| Message ID | 20210803074932.19820-3-kishon@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | PCI: Add support for J7200 and AM64 | expand |
On Tue, Aug 03, 2021 at 01:19:28PM +0530, Kishon Vijay Abraham I wrote: > From: Nadeem Athani <nadeem@cadence.com> > > PCIe fails to link up if SERDES lanes not used by PCIe are assigned to > another protocol. For example, link training fails if lanes 2 and 3 are > assigned to another protocol while lanes 0 and 1 are used for PCIe to > form a two lane link. This failure is due to an incorrect tie-off on an > internal status signal indicating electrical idle. > > Status signals going from SERDES to PCIe Controller are tied-off when a > lane is not assigned to PCIe. Signal indicating electrical idle is > incorrectly tied-off to a state that indicates non-idle. As a result, > PCIe sees unused lanes to be out of electrical idle and this causes > LTSSM to exit Detect.Quiet state without waiting for 12ms timeout to > occur. If a receiver is not detected on the first receiver detection > attempt in Detect.Active state, LTSSM goes back to Detect.Quiet and > again moves forward to Detect.Active state without waiting for 12ms as > required by PCIe base specification. Since wait time in Detect.Quiet is > skipped, multiple receiver detect operations are performed back-to-back > without allowing time for capacitance on the transmit lines to > discharge. This causes subsequent receiver detection to always fail even > if a receiver gets connected eventually. > > Add a quirk flag "quirk_detect_quiet_flag" to program the minimum > time the LTSSM should wait on entering Detect.Quiet state here. > This has to be set for J7200 as it has an incorrect tie-off on unused > lanes. > > Signed-off-by: Nadeem Athani <nadeem@cadence.com> > Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com> > --- > .../pci/controller/cadence/pcie-cadence-ep.c | 4 ++++ > .../pci/controller/cadence/pcie-cadence-host.c | 3 +++ > drivers/pci/controller/cadence/pcie-cadence.c | 17 +++++++++++++++++ > drivers/pci/controller/cadence/pcie-cadence.h | 15 +++++++++++++++ > 4 files changed, 39 insertions(+) > > diff --git a/drivers/pci/controller/cadence/pcie-cadence-ep.c b/drivers/pci/controller/cadence/pcie-cadence-ep.c > index 791915054ff4..e05c157afef0 100644 > --- a/drivers/pci/controller/cadence/pcie-cadence-ep.c > +++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c > @@ -804,6 +804,10 @@ int cdns_pcie_ep_setup(struct cdns_pcie_ep *ep) > ep->irq_pci_addr = CDNS_PCIE_EP_IRQ_PCI_ADDR_NONE; > /* Reserve region 0 for IRQs */ > set_bit(0, &ep->ob_region_map); > + > + if (ep->quirk_detect_quiet_flag) > + cdns_pcie_detect_quiet_min_delay_set(&ep->pcie); > + > spin_lock_init(&ep->lock); > > return 0; > diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c > index ae1c55503513..fb96d37a135c 100644 > --- a/drivers/pci/controller/cadence/pcie-cadence-host.c > +++ b/drivers/pci/controller/cadence/pcie-cadence-host.c > @@ -498,6 +498,9 @@ int cdns_pcie_host_setup(struct cdns_pcie_rc *rc) > return PTR_ERR(rc->cfg_base); > rc->cfg_res = res; > > + if (rc->quirk_detect_quiet_flag) > + cdns_pcie_detect_quiet_min_delay_set(&rc->pcie); > + > ret = cdns_pcie_start_link(pcie); > if (ret) { > dev_err(dev, "Failed to start link\n"); > diff --git a/drivers/pci/controller/cadence/pcie-cadence.c b/drivers/pci/controller/cadence/pcie-cadence.c > index 3c3646502d05..65b6c8bed0d4 100644 > --- a/drivers/pci/controller/cadence/pcie-cadence.c > +++ b/drivers/pci/controller/cadence/pcie-cadence.c > @@ -7,6 +7,23 @@ > > #include "pcie-cadence.h" > > +void cdns_pcie_detect_quiet_min_delay_set(struct cdns_pcie *pcie) > +{ > + u32 delay = 0x3; > + u32 ltssm_control_cap; > + > + /* > + * Set the LTSSM Detect Quiet state min. delay to 2ms. > + */ > + Nit: empty line not needed > + ltssm_control_cap = cdns_pcie_readl(pcie, CDNS_PCIE_LTSSM_CONTROL_CAP); > + ltssm_control_cap = ((ltssm_control_cap & > + ~CDNS_PCIE_DETECT_QUIET_MIN_DELAY_MASK) | > + CDNS_PCIE_DETECT_QUIET_MIN_DELAY(delay)); > + > + cdns_pcie_writel(pcie, CDNS_PCIE_LTSSM_CONTROL_CAP, ltssm_control_cap); > +} > + > void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u8 busnr, u8 fn, > u32 r, bool is_io, > u64 cpu_addr, u64 pci_addr, size_t size) > diff --git a/drivers/pci/controller/cadence/pcie-cadence.h b/drivers/pci/controller/cadence/pcie-cadence.h > index a978a2eeedad..cda430d0f6e4 100644 > --- a/drivers/pci/controller/cadence/pcie-cadence.h > +++ b/drivers/pci/controller/cadence/pcie-cadence.h > @@ -194,6 +194,14 @@ > /* AXI link down register */ > #define CDNS_PCIE_AT_LINKDOWN (CDNS_PCIE_AT_BASE + 0x0824) > > +/* LTSSM Capabilities register */ > +#define CDNS_PCIE_LTSSM_CONTROL_CAP (CDNS_PCIE_LM_BASE + 0x0054) > +#define CDNS_PCIE_DETECT_QUIET_MIN_DELAY_MASK GENMASK(2, 1) > +#define CDNS_PCIE_DETECT_QUIET_MIN_DELAY_SHIFT 1 > +#define CDNS_PCIE_DETECT_QUIET_MIN_DELAY(delay) \ > + (((delay) << CDNS_PCIE_DETECT_QUIET_MIN_DELAY_SHIFT) & \ > + CDNS_PCIE_DETECT_QUIET_MIN_DELAY_MASK) > + > enum cdns_pcie_rp_bar { > RP_BAR_UNDEFINED = -1, > RP_BAR0, > @@ -300,6 +308,7 @@ struct cdns_pcie { > * @avail_ib_bar: Satus of RP_BAR0, RP_BAR1 and RP_NO_BAR if it's free or > * available > * @quirk_retrain_flag: Retrain link as quirk for PCIe Gen2 > + * @quirk_detect_quiet_flag: LTSSM Detect Quiet min delay set as quirk > */ > struct cdns_pcie_rc { > struct cdns_pcie pcie; > @@ -309,6 +318,7 @@ struct cdns_pcie_rc { > u32 device_id; > bool avail_ib_bar[CDNS_PCIE_RP_MAX_IB]; > unsigned int quirk_retrain_flag:1; > + unsigned int quirk_detect_quiet_flag:1; > }; > > /** > @@ -341,6 +351,7 @@ struct cdns_pcie_epf { > * registers fields (RMW) accessible by both remote RC and EP to > * minimize time between read and write > * @epf: Structure to hold info about endpoint function > + * @quirk_detect_quiet_flag: LTSSM Detect Quiet min delay set as quirk > */ > struct cdns_pcie_ep { > struct cdns_pcie pcie; > @@ -355,6 +366,7 @@ struct cdns_pcie_ep { > /* protect writing to PCI_STATUS while raising legacy interrupts */ > spinlock_t lock; > struct cdns_pcie_epf *epf; > + unsigned int quirk_detect_quiet_flag:1; > }; > > > @@ -515,6 +527,9 @@ static inline int cdns_pcie_ep_setup(struct cdns_pcie_ep *ep) > return 0; > } > #endif > + > +void cdns_pcie_detect_quiet_min_delay_set(struct cdns_pcie *pcie); > + > void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u8 busnr, u8 fn, > u32 r, bool is_io, > u64 cpu_addr, u64 pci_addr, size_t size); > -- > 2.17.1 >
diff --git a/drivers/pci/controller/cadence/pcie-cadence-ep.c b/drivers/pci/controller/cadence/pcie-cadence-ep.c index 791915054ff4..e05c157afef0 100644 --- a/drivers/pci/controller/cadence/pcie-cadence-ep.c +++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c @@ -804,6 +804,10 @@ int cdns_pcie_ep_setup(struct cdns_pcie_ep *ep) ep->irq_pci_addr = CDNS_PCIE_EP_IRQ_PCI_ADDR_NONE; /* Reserve region 0 for IRQs */ set_bit(0, &ep->ob_region_map); + + if (ep->quirk_detect_quiet_flag) + cdns_pcie_detect_quiet_min_delay_set(&ep->pcie); + spin_lock_init(&ep->lock); return 0; diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c index ae1c55503513..fb96d37a135c 100644 --- a/drivers/pci/controller/cadence/pcie-cadence-host.c +++ b/drivers/pci/controller/cadence/pcie-cadence-host.c @@ -498,6 +498,9 @@ int cdns_pcie_host_setup(struct cdns_pcie_rc *rc) return PTR_ERR(rc->cfg_base); rc->cfg_res = res; + if (rc->quirk_detect_quiet_flag) + cdns_pcie_detect_quiet_min_delay_set(&rc->pcie); + ret = cdns_pcie_start_link(pcie); if (ret) { dev_err(dev, "Failed to start link\n"); diff --git a/drivers/pci/controller/cadence/pcie-cadence.c b/drivers/pci/controller/cadence/pcie-cadence.c index 3c3646502d05..65b6c8bed0d4 100644 --- a/drivers/pci/controller/cadence/pcie-cadence.c +++ b/drivers/pci/controller/cadence/pcie-cadence.c @@ -7,6 +7,23 @@ #include "pcie-cadence.h" +void cdns_pcie_detect_quiet_min_delay_set(struct cdns_pcie *pcie) +{ + u32 delay = 0x3; + u32 ltssm_control_cap; + + /* + * Set the LTSSM Detect Quiet state min. delay to 2ms. + */ + + ltssm_control_cap = cdns_pcie_readl(pcie, CDNS_PCIE_LTSSM_CONTROL_CAP); + ltssm_control_cap = ((ltssm_control_cap & + ~CDNS_PCIE_DETECT_QUIET_MIN_DELAY_MASK) | + CDNS_PCIE_DETECT_QUIET_MIN_DELAY(delay)); + + cdns_pcie_writel(pcie, CDNS_PCIE_LTSSM_CONTROL_CAP, ltssm_control_cap); +} + void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u8 busnr, u8 fn, u32 r, bool is_io, u64 cpu_addr, u64 pci_addr, size_t size) diff --git a/drivers/pci/controller/cadence/pcie-cadence.h b/drivers/pci/controller/cadence/pcie-cadence.h index a978a2eeedad..cda430d0f6e4 100644 --- a/drivers/pci/controller/cadence/pcie-cadence.h +++ b/drivers/pci/controller/cadence/pcie-cadence.h @@ -194,6 +194,14 @@ /* AXI link down register */ #define CDNS_PCIE_AT_LINKDOWN (CDNS_PCIE_AT_BASE + 0x0824) +/* LTSSM Capabilities register */ +#define CDNS_PCIE_LTSSM_CONTROL_CAP (CDNS_PCIE_LM_BASE + 0x0054) +#define CDNS_PCIE_DETECT_QUIET_MIN_DELAY_MASK GENMASK(2, 1) +#define CDNS_PCIE_DETECT_QUIET_MIN_DELAY_SHIFT 1 +#define CDNS_PCIE_DETECT_QUIET_MIN_DELAY(delay) \ + (((delay) << CDNS_PCIE_DETECT_QUIET_MIN_DELAY_SHIFT) & \ + CDNS_PCIE_DETECT_QUIET_MIN_DELAY_MASK) + enum cdns_pcie_rp_bar { RP_BAR_UNDEFINED = -1, RP_BAR0, @@ -300,6 +308,7 @@ struct cdns_pcie { * @avail_ib_bar: Satus of RP_BAR0, RP_BAR1 and RP_NO_BAR if it's free or * available * @quirk_retrain_flag: Retrain link as quirk for PCIe Gen2 + * @quirk_detect_quiet_flag: LTSSM Detect Quiet min delay set as quirk */ struct cdns_pcie_rc { struct cdns_pcie pcie; @@ -309,6 +318,7 @@ struct cdns_pcie_rc { u32 device_id; bool avail_ib_bar[CDNS_PCIE_RP_MAX_IB]; unsigned int quirk_retrain_flag:1; + unsigned int quirk_detect_quiet_flag:1; }; /** @@ -341,6 +351,7 @@ struct cdns_pcie_epf { * registers fields (RMW) accessible by both remote RC and EP to * minimize time between read and write * @epf: Structure to hold info about endpoint function + * @quirk_detect_quiet_flag: LTSSM Detect Quiet min delay set as quirk */ struct cdns_pcie_ep { struct cdns_pcie pcie; @@ -355,6 +366,7 @@ struct cdns_pcie_ep { /* protect writing to PCI_STATUS while raising legacy interrupts */ spinlock_t lock; struct cdns_pcie_epf *epf; + unsigned int quirk_detect_quiet_flag:1; }; @@ -515,6 +527,9 @@ static inline int cdns_pcie_ep_setup(struct cdns_pcie_ep *ep) return 0; } #endif + +void cdns_pcie_detect_quiet_min_delay_set(struct cdns_pcie *pcie); + void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u8 busnr, u8 fn, u32 r, bool is_io, u64 cpu_addr, u64 pci_addr, size_t size);