Re: [PATCH RESEND v4 04/15] PCI: dwc: Add IP-core version detection procedure

Manivannan Sadhasivam
2022-08-01T13:12:34Z

On Fri, Jun 24, 2022 at 05:39:36PM +0300, Serge Semin wrote:
> Since DWC PCIe v4.70a the controller version and version type can be read
> from the PORT_LOGIC.PCIE_VERSION_OFF and PORT_LOGIC.PCIE_VERSION_TYPE_OFF
> registers respectively. Seeing the generic code has got version-dependent
> parts let's use these registers to find out the controller version. The
> detection procedure is executed for both RC and EP modes right after the
> platform-specific initialization. We can't do that earlier since the
> glue-drivers can perform the DBI-related setups there including the bus
> reference clocks activation, without which the CSRs just can't be read.
>
> Note the CSRs content is zero on the older DWC PCIe controller. In that
> case we have no choice but to rely on the platform setup.
>
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

> Reviewed-by: Rob Herring <robh@kernel.org>
>
> ---
>
> Changelog v2:
> - Move the IP-core version detection procedure call from
> dw_pcie_ep_init_complete() to dw_pcie_ep_init().
> ---
> .../pci/controller/dwc/pcie-designware-ep.c | 2 ++
> .../pci/controller/dwc/pcie-designware-host.c | 2 ++
> drivers/pci/controller/dwc/pcie-designware.c | 24 +++++++++++++++++++
> drivers/pci/controller/dwc/pcie-designware.h | 6 +++++
> 4 files changed, 34 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index 1e35542d6f72..ffbd3af6d65a 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> @@ -711,6 +711,8 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> ep->phys_base = res->start;
> ep->addr_size = resource_size(res);
>
> + dw_pcie_version_detect(pci);
> +

There is still an ongoing debate about moving all DBI accesses to
init_complete. But this is fine atm.

Thanks,
Mani

> dw_pcie_iatu_detect(pci);
>
> ep->ib_window_map = devm_kcalloc(dev,
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 95256434913f..b1437b37140f 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -405,6 +405,8 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
> }
> }
>
> + dw_pcie_version_detect(pci);
> +
> dw_pcie_iatu_detect(pci);
>
> dw_pcie_setup_rc(pp);
> diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> index f10a7d5d94e8..cbb36ccaa48b 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.c
> +++ b/drivers/pci/controller/dwc/pcie-designware.c
> @@ -16,6 +16,30 @@
> #include "../../pci.h"
> #include "pcie-designware.h"
>
> +void dw_pcie_version_detect(struct dw_pcie *pci)
> +{
> + u32 ver;
> +
> + /* The content of the CSR is zero on DWC PCIe older than v4.70a */
> + ver = dw_pcie_readl_dbi(pci, PCIE_VERSION_NUMBER);
> + if (!ver)
> + return;
> +
> + if (pci->version && pci->version != ver)
> + dev_warn(pci->dev, "Versions don't match (%08x != %08x)\n",
> + pci->version, ver);
> + else
> + pci->version = ver;
> +
> + ver = dw_pcie_readl_dbi(pci, PCIE_VERSION_TYPE);
> +
> + if (pci->type && pci->type != ver)
> + dev_warn(pci->dev, "Types don't match (%08x != %08x)\n",
> + pci->type, ver);
> + else
> + pci->type = ver;
> +}
> +
> /*
> * These interfaces resemble the pci_find_*capability() interfaces, but these
> * are for configuring host controllers, which are bridges *to* PCI devices but
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index 6b81530fb2ca..7899808bdbc6 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -85,6 +85,9 @@
> #define PCIE_PORT_MULTI_LANE_CTRL 0x8C0
> #define PORT_MLTI_UPCFG_SUPPORT BIT(7)
>
> +#define PCIE_VERSION_NUMBER 0x8F8
> +#define PCIE_VERSION_TYPE 0x8FC
> +
> #define PCIE_ATU_VIEWPORT 0x900
> #define PCIE_ATU_REGION_INBOUND BIT(31)
> #define PCIE_ATU_REGION_OUTBOUND 0
> @@ -279,6 +282,7 @@ struct dw_pcie {
> struct dw_pcie_ep ep;
> const struct dw_pcie_ops *ops;
> u32 version;
> + u32 type;
> int num_lanes;
> int link_gen;
> u8 n_fts[2];
> @@ -290,6 +294,8 @@ struct dw_pcie {
> #define to_dw_pcie_from_ep(endpoint) \
> container_of((endpoint), struct dw_pcie, ep)
>
> +void dw_pcie_version_detect(struct dw_pcie *pci);
> +
> u8 dw_pcie_find_capability(struct dw_pcie *pci, u8 cap);
> u16 dw_pcie_find_ext_capability(struct dw_pcie *pci, u8 cap);
>
> --
> 2.35.1
>

--
மணிவண்ணன் சதாசிவம்