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Date:   Thu, 10 Aug 2023 18:17:34 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     LeoLiu-oc <LeoLiu-oc@zhaoxin.com>
Cc:     lenb@kernel.org, james.morse@arm.com, tony.luck@intel.com,
        bp@alien8.de, bhelgaas@google.com, robert.moore@intel.com,
        linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-pci@vger.kernel.org, acpica-devel@lists.linuxfoundation.org
Subject: Re: [PATCH v3 1/5] ACPI/APEI: Add apei_hest_parse_aer()
Message-ID: <20230810231734.GA41600@bhelgaas>
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In-Reply-To: <20230704120505.1322152-1-LeoLiu-oc@zhaoxin.com>
Precedence: bulk

On Tue, Jul 04, 2023 at 08:05:05PM +0800, LeoLiu-oc wrote:
> From: leoliu-oc <leoliu-oc@zhaoxin.com>
> 
> apei_hest_parse_aer() is used to parse and extract register values
> from HEST PCIe AER structures.
> 
> Signed-off-by: leoliu-oc <leoliu-oc@zhaoxin.com>
> ---
>  drivers/acpi/apei/hest.c | 114 ++++++++++++++++++++++++++++++++++++++-
>  include/acpi/actbl1.h    |  69 ++++++++++++++++++++++++
>  include/acpi/apei.h      |   7 +++
>  3 files changed, 189 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/apei/hest.c b/drivers/acpi/apei/hest.c
> index 6aef1ee5e1bdb..fb839a5c480ee 100644
> --- a/drivers/acpi/apei/hest.c
> +++ b/drivers/acpi/apei/hest.c
> @@ -26,6 +26,7 @@
>  #include <acpi/apei.h>
>  #include <acpi/ghes.h>
>  
> +#include <linux/pci.h>

Should go in the list above along with the other <linux/...> includes.
The trend is to alphabetize the list, so I'd put it here:

   #include <linux/io.h>
  +#include <linux/pci.h>
   #include <linux/platform_device.h>

>  #include "apei-internal.h"
>  
>  #define HEST_PFX "HEST: "
> @@ -86,7 +87,50 @@ static int hest_esrc_len(struct acpi_hest_header *hest_hdr)
>  	return len;
>  };
>  
> -typedef int (*apei_hest_func_t)(struct acpi_hest_header *hest_hdr, void *data);

I think moving this typedef to include/acpi/apei.h should happen in
the patch where it is needed.  I *think* that's the "Remove static
from apei_hest_parse()" patch.

> +static bool hest_source_is_pcie_aer(struct acpi_hest_header *hest_hdr)
> +{
> +	switch (hest_hdr->type) {
> +	case ACPI_HEST_TYPE_AER_ROOT_PORT:
> +	case ACPI_HEST_TYPE_AER_ENDPOINT:
> +	case ACPI_HEST_TYPE_AER_BRIDGE:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool hest_match_type(struct acpi_hest_header *hest_hdr,
> +				struct pci_dev *dev)

Align "struct pci_dev" under "struct acpi_hest_header", as is typical
(see apei-base.c, erst.c, ghes.c)

> +{
> +	u16 hest_type = hest_hdr->type;
> +	u8 pcie_type = pci_pcie_type(dev);
> +
> +	if ((hest_type == ACPI_HEST_TYPE_AER_ROOT_PORT &&
> +		pcie_type == PCI_EXP_TYPE_ROOT_PORT) ||
> +		(hest_type == ACPI_HEST_TYPE_AER_ENDPOINT &&
> +		pcie_type == PCI_EXP_TYPE_ENDPOINT) ||
> +		(hest_type == ACPI_HEST_TYPE_AER_BRIDGE &&
> +		(pcie_type == PCI_EXP_TYPE_PCI_BRIDGE || pcie_type == PCI_EXP_TYPE_PCIE_BRIDGE)))
> +		return true;
> +	return false;
> +}
> +
> +static bool hest_match_pci_devfn(struct acpi_hest_aer_common *p,
> +		struct pci_dev *pci)

Align parameters.

> +{
> +	return	ACPI_HEST_SEGMENT(p->bus) == pci_domain_nr(pci->bus) &&
> +			ACPI_HEST_BUS(p->bus)     == pci->bus->number &&
> +			p->device                 == PCI_SLOT(pci->devfn) &&
> +			p->function               == PCI_FUNC(pci->devfn);

Remove double space before ACPI_HEST_SEGMENT().  Align the other lines
under ACPI_HEST_SEGMENT() and don't bother indenting the
pci->bus->number, PCI_SLOT, PCI_FUNC, since they don't line up anyway,
i.e.,

  return ACPI_HEST_SEGMENT(p->bus) == pci_domain_nr(pci->bus) &&
         ACPI_HEST_BUS(p->bus) == pci->bus->number &&
	 p->device == PCI_SLOT(pci->devfn) &&
         p->function == PCI_FUNC(pci->devfn);

The only allowable variable names for a pci_dev pointer are "dev" or
"pdev" :)  In this context, I think "dev" is fine (as you used above
for hest_match_type()).

> +}
> +
> +static bool hest_match_pci(struct acpi_hest_header *hest_hdr,
> +		struct acpi_hest_aer_common *p, struct pci_dev *pci)
> +{
> +	if (hest_match_type(hest_hdr, pci))
> +		return hest_match_pci_devfn(p, pci);
> +	return false;
> +}
>  
>  static int apei_hest_parse(apei_hest_func_t func, void *data)
>  {
> @@ -124,6 +168,74 @@ static int apei_hest_parse(apei_hest_func_t func, void *data)
>  	return 0;
>  }
>  
> +/*
> + * apei_hest_parse_aer - Find the AER structure in the HEST and
> + * match it with the PCIe device.
> + *
> + * @hest_hdr: To save the ACPI AER error source in HEST
> + *
> + * Return 1 if the PCIe dev matched with the ACPI AER error source in
> + * HEST, else return 0.
> + */
> +int apei_hest_parse_aer(struct acpi_hest_header *hest_hdr, void *data)

Follow the naming pattern of all the other parse functions:

  hest_parse_ghes_count
  hest_parse_ghes
  hest_parse_cmc

E.g., "hest_parse_pcie_aer" or "hest_parse_aer".

> +{
> +	struct acpi_hest_parse_aer_info *info = data;

> +	struct acpi_hest_aer_endpoint *acpi_hest_aer_endpoint = NULL;
> +	struct acpi_hest_aer_root_port *acpi_hest_aer_root_port = NULL;
> +	struct acpi_hest_aer_for_bridge *acpi_hest_aer_for_bridge = NULL;

Unnecessary initializations since you always set these below before
using them.  But maybe there's a way to do this without these pointers
(see below).

> +	if (!hest_source_is_pcie_aer(hest_hdr))
> +		return 0;
> +
> +	switch (hest_hdr->type) {
> +	case ACPI_HEST_TYPE_AER_ROOT_PORT:
> +		acpi_hest_aer_root_port = (struct acpi_hest_aer_root_port *)(hest_hdr + 1);
> +		if (acpi_hest_aer_root_port->flags & ACPI_HEST_GLOBAL) {
> +			if (hest_match_type(hest_hdr, info->pci_dev)) {
> +				info->acpi_hest_aer_root_port = acpi_hest_aer_root_port;
> +				info->hest_matched_with_dev = 1;
> +			}
> +		} else if (hest_match_pci(hest_hdr,
> +					(struct acpi_hest_aer_common *)acpi_hest_aer_root_port,
> +					info->pci_dev)) {
> +			info->acpi_hest_aer_root_port = acpi_hest_aer_root_port;
> +			info->hest_matched_with_dev = 1;
> +		}
> +		break;

Could this be refactored along the lines of this?

  static bool matches(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 =
        (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;
    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_BRIDGE &&
          pcie_type != PCI_EXP_TYPE_PCIE_BRIDGE)
        return false;
      break;
    default:
      return false;
    }

    if (common->flags & ACPI_HEST_GLOBAL)
      return true;

    if (hest_match_pci_devfn(common, dev))
      return true;

    return false;
  }

  int apei_hest_parse_aer(...)
  {
    if (!matches(hest_hdr, info->pci_dev))
      return 0;

    switch (hest_type) {
    case ACPI_HEST_TYPE_AER_ROOT_PORT:
      info->acpi_hest_aer_root_port =
          (struct acpi_hest_aer_root_port *)(hest_hdr + 1);
      info->hest_matched_with_dev = 1;
      return 1;
    case ACPI_HEST_TYPE_AER_ENDPOINT:
      ...
    }

    return 0;
  }

> +	case ACPI_HEST_TYPE_AER_ENDPOINT:
> +		acpi_hest_aer_endpoint = (struct acpi_hest_aer_endpoint *)(hest_hdr + 1);
> +		if (acpi_hest_aer_endpoint->flags & ACPI_HEST_GLOBAL) {
> +			if (hest_match_type(hest_hdr, info->pci_dev)) {
> +				info->acpi_hest_aer_endpoint = acpi_hest_aer_endpoint;
> +				info->hest_matched_with_dev = 1;
> +			}
> +		} else if (hest_match_pci(hest_hdr,
> +					(struct acpi_hest_aer_common *)acpi_hest_aer_endpoint,
> +					info->pci_dev)) {
> +				info->acpi_hest_aer_endpoint = acpi_hest_aer_endpoint;
> +				info->hest_matched_with_dev = 1;
> +		}
> +		break;
> +	case ACPI_HEST_TYPE_AER_BRIDGE:
> +		acpi_hest_aer_for_bridge = (struct acpi_hest_aer_for_bridge *)(hest_hdr + 1);
> +		if (acpi_hest_aer_for_bridge->flags & ACPI_HEST_GLOBAL) {
> +			if (hest_match_type(hest_hdr, info->pci_dev)) {
> +				info->acpi_hest_aer_for_bridge = acpi_hest_aer_for_bridge;
> +				info->hest_matched_with_dev = 1;
> +			}
> +		} else if (hest_match_pci(hest_hdr,
> +					(struct acpi_hest_aer_common *)acpi_hest_aer_for_bridge,
> +					info->pci_dev)) {
> +				info->acpi_hest_aer_for_bridge = acpi_hest_aer_for_bridge;
> +				info->hest_matched_with_dev = 1;
> +			}
> +		break;
> +	default:
> +		break;
> +	}
> +	return info->hest_matched_with_dev;
> +}
> +
>  /*
>   * Check if firmware advertises firmware first mode. We need FF bit to be set
>   * along with a set of MC banks which work in FF mode.
> diff --git a/include/acpi/actbl1.h b/include/acpi/actbl1.h
> index 58b0490a2ad12..31abe06c6e792 100644
> --- a/include/acpi/actbl1.h
> +++ b/include/acpi/actbl1.h
> @@ -1583,6 +1583,75 @@ struct acpi_hest_aer_bridge {
>  	u32 advanced_capabilities2;
>  };
>  
> +struct acpi_hest_parse_aer_info {
> +	struct pci_dev *pci_dev;
> +	int hest_matched_with_dev;
> +	struct acpi_hest_aer_endpoint *acpi_hest_aer_endpoint;
> +	struct acpi_hest_aer_root_port *acpi_hest_aer_root_port;
> +	struct acpi_hest_aer_for_bridge *acpi_hest_aer_for_bridge;
> +};
> +
> +/* HEST Sub-structure for PCIe Root Port Structure (6) */
> +
> +struct acpi_hest_aer_root_port {

How are these different from the existing acpi_hest_aer_root,
acpi_hest_aer, and acpi_hest_aer_bridge?

I see that the existing acpi_hest_aer_root includes a struct
acpi_hest_header and the new acpi_hest_aer_root_port does not, but
that doesn't seem like enough reason to duplicate all the rest of the
structure.

Sorry if you've answered this before.  If we really need both
acpi_hest_aer_root and acpi_hest_aer_root_port, we should put a hint
about the reason in the commit log and maybe even in a code comment
here.

> +	u16 reserved1;
> +	u8 flags;
> +	u8 enabled;
> +	u32 records_to_preallocate;
> +	u32 max_sections_per_record;
> +	u32 bus;
> +	u16 device;
> +	u16 function;
> +	u16 device_control;
> +	u16 reserved2;
> +	u32 uncorrectable_mask;
> +	u32 uncorrectable_severity;
> +	u32 correctable_mask;
> +	u32 advanced_capabilities;
> +	u32 root_error_command;
> +};

> +/* HEST Sub-structure for PCIe/PCI-X Bridge Structure (8) */
> +
> +struct acpi_hest_aer_for_bridge {

If this struct is needed, s/for_// (the other structs don't include
"for_" and there's no need here).