Re: [PATCH V4 05/16] PCI: dwc: Move config space capability search API

Vidya Sagar
2019-04-24T03:12:24Z

On 4/24/2019 2:02 AM, Bjorn Helgaas wrote:
> On Tue, Apr 23, 2019 at 01:57:19PM +0530, Vidya Sagar wrote:
>> Move PCIe config space capability search API to common DesignWare file
>> as this can be used by both host and ep mode codes.
>>
>> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
>> Acked-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
>> ---
>> Changes from [v3]:
>> * Rebased to linux-next top of the tree
>>
>> Changes from [v2]:
>> * None
>>
>> Changes from [v1]:
>> * Removed dw_pcie_find_next_ext_capability() API from here and made a
>> separate patch for that
>>
>> drivers/pci/controller/dwc/pcie-designware.c | 33 ++++++++++++++++++++
>> drivers/pci/controller/dwc/pcie-designware.h | 2 ++
>
> You claim this is a "move", but I only see adds. Where did it move
> *from*?
These are supposed to be moved from pcie-designware-ep.c file. That was the case
with my old patches but when I rebased them onto ToT, I missed the change that
removes them from pcie-designware-ep.c file. Thanks for catching this. I'll
address it in the next patch.

>
> While you're at it, can you add a comment in the code about why we
> can't use the regular pci_find_capability() interface? It's really a
> shame to have to reimplement that.
Regular pci_find_capability() uses 'struct pci_dev *dev' pointer and can be used
only after device enumeration is done. Whereas, these APIs are used particularly
before link up and use 'struct dw_pcie *pci' pointer.

>
>> 2 files changed, 35 insertions(+)
>>
>> diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
>> index 8e0081ccf83b..6a98135244d6 100644
>> --- a/drivers/pci/controller/dwc/pcie-designware.c
>> +++ b/drivers/pci/controller/dwc/pcie-designware.c
>> @@ -20,6 +20,39 @@
>> #define PCIE_PHY_DEBUG_R1_LINK_UP (0x1 << 4)
>> #define PCIE_PHY_DEBUG_R1_LINK_IN_TRAINING (0x1 << 29)
>>
>> +static u8 __dw_pcie_find_next_cap(struct dw_pcie *pci, u8 cap_ptr,
>> + u8 cap)
>> +{
>> + u8 cap_id, next_cap_ptr;
>> + u16 reg;
>> +
>> + reg = dw_pcie_readw_dbi(pci, cap_ptr);
>> + next_cap_ptr = (reg & 0xff00) >> 8;
>> + cap_id = (reg & 0x00ff);
>> +
>> + if (!next_cap_ptr || cap_id > PCI_CAP_ID_MAX)
>> + return 0;
>> +
>> + if (cap_id == cap)
>> + return cap_ptr;
>> +
>> + return __dw_pcie_find_next_cap(pci, next_cap_ptr, cap);
>> +}
>> +
>> +u8 dw_pcie_find_capability(struct dw_pcie *pci, u8 cap)
>> +{
>> + u8 next_cap_ptr;
>> + u16 reg;
>> +
>> + reg = dw_pcie_readw_dbi(pci, PCI_CAPABILITY_LIST);
>> + next_cap_ptr = (reg & 0x00ff);
>> +
>> + if (!next_cap_ptr)
>> + return 0;
>> +
>> + return __dw_pcie_find_next_cap(pci, next_cap_ptr, cap);
>> +}
>> +
>> int dw_pcie_read(void __iomem *addr, int size, u32 *val)
>> {
>> if (!IS_ALIGNED((uintptr_t)addr, size)) {
>> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
>> index 9ee98ced1ef6..35160b4ce929 100644
>> --- a/drivers/pci/controller/dwc/pcie-designware.h
>> +++ b/drivers/pci/controller/dwc/pcie-designware.h
>> @@ -248,6 +248,8 @@ struct dw_pcie {
>> #define to_dw_pcie_from_ep(endpoint) \
>> container_of((endpoint), struct dw_pcie, ep)
>>
>> +u8 dw_pcie_find_capability(struct dw_pcie *pci, u8 cap);
>> +
>> int dw_pcie_read(void __iomem *addr, int size, u32 *val);
>> int dw_pcie_write(void __iomem *addr, int size, u32 val);
>>
>> --
>> 2.17.1
>>