Re: [RFC PATCH v2 01/32] PCI: add pcie_flags_reg into struct pci_devto cache PCIe capabilities register

From: Yijing Wang
Date: Thu Jul 26 2012 - 09:47:28 EST


ä 2012-07-25 23:12, Don Dutile åé:
> resending since i did a reply vs reply-all last time...
>
> On 07/24/2012 12:31 PM, Jiang Liu wrote:
>> From: Yijing Wang<wangyijing@xxxxxxxxxx>
>>
>> From: Yijing Wang<wangyijing@xxxxxxxxxx>
>>
>> Since PCI Express Capabilities Register is read only, cache its value
>> into struct pci_dev to avoid repeatedly calling pci_read_config_*().
>>
>> Signed-off-by: Yijing Wang<wangyijing@xxxxxxxxxx>
>> Signed-off-by: Jiang Liu<liuj97@xxxxxxxxx>
>> ---
>> drivers/pci/probe.c | 1 +
>> include/linux/pci.h | 10 ++++++++++
>> 2 files changed, 11 insertions(+)
>>
>> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
>> index 6c143b4..6fd58df 100644
>> --- a/drivers/pci/probe.c
>> +++ b/drivers/pci/probe.c
>> @@ -929,6 +929,7 @@ void set_pcie_port_type(struct pci_dev *pdev)
>> pdev->is_pcie = 1;
>> pdev->pcie_cap = pos;
>> pci_read_config_word(pdev, pos + PCI_EXP_FLAGS,&reg16);
>> + pdev->pcie_flags_reg = reg16;
>> pdev->pcie_type = (reg16& PCI_EXP_FLAGS_TYPE)>> 4;
> So, given the patch below, shouldn't the above line be ?
> pdev->pcie_type = pci_pcie_type(pdev);
>
Hi,Don Dutile,thanks for your comments very much!
> Missed part of patch ?
pdev->pcie_type was removed in the later patch([RFC PATCH v2 03/32] PCI: remove unused field pcie_type from struct pci_dev),
so I leave it here unmodified.
But your suggestion let this patch become more reasonable.
Thanks.
>
>> pci_read_config_word(pdev, pos + PCI_EXP_DEVCAP,&reg16);
>> pdev->pcie_mpss = reg16& PCI_EXP_DEVCAP_PAYLOAD;
>> diff --git a/include/linux/pci.h b/include/linux/pci.h
>> index 5faa831..95662b2 100644
>> --- a/include/linux/pci.h
>> +++ b/include/linux/pci.h
>> @@ -258,6 +258,7 @@ struct pci_dev {
>> u8 pcie_mpss:3; /* PCI-E Max Payload Size Supported */
>> u8 rom_base_reg; /* which config register controls the ROM */
>> u8 pin; /* which interrupt pin this device uses */
>> + u16 pcie_flags_reg; /* cached PCI-E Capabilities Register */
>>
>> struct pci_driver *driver; /* which driver has allocated this device */
>> u64 dma_mask; /* Mask of the bits of bus address this
>> @@ -1650,6 +1651,15 @@ static inline bool pci_is_pcie(struct pci_dev *dev)
>> return !!pci_pcie_cap(dev);
>> }
>>
>> +/**
>> + * pci_pcie_type - get the PCIe device/port type
>> + * @dev: PCI device
>> + */
>> +static inline int pci_pcie_type(const struct pci_dev *dev)
>> +{
>> + return (dev->pcie_flags_reg& PCI_EXP_FLAGS_TYPE)>> 4;
>> +}
>> +
>> void pci_request_acs(void);
>> bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags);
>> bool pci_acs_path_enabled(struct pci_dev *start,
>
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