret;
> +		smem->item_count = qcom_smem_get_item_count(smem);
> +		break;
>  	case SMEM_GLOBAL_HEAP_VERSION:
> +		smem->item_count = SMEM_ITEM_COUNT;
>  		break;
>  	default:
>  		dev_err(&pdev->dev, "Unsupported SMEM version 0x%x\n", version);
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>