Re: [PATCH v2 3/4] soc: qcom: smem: Support reserved-memory description

[Vladimir Zapolskiy]

Hi Bjorn,

On 9/30/21 9:21 PM, Bjorn Andersson wrote:
> Practically all modern Qualcomm platforms has a single reserved-memory
> region for SMEM. So rather than having to describe SMEM in the form of a
> node with a reference to a reserved-memory node, allow the SMEM device
> to be instantiated directly from the reserved-memory node.
>
> The current means of falling back to dereferencing the "memory-region"
> is kept as a fallback, if it's determined that the SMEM node is a
> reserved-memory node.
>
> The "qcom,smem" compatible is added to the reserved_mem_matches list, to
> allow the reserved-memory device to be probed.
>
> In order to retain the readability of the code, the resolution of
> resources is split from the actual ioremapping.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> ---
>
> Changes since v1:
> - None
>
>   drivers/of/platform.c   |  1 +
>   drivers/soc/qcom/smem.c | 57 ++++++++++++++++++++++++++++-------------
>   2 files changed, 40 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 32d5ff8df747..07813fb1ef37 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -505,6 +505,7 @@ EXPORT_SYMBOL_GPL(of_platform_default_populate);
>   static const struct of_device_id reserved_mem_matches[] = {
>   	{ .compatible = "qcom,rmtfs-mem" },
>   	{ .compatible = "qcom,cmd-db" },
> +	{ .compatible = "qcom,smem" },
>   	{ .compatible = "ramoops" },
>   	{ .compatible = "nvmem-rmem" },
>   	{}
> diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
> index 4fb5aeeb0843..c7e519bfdc8a 100644
> --- a/drivers/soc/qcom/smem.c
> +++ b/drivers/soc/qcom/smem.c
> @@ -9,6 +9,7 @@
>   #include <linux/module.h>
>   #include <linux/of.h>
>   #include <linux/of_address.h>
> +#include <linux/of_reserved_mem.h>
>   #include <linux/platform_device.h>
>   #include <linux/sizes.h>
>   #include <linux/slab.h>
> @@ -240,7 +241,7 @@ static const u8 SMEM_INFO_MAGIC[] = { 0x53, 0x49, 0x49, 0x49 }; /* SIII */
>    * @size:	size of the memory region
>    */
>   struct smem_region {
> -	u32 aux_base;
> +	phys_addr_t aux_base;
>   	void __iomem *virt_base;
>   	size_t size;
>   };
> @@ -499,7 +500,7 @@ static void *qcom_smem_get_global(struct qcom_smem *smem,
>   	for (i = 0; i < smem->num_regions; i++) {
>   		region = &smem->regions[i];
>   
> -		if (region->aux_base == aux_base || !aux_base) {
> +		if ((u32)region->aux_base == aux_base || !aux_base) {
>   			if (size != NULL)
>   				*size = le32_to_cpu(entry->size);
>   			return region->virt_base + le32_to_cpu(entry->offset);
> @@ -664,7 +665,7 @@ phys_addr_t qcom_smem_virt_to_phys(void *p)
>   		if (p < region->virt_base + region->size) {
>   			u64 offset = p - region->virt_base;
>   
> -			return (phys_addr_t)region->aux_base + offset;
> +			return region->aux_base + offset;
>   		}
>   	}
>   
> @@ -863,12 +864,12 @@ qcom_smem_enumerate_partitions(struct qcom_smem *smem, u16 local_host)
>   	return 0;
>   }
>   
> -static int qcom_smem_map_memory(struct qcom_smem *smem, struct device *dev,
> -				const char *name, int i)
> +static int qcom_smem_resolve_mem(struct qcom_smem *smem, const char *name,
> +				 struct smem_region *region)
>   {
> +	struct device *dev = smem->dev;
>   	struct device_node *np;
>   	struct resource r;
> -	resource_size_t size;
>   	int ret;
>   
>   	np = of_parse_phandle(dev->of_node, name, 0);
> @@ -881,13 +882,9 @@ static int qcom_smem_map_memory(struct qcom_smem *smem, struct device *dev,
>   	of_node_put(np);
>   	if (ret)
>   		return ret;
> -	size = resource_size(&r);
>   
> -	smem->regions[i].virt_base = devm_ioremap_wc(dev, r.start, size);
> -	if (!smem->regions[i].virt_base)
> -		return -ENOMEM;
> -	smem->regions[i].aux_base = (u32)r.start;
> -	smem->regions[i].size = size;
> +	region->aux_base = r.start;
> +	region->size = resource_size(&r);
>   
>   	return 0;
>   }
> @@ -895,12 +892,14 @@ static int qcom_smem_map_memory(struct qcom_smem *smem, struct device *dev,
>   static int qcom_smem_probe(struct platform_device *pdev)
>   {
>   	struct smem_header *header;
> +	struct reserved_mem *rmem;
>   	struct qcom_smem *smem;
>   	size_t array_size;
>   	int num_regions;
>   	int hwlock_id;
>   	u32 version;
>   	int ret;
> +	int i;

Just a nitpicking, the index can be unsigned.

>   
>   	num_regions = 1;
>   	if (of_find_property(pdev->dev.of_node, "qcom,rpm-msg-ram", NULL))
> @@ -914,13 +913,35 @@ static int qcom_smem_probe(struct platform_device *pdev)
>   	smem->dev = &pdev->dev;
>   	smem->num_regions = num_regions;
>   
> -	ret = qcom_smem_map_memory(smem, &pdev->dev, "memory-region", 0);
> -	if (ret)
> -		return ret;
> +	rmem = of_reserved_mem_lookup(pdev->dev.of_node);
> +	if (rmem) {
> +		smem->regions[0].aux_base = rmem->base;
> +		smem->regions[0].size = rmem->size;
> +	} else {
> +		/*
> +		 * Fall back to the memory-region reference, if we're not a
> +		 * reserved-memory node.
> +		 */
> +		ret = qcom_smem_resolve_mem(smem, "memory-region", &smem->regions[0]);
> +		if (ret)
> +			return ret;
> +	}
>   
> -	if (num_regions > 1 && (ret = qcom_smem_map_memory(smem, &pdev->dev,
> -					"qcom,rpm-msg-ram", 1)))
> -		return ret;
> +	if (num_regions > 1) {
> +		ret = qcom_smem_resolve_mem(smem, "qcom,rpm-msg-ram", &smem->regions[1]);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	for (i = 0; i < num_regions; i++) {
> +		smem->regions[i].virt_base = devm_ioremap_wc(&pdev->dev,
> +							     smem->regions[i].aux_base,
> +							     smem->regions[i].size);
> +		if (!smem->regions[i].virt_base) {
> +			dev_err(&pdev->dev, "failed to remap %pa\n", &smem->regions[i].aux_base);
> +			return -ENOMEM;
> +		}
> +	}
>   
>   	header = smem->regions[0].virt_base;
>   	if (le32_to_cpu(header->initialized) != 1 ||

--
Best wishes,
Vladimir