[v4,1/3] ACPI/APEI: Add hest_parse_pcie_aer()

From: LeoLiuoc <LeoLiu-oc@zhaoxin.com>

The purpose of the function apei_hest_parse_aer() is used to parse and
extract register value from HEST PCIe AER structures. This applies to
all hardware platforms that has a PCI Express AER structure in HEST.

Signed-off-by: LeoLiuoc <LeoLiu-oc@zhaoxin.com>
---
 drivers/acpi/apei/hest.c | 77 ++++++++++++++++++++++++++++++++++++++--
 include/acpi/apei.h      | 17 +++++++++
 2 files changed, 92 insertions(+), 2 deletions(-)

On Thu, Dec 05, 2024 at 07:40:46PM +0800, LeoLiu-oc wrote:
> From: LeoLiuoc <LeoLiu-oc@zhaoxin.com>
> 
> The purpose of the function apei_hest_parse_aer() is used to parse and
> extract register value from HEST PCIe AER structures. This applies to
> all hardware platforms that has a PCI Express AER structure in HEST.
> 
> Signed-off-by: LeoLiuoc <LeoLiu-oc@zhaoxin.com>
> ---
>  drivers/acpi/apei/hest.c | 77 ++++++++++++++++++++++++++++++++++++++--
>  include/acpi/apei.h      | 17 +++++++++
>  2 files changed, 92 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/acpi/apei/hest.c b/drivers/acpi/apei/hest.c
> index 20d757687e3d..13075f5aea25 100644
> --- a/drivers/acpi/apei/hest.c
> +++ b/drivers/acpi/apei/hest.c
> @@ -22,6 +22,7 @@
>  #include <linux/kdebug.h>
>  #include <linux/highmem.h>
>  #include <linux/io.h>
> +#include <linux/pci.h>
>  #include <linux/platform_device.h>
>  #include <acpi/apei.h>
>  #include <acpi/ghes.h>
> @@ -132,9 +133,81 @@ static bool is_ghes_assist_struct(struct acpi_hest_header *hest_hdr)
>  	return false;
>  }
>  
> -typedef int (*apei_hest_func_t)(struct acpi_hest_header *hest_hdr, void *data);
> +#ifdef CONFIG_ACPI_APEI

Why is this needed? The entire hest.c file is only built if
CONFIG_ACPI_APEI is enabled.

> +static bool hest_match_pci_devfn(struct acpi_hest_aer_common *p,
> +				 struct pci_dev *dev)
> +{
> +	return ACPI_HEST_SEGMENT(p->bus) == pci_domain_nr(dev->bus) &&
> +	       ACPI_HEST_BUS(p->bus) == dev->bus->number &&
> +	       p->device == PCI_SLOT(dev->devfn) &&
> +	       p->function == PCI_FUNC(dev->devfn);

It may be nice to align all these lines on the "==".

> +}
> +
> +static bool hest_source_is_pcie_aer(struct acpi_hest_header *hest_hdr,
> +				    struct pci_dev *dev)
> +{
> +	u16 hest_type = hest_hdr->type;
> +	u8 pcie_type = pci_pcie_type(dev);
> +	struct acpi_hest_aer_common *common;
> +
> +	common = (struct acpi_hest_aer_common *)(hest_hdr + 1);
> +
> +	switch (hest_type) {
> +	case ACPI_HEST_TYPE_AER_ROOT_PORT:
> +		if (pcie_type != PCI_EXP_TYPE_ROOT_PORT)
> +			return false;
> +	break;

The breaks should be indented to the "if". Same for the rest of the
file.

> +	case ACPI_HEST_TYPE_AER_ENDPOINT:
> +		if (pcie_type != PCI_EXP_TYPE_ENDPOINT)
> +			return false;
> +	break;
> +	case ACPI_HEST_TYPE_AER_BRIDGE:
> +		if (pcie_type != PCI_EXP_TYPE_PCI_BRIDGE &&
> +		    pcie_type != PCI_EXP_TYPE_PCIE_BRIDGE)
> +			return false;
> +	break;
> +	default:
> +		return false;
> +	break;
> +	}
> +
> +	if (common->flags & ACPI_HEST_GLOBAL)
> +		return true;
> +
> +	if (hest_match_pci_devfn(common, dev))
> +		return true;
> +
> +	return false;
> +}
> +
> +int hest_parse_pcie_aer(struct acpi_hest_header *hest_hdr, void *data)
> +{
> +	struct hest_parse_aer_info *info = data;
> +
> +	if (!hest_source_is_pcie_aer(hest_hdr, info->pci_dev))
> +		return 0;
> +
> +	switch (hest_hdr->type) {
> +	case ACPI_HEST_TYPE_AER_ROOT_PORT:
> +		info->hest_aer_root_port = (struct acpi_hest_aer_root *)hest_hdr;
> +		return 1;
> +	break;
> +	case ACPI_HEST_TYPE_AER_ENDPOINT:
> +		info->hest_aer_endpoint = (struct acpi_hest_aer *)hest_hdr;
> +		return 1;
> +	break;
> +	case ACPI_HEST_TYPE_AER_BRIDGE:
> +		info->hest_aer_bridge = (struct acpi_hest_aer_bridge *)hest_hdr;
> +		return 1;
> +	break;
> +	default:
> +		return 0;
> +	break;
> +	}
> +}
> +#endif
>  
> -static int apei_hest_parse(apei_hest_func_t func, void *data)
> +int apei_hest_parse(apei_hest_func_t func, void *data)
>  {
>  	struct acpi_hest_header *hest_hdr;
>  	int i, rc, len;
> diff --git a/include/acpi/apei.h b/include/acpi/apei.h
> index dc60f7db5524..82d3cdf53e22 100644
> --- a/include/acpi/apei.h
> +++ b/include/acpi/apei.h
> @@ -23,6 +23,15 @@ enum hest_status {
>  	HEST_NOT_FOUND,
>  };
>  
> +#ifdef CONFIG_ACPI_APEI
> +struct hest_parse_aer_info {
> +	struct pci_dev *pci_dev;
> +	struct acpi_hest_aer *hest_aer_endpoint;
> +	struct acpi_hest_aer_root *hest_aer_root_port;
> +	struct acpi_hest_aer_bridge *hest_aer_bridge;

These three pointers are mutually exclusive. Can you save just one
pointer and then cast it when checking the "port_type" in patch 3?

> +};
> +#endif

I think the #ifdef is not needed, because this is not declaring an
instance of the struct.

> +
>  extern int hest_disable;
>  extern int erst_disable;
>  #ifdef CONFIG_ACPI_APEI_GHES
> @@ -33,10 +42,18 @@ void __init acpi_ghes_init(void);
>  static inline void acpi_ghes_init(void) { }
>  #endif
>  
> +typedef int (*apei_hest_func_t)(struct acpi_hest_header *hest_hdr, void *data);
> +int apei_hest_parse(apei_hest_func_t func, void *data);
> +

Minor nit: this could be done as a separate patch.

Patch 1: Move apei_hest_parse() to apei.h
Patch 2: Add new hest_parse_pcie_aer()

>  #ifdef CONFIG_ACPI_APEI
>  void __init acpi_hest_init(void);
> +int hest_parse_pcie_aer(struct acpi_hest_header *hest_hdr, void *data);
>  #else
>  static inline void acpi_hest_init(void) { }
> +static inline int hest_parse_pcie_aer(struct acpi_hest_header *hest_hdr, void *data)
> +{
> +	return 0;
> +}
>  #endif
>  
>  int erst_write(const struct cper_record_header *record);
> -- 

Thanks,
Yazen