Hi Nadeem,
On 30/09/20 11:51 pm, Nadeem Athani wrote:
> Cadence controller will not initiate autonomous speed change if strapped
> as Gen2. The Retrain Link bit is set as quirk to enable this speed change.
>
> Signed-off-by: Nadeem Athani <nad...@cadence.com>
> ---
> Changes in v3:
> - To set retrain link bit,checking device capability & link status.
> - 32bit read in place of 8bit.
> - Minor correction in patch comment.
> - Change in variable & macro name.
> Changes in v2:
> - 16bit read in place of 8bit.
> drivers/pci/controller/cadence/pcie-cadence-host.c | 31
> ++++++++++++++++++++++
> drivers/pci/controller/cadence/pcie-cadence.h | 9 ++++++-
> 2 files changed, 39 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c
> b/drivers/pci/controller/cadence/pcie-cadence-host.c
> index 4550e0d469ca..2b2ae4e18032 100644
> --- a/drivers/pci/controller/cadence/pcie-cadence-host.c
> +++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
> @@ -77,6 +77,36 @@ static struct pci_ops cdns_pcie_host_ops = {
> .write = pci_generic_config_write,
> };
>
> +static void cdns_pcie_retrain(struct cdns_pcie *pcie)
> +{
> + u32 lnk_cap_sls, pcie_cap_off = CDNS_PCIE_RP_CAP_OFFSET;
> + u16 lnk_stat, lnk_ctl;
> +
> + if (!cdns_pcie_link_up(pcie))
> + return;
> +
Is there a IP version that can be used to check if that quirk is applicable?
> + /*
> + * Set retrain bit if current speed is 2.5 GB/s,
> + * but the PCIe root port support is > 2.5 GB/s.
> + */
> +
> + lnk_cap_sls = cdns_pcie_readl(pcie, (CDNS_PCIE_RP_BASE + pcie_cap_off +
> + PCI_EXP_LNKCAP));
> + if ((lnk_cap_sls & PCI_EXP_LNKCAP_SLS) <= PCI_EXP_LNKCAP_SLS_2_5GB)
> + return;
> +
> + lnk_stat = cdns_pcie_rp_readw(pcie, pcie_cap_off + PCI_EXP_LNKSTA);
> + if ((lnk_stat & PCI_EXP_LNKSTA_CLS) == PCI_EXP_LNKSTA_CLS_2_5GB) {
> + lnk_ctl = cdns_pcie_rp_readw(pcie,
> + pcie_cap_off + PCI_EXP_LNKCTL);
> + lnk_ctl |= PCI_EXP_LNKCTL_RL;
> + cdns_pcie_rp_writew(pcie, pcie_cap_off + PCI_EXP_LNKCTL,
> + lnk_ctl);
> +
> + if (!cdns_pcie_link_up(pcie))
Should this rather be a cdns_pcie_host_wait_for_link()?
Thanks
Kishon
> + return;
> + }
> +}
>
> static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
> {
> @@ -115,6 +145,7 @@ static int cdns_pcie_host_init_root_port(struct
> cdns_pcie_rc *rc)
> cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0);
> cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE, PCI_CLASS_BRIDGE_PCI);
>
> + cdns_pcie_retrain(pcie);
> return 0;
> }
>
> diff --git a/drivers/pci/controller/cadence/pcie-cadence.h
> b/drivers/pci/controller/cadence/pcie-cadence.h
> index feed1e3038f4..5f1cf032ae15 100644
> --- a/drivers/pci/controller/cadence/pcie-cadence.h
> +++ b/drivers/pci/controller/cadence/pcie-cadence.h
> @@ -119,7 +119,7 @@
> * Root Port Registers (PCI configuration space for the root port function)
> */
> #define CDNS_PCIE_RP_BASE 0x00200000
> -
> +#define CDNS_PCIE_RP_CAP_OFFSET 0xc0
>
> /*
> * Address Translation Registers
> @@ -413,6 +413,13 @@ static inline void cdns_pcie_rp_writew(struct cdns_pcie
> *pcie,
> cdns_pcie_write_sz(addr, 0x2, value);
> }
>
> +static inline u16 cdns_pcie_rp_readw(struct cdns_pcie *pcie, u32 reg)
> +{
> + void __iomem *addr = pcie->reg_base + CDNS_PCIE_RP_BASE + reg;
> +
> + return cdns_pcie_read_sz(addr, 0x2);
> +}
> +
> /* Endpoint Function register access */
> static inline void cdns_pcie_ep_fn_writeb(struct cdns_pcie *pcie, u8 fn,
> u32 reg, u8 value)
>
