| Message ID | 20210309073142.13219-3-nadeem@cadence.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Lorenzo Pieralisi |
| Headers | show |
| Series | PCI: cadence: Set LTSSM Detect.Quiet state delay. | expand |
Hi Nadeem, On 09/03/21 1:01 pm, Nadeem Athani wrote: > The parameter detect_quiet_min_delay can be used to program the minimum > time that LTSSM waits on entering Detect.Quiet state. > 00 : 0us minimum wait time in Detect.Quiet state. > 01 : 100us minimum wait time in Detect.Quiet state. > 10 : 1000us minimum wait time in Detect.Quiet state. > 11 : 2000us minimum wait time in Detect.Quiet state. > > As per PCIe specification, all Receivers must meet the Z-RX-DC > specification for 2.5 GT/s within 1000us of entering Detect.Quiet LTSSM > substate. The LTSSM must stay in this substate until the ZRXDC > specification for 2.5 GT/s is met. > > Signed-off-by: Nadeem Athani <nadeem@cadence.com> > --- > drivers/pci/controller/cadence/pcie-cadence-host.c | 22 ++++++++++++++++++++++ > drivers/pci/controller/cadence/pcie-cadence.h | 10 ++++++++++ > 2 files changed, 32 insertions(+) > > diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c > index 73dcf8cf98fb..056161b3fe65 100644 > --- a/drivers/pci/controller/cadence/pcie-cadence-host.c > +++ b/drivers/pci/controller/cadence/pcie-cadence-host.c > @@ -461,6 +461,20 @@ static int cdns_pcie_host_init(struct device *dev, > return cdns_pcie_host_init_address_translation(rc); > } > > +static void cdns_pcie_detect_quiet_min_delay_set(struct cdns_pcie_rc *rc) > +{ > + struct cdns_pcie *pcie = &rc->pcie; > + u32 delay = rc->detect_quiet_min_delay; > + u32 ltssm_control_cap; > + > + 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); > +} > + The issue is not specific to only host mode. Thanks Kishon > int cdns_pcie_host_setup(struct cdns_pcie_rc *rc) > { > struct device *dev = rc->pcie.dev; > @@ -485,6 +499,10 @@ int cdns_pcie_host_setup(struct cdns_pcie_rc *rc) > rc->device_id = 0xffff; > of_property_read_u32(np, "device-id", &rc->device_id); > > + rc->detect_quiet_min_delay = 0; > + of_property_read_u32(np, "detect-quiet-min-delay", > + &rc->detect_quiet_min_delay); > + > pcie->reg_base = devm_platform_ioremap_resource_byname(pdev, "reg"); > if (IS_ERR(pcie->reg_base)) { > dev_err(dev, "missing \"reg\"\n"); > @@ -497,6 +515,10 @@ int cdns_pcie_host_setup(struct cdns_pcie_rc *rc) > return PTR_ERR(rc->cfg_base); > rc->cfg_res = res; > > + /* Default Detect.Quiet state delay is 0 */ > + if (rc->detect_quiet_min_delay) > + cdns_pcie_detect_quiet_min_delay_set(rc); > + > 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.h b/drivers/pci/controller/cadence/pcie-cadence.h > index 254d2570f8c9..f2d3cca2c707 100644 > --- a/drivers/pci/controller/cadence/pcie-cadence.h > +++ b/drivers/pci/controller/cadence/pcie-cadence.h > @@ -189,6 +189,14 @@ > /* 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, > @@ -289,6 +297,7 @@ struct cdns_pcie { > * single function at a time > * @vendor_id: PCI vendor ID > * @device_id: PCI device ID > + * @detect_quiet_min_delay: LTSSM Detect Quite state min. delay > * @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 > @@ -299,6 +308,7 @@ struct cdns_pcie_rc { > void __iomem *cfg_base; > u32 vendor_id; > u32 device_id; > + u32 detect_quiet_min_delay; > bool avail_ib_bar[CDNS_PCIE_RP_MAX_IB]; > bool quirk_retrain_flag; > }; >
diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c index 73dcf8cf98fb..056161b3fe65 100644 --- a/drivers/pci/controller/cadence/pcie-cadence-host.c +++ b/drivers/pci/controller/cadence/pcie-cadence-host.c @@ -461,6 +461,20 @@ static int cdns_pcie_host_init(struct device *dev, return cdns_pcie_host_init_address_translation(rc); } +static void cdns_pcie_detect_quiet_min_delay_set(struct cdns_pcie_rc *rc) +{ + struct cdns_pcie *pcie = &rc->pcie; + u32 delay = rc->detect_quiet_min_delay; + u32 ltssm_control_cap; + + 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); +} + int cdns_pcie_host_setup(struct cdns_pcie_rc *rc) { struct device *dev = rc->pcie.dev; @@ -485,6 +499,10 @@ int cdns_pcie_host_setup(struct cdns_pcie_rc *rc) rc->device_id = 0xffff; of_property_read_u32(np, "device-id", &rc->device_id); + rc->detect_quiet_min_delay = 0; + of_property_read_u32(np, "detect-quiet-min-delay", + &rc->detect_quiet_min_delay); + pcie->reg_base = devm_platform_ioremap_resource_byname(pdev, "reg"); if (IS_ERR(pcie->reg_base)) { dev_err(dev, "missing \"reg\"\n"); @@ -497,6 +515,10 @@ int cdns_pcie_host_setup(struct cdns_pcie_rc *rc) return PTR_ERR(rc->cfg_base); rc->cfg_res = res; + /* Default Detect.Quiet state delay is 0 */ + if (rc->detect_quiet_min_delay) + cdns_pcie_detect_quiet_min_delay_set(rc); + 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.h b/drivers/pci/controller/cadence/pcie-cadence.h index 254d2570f8c9..f2d3cca2c707 100644 --- a/drivers/pci/controller/cadence/pcie-cadence.h +++ b/drivers/pci/controller/cadence/pcie-cadence.h @@ -189,6 +189,14 @@ /* 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, @@ -289,6 +297,7 @@ struct cdns_pcie { * single function at a time * @vendor_id: PCI vendor ID * @device_id: PCI device ID + * @detect_quiet_min_delay: LTSSM Detect Quite state min. delay * @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 @@ -299,6 +308,7 @@ struct cdns_pcie_rc { void __iomem *cfg_base; u32 vendor_id; u32 device_id; + u32 detect_quiet_min_delay; bool avail_ib_bar[CDNS_PCIE_RP_MAX_IB]; bool quirk_retrain_flag; };
The parameter detect_quiet_min_delay can be used to program the minimum time that LTSSM waits on entering Detect.Quiet state. 00 : 0us minimum wait time in Detect.Quiet state. 01 : 100us minimum wait time in Detect.Quiet state. 10 : 1000us minimum wait time in Detect.Quiet state. 11 : 2000us minimum wait time in Detect.Quiet state. As per PCIe specification, all Receivers must meet the Z-RX-DC specification for 2.5 GT/s within 1000us of entering Detect.Quiet LTSSM substate. The LTSSM must stay in this substate until the ZRXDC specification for 2.5 GT/s is met. Signed-off-by: Nadeem Athani <nadeem@cadence.com> --- drivers/pci/controller/cadence/pcie-cadence-host.c | 22 ++++++++++++++++++++++ drivers/pci/controller/cadence/pcie-cadence.h | 10 ++++++++++ 2 files changed, 32 insertions(+)