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SubjectRe: [PATCH 1/4] PCI: dwc: Add new feature to skip core initialization
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On 11/27/2019 1:44 PM, Kishon Vijay Abraham I wrote:
> Hi,
>
> On 13/11/19 2:38 PM, Vidya Sagar wrote:
>> Add a new feature 'skip_core_init' that can be set by platform drivers
>> of devices that do not have their core registers available until reference
>> clock from host is available (Ex:- Tegra194) to indicate DesignWare
>> endpoint mode sub-system to not perform core registers initialization.
>> Existing dw_pcie_ep_init() is refactored and all the code that touches
>> registers is extracted to form a new API dw_pcie_ep_init_complete() that
>> can be called later by platform drivers setting 'skip_core_init' to '1'.
>>
>> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
>> ---
>> .../pci/controller/dwc/pcie-designware-ep.c | 72 +++++++++++--------
>> drivers/pci/controller/dwc/pcie-designware.h | 6 ++
>> include/linux/pci-epc.h | 1 +
>> 3 files changed, 51 insertions(+), 28 deletions(-)
>>
>> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
>> index 3dd2e2697294..06f4379be8a3 100644
>> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
>> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
>> @@ -492,19 +492,53 @@ static unsigned int dw_pcie_ep_find_ext_capability(struct dw_pcie *pci, int cap)
>> return 0;
>> }
>>
>> -int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>> +int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
>> {
>> + struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>> + unsigned int offset;
>> + unsigned int nbars;
>> + u8 hdr_type;
>> + u32 reg;
>> int i;
>> +
>> + hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE);
>> + if (hdr_type != PCI_HEADER_TYPE_NORMAL) {
>> + dev_err(pci->dev,
>> + "PCIe controller is not set to EP mode (hdr_type:0x%x)!\n",
>> + hdr_type);
>> + return -EIO;
>> + }
>> +
>> + ep->msi_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
>> +
>> + ep->msix_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSIX);
>> +
>> + offset = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_REBAR);
>> + if (offset) {
>> + reg = dw_pcie_readl_dbi(pci, offset + PCI_REBAR_CTRL);
>> + nbars = (reg & PCI_REBAR_CTRL_NBAR_MASK) >>
>> + PCI_REBAR_CTRL_NBAR_SHIFT;
>> +
>> + dw_pcie_dbi_ro_wr_en(pci);
>> + for (i = 0; i < nbars; i++, offset += PCI_REBAR_CTRL)
>> + dw_pcie_writel_dbi(pci, offset + PCI_REBAR_CAP, 0x0);
>> + dw_pcie_dbi_ro_wr_dis(pci);
>> + }
>> +
>> + dw_pcie_setup(pci);
>> +
>> + return 0;
>> +}
>> +
>> +int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>> +{
>> int ret;
>> - u32 reg;
>> void *addr;
>> - u8 hdr_type;
>> - unsigned int nbars;
>> - unsigned int offset;
>> struct pci_epc *epc;
>> struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>> struct device *dev = pci->dev;
>> struct device_node *np = dev->of_node;
>> + const struct pci_epc_features *epc_features;
>>
>> if (!pci->dbi_base || !pci->dbi_base2) {
>> dev_err(dev, "dbi_base/dbi_base2 is not populated\n");
>> @@ -563,13 +597,6 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>> if (ep->ops->ep_init)
>> ep->ops->ep_init(ep);
>>
>> - hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE);
>> - if (hdr_type != PCI_HEADER_TYPE_NORMAL) {
>> - dev_err(pci->dev, "PCIe controller is not set to EP mode (hdr_type:0x%x)!\n",
>> - hdr_type);
>> - return -EIO;
>> - }
>> -
>> ret = of_property_read_u8(np, "max-functions", &epc->max_functions);
>> if (ret < 0)
>> epc->max_functions = 1;
>> @@ -587,23 +614,12 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>> dev_err(dev, "Failed to reserve memory for MSI/MSI-X\n");
>> return -ENOMEM;
>> }
>> - ep->msi_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSI);
>>
>> - ep->msix_cap = dw_pcie_find_capability(pci, PCI_CAP_ID_MSIX);
>> -
>> - offset = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_REBAR);
>> - if (offset) {
>> - reg = dw_pcie_readl_dbi(pci, offset + PCI_REBAR_CTRL);
>> - nbars = (reg & PCI_REBAR_CTRL_NBAR_MASK) >>
>> - PCI_REBAR_CTRL_NBAR_SHIFT;
>> -
>> - dw_pcie_dbi_ro_wr_en(pci);
>> - for (i = 0; i < nbars; i++, offset += PCI_REBAR_CTRL)
>> - dw_pcie_writel_dbi(pci, offset + PCI_REBAR_CAP, 0x0);
>> - dw_pcie_dbi_ro_wr_dis(pci);
>> + if (ep->ops->get_features) {
>> + epc_features = ep->ops->get_features(ep);
>> + if (epc_features->skip_core_init)
>> + return 0;
>> }
>>
>> - dw_pcie_setup(pci);
>> -
>> - return 0;
>> + return dw_pcie_ep_init_complete(ep);
>> }
>> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
>> index 5accdd6bc388..340783e9032e 100644
>> --- a/drivers/pci/controller/dwc/pcie-designware.h
>> +++ b/drivers/pci/controller/dwc/pcie-designware.h
>> @@ -399,6 +399,7 @@ static inline int dw_pcie_allocate_domains(struct pcie_port *pp)
>> #ifdef CONFIG_PCIE_DW_EP
>> void dw_pcie_ep_linkup(struct dw_pcie_ep *ep);
>> int dw_pcie_ep_init(struct dw_pcie_ep *ep);
>> +int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep);
>> void dw_pcie_ep_exit(struct dw_pcie_ep *ep);
>> int dw_pcie_ep_raise_legacy_irq(struct dw_pcie_ep *ep, u8 func_no);
>> int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
>> @@ -416,6 +417,11 @@ static inline int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>> return 0;
>> }
>>
>> +static inline int dw_pcie_ep_init_complete(struct dw_pcie_ep *ep)
>> +{
>> + return 0;
>> +}
>> +
>> static inline void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
>> {
>> }
>> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
>> index 36644ccd32ac..241e6a6f39fb 100644
>> --- a/include/linux/pci-epc.h
>> +++ b/include/linux/pci-epc.h
>> @@ -121,6 +121,7 @@ struct pci_epc_features {
>> u8 bar_fixed_64bit;
>> u64 bar_fixed_size[PCI_STD_NUM_BARS];
>> size_t align;
>> + bool skip_core_init;
>
> This looks more like a designware specific change. Why is it added to the core
> pci_epc_features?
Although the changes are done in DesignWare core (as Tegra194 uses DesignWare IP),
core not being available for programming before REFCLK from host is available, seemed
like a very generic case to me, so I added this as part of core features it self.

Thanks,
Vidya Sagar
>
> Thanks
> Kishon
>

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