linux-kernel - Re: [PATCH v16 5/9] PCI/DPC: Cache DPC capabilities in pci_init

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Date:   Tue, 3 Mar 2020 18:47:05 -0600
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     sathyanarayanan.kuppuswamy@...ux.intel.com
Cc:     linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        ashok.raj@...el.com
Subject: Re: [PATCH v16 5/9] PCI/DPC: Cache DPC capabilities in
 pci_init_capabilities()

On Thu, Feb 27, 2020 at 04:59:47PM -0800, sathyanarayanan.kuppuswamy@...ux.intel.com wrote:
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
> 
> Since we need to re-use DPC error handling routines in Error Disconnect
> Recover (EDR) driver, move the initalization and caching of DPC
> capabilities to pci_init_capabilities().
> 
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
> ---
>  drivers/pci/pci.h      |  2 ++
>  drivers/pci/pcie/dpc.c | 32 ++++++++++++++++++++------------
>  2 files changed, 22 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index c2c35f152cde..e57e78b619f8 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -448,9 +448,11 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info);
>  #ifdef CONFIG_PCIE_DPC
>  void pci_save_dpc_state(struct pci_dev *dev);
>  void pci_restore_dpc_state(struct pci_dev *dev);
> +void pci_dpc_init(struct pci_dev *pdev);
>  #else
>  static inline void pci_save_dpc_state(struct pci_dev *dev) {}
>  static inline void pci_restore_dpc_state(struct pci_dev *dev) {}
> +static inline void pci_dpc_init(struct pci_dev *pdev) {}
>  #endif
>  
>  #ifdef CONFIG_PCI_ATS
> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
> index 114358d62ddf..57e7f94b98cf 100644
> --- a/drivers/pci/pcie/dpc.c
> +++ b/drivers/pci/pcie/dpc.c
> @@ -249,6 +249,26 @@ static irqreturn_t dpc_irq(int irq, void *context)
>  	return IRQ_HANDLED;
>  }
>  
> +void pci_dpc_init(struct pci_dev *pdev)
> +{

I think you forgot to call this?

> +	u16 cap;
> +
> +	pdev->dpc_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC);
> +	if (!pdev->dpc_cap)
> +		return;
> +
> +	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap);
> +	pdev->dpc_rp_extensions = (cap & PCI_EXP_DPC_CAP_RP_EXT) ? 1 : 0;
> +	if (pdev->dpc_rp_extensions) {
> +		pdev->dpc_rp_log_size = (cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
> +		if (pdev->dpc_rp_log_size < 4 || pdev->dpc_rp_log_size > 9) {
> +			pci_err(pdev, "RP PIO log size %u is invalid\n",
> +				pdev->dpc_rp_log_size);
> +			pdev->dpc_rp_log_size = 0;
> +		}
> +	}
> +}
> +
>  #define FLAG(x, y) (((x) & (y)) ? '+' : '-')
>  static int dpc_probe(struct pcie_device *dev)
>  {
> @@ -260,8 +280,6 @@ static int dpc_probe(struct pcie_device *dev)
>  	if (pcie_aer_get_firmware_first(pdev) && !pcie_ports_dpc_native)
>  		return -ENOTSUPP;
>  
> -	pdev->dpc_cap = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC);
> -
>  	status = devm_request_threaded_irq(device, dev->irq, dpc_irq,
>  					   dpc_handler, IRQF_SHARED,
>  					   "pcie-dpc", pdev);
> @@ -274,16 +292,6 @@ static int dpc_probe(struct pcie_device *dev)
>  	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CAP, &cap);
>  	pci_read_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, &ctl);
>  
> -	pdev->dpc_rp_extensions = (cap & PCI_EXP_DPC_CAP_RP_EXT) ? 1 : 0;
> -	if (pdev->dpc_rp_extensions) {
> -		pdev->dpc_rp_log_size = (cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
> -		if (pdev->dpc_rp_log_size < 4 || pdev->dpc_rp_log_size > 9) {
> -			pci_err(pdev, "RP PIO log size %u is invalid\n",
> -				pdev->dpc_rp_log_size);
> -			pdev->dpc_rp_log_size = 0;
> -		}
> -	}
> -
>  	ctl = (ctl & 0xfff4) | PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN;
>  	pci_write_config_word(pdev, pdev->dpc_cap + PCI_EXP_DPC_CTL, ctl);
>  
> -- 
> 2.21.0
>