* [PATCH v3] PCI: cadence: Retrain Link to work around Gen2 training defect.
@ 2020-09-30 18:21 Nadeem Athani
2020-10-19 5:28 ` Kishon Vijay Abraham I
0 siblings, 1 reply; 7+ messages in thread
From: Nadeem Athani @ 2020-09-30 18:21 UTC (permalink / raw)
To: lorenzo.pieralisi, robh, bhelgaas, linux-pci, linux-kernel,
kishon, tjoseph
Cc: nadeem, sjakhade, mparab
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 <nadeem@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;
+
+ /*
+ * 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))
+ 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)
--
2.15.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v3] PCI: cadence: Retrain Link to work around Gen2 training defect.
2020-09-30 18:21 [PATCH v3] PCI: cadence: Retrain Link to work around Gen2 training defect Nadeem Athani
@ 2020-10-19 5:28 ` Kishon Vijay Abraham I
2020-10-19 17:18 ` Athani Nadeem Ladkhan
0 siblings, 1 reply; 7+ messages in thread
From: Kishon Vijay Abraham I @ 2020-10-19 5:28 UTC (permalink / raw)
To: Nadeem Athani, lorenzo.pieralisi, robh, bhelgaas, linux-pci,
linux-kernel, tjoseph
Cc: sjakhade, mparab
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 <nadeem@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)
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [PATCH v3] PCI: cadence: Retrain Link to work around Gen2 training defect.
2020-10-19 5:28 ` Kishon Vijay Abraham I
@ 2020-10-19 17:18 ` Athani Nadeem Ladkhan
2020-10-23 6:56 ` Kishon Vijay Abraham I
0 siblings, 1 reply; 7+ messages in thread
From: Athani Nadeem Ladkhan @ 2020-10-19 17:18 UTC (permalink / raw)
To: Kishon Vijay Abraham I, lorenzo.pieralisi, robh, bhelgaas,
linux-pci, linux-kernel, Tom Joseph
Cc: Swapnil Kashinath Jakhade, Milind Parab
Hi Kishon,
> -----Original Message-----
> From: Kishon Vijay Abraham I <kishon@ti.com>
> Sent: Monday, October 19, 2020 10:59 AM
> To: Athani Nadeem Ladkhan <nadeem@cadence.com>;
> lorenzo.pieralisi@arm.com; robh@kernel.org; bhelgaas@google.com; linux-
> pci@vger.kernel.org; linux-kernel@vger.kernel.org; Tom Joseph
> <tjoseph@cadence.com>
> Cc: Swapnil Kashinath Jakhade <sjakhade@cadence.com>; Milind Parab
> <mparab@cadence.com>
> Subject: Re: [PATCH v3] PCI: cadence: Retrain Link to work around Gen2
> training defect.
>
> EXTERNAL MAIL
>
>
> 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 <nadeem@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?
There is no such provision.
> > + /*
> > + * 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()?
The use of this api cdns_pcie_link_up was mentioned in earlier reviews.
The mentioned api cdns_pcie_host_wait_for_link is a wrapper in which there are multiple checks.
If insist, will replace with it.
Thanks,
Nadeem
>
> 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)
> >
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3] PCI: cadence: Retrain Link to work around Gen2 training defect.
2020-10-19 17:18 ` Athani Nadeem Ladkhan
@ 2020-10-23 6:56 ` Kishon Vijay Abraham I
2020-10-26 19:20 ` Rob Herring
0 siblings, 1 reply; 7+ messages in thread
From: Kishon Vijay Abraham I @ 2020-10-23 6:56 UTC (permalink / raw)
To: Athani Nadeem Ladkhan, lorenzo.pieralisi, robh, bhelgaas,
linux-pci, linux-kernel, Tom Joseph
Cc: Swapnil Kashinath Jakhade, Milind Parab
Hi Nadeem,
On 19/10/20 10:48 pm, Athani Nadeem Ladkhan wrote:
> Hi Kishon,
>
>> -----Original Message-----
>> From: Kishon Vijay Abraham I <kishon@ti.com>
>> Sent: Monday, October 19, 2020 10:59 AM
>> To: Athani Nadeem Ladkhan <nadeem@cadence.com>;
>> lorenzo.pieralisi@arm.com; robh@kernel.org; bhelgaas@google.com; linux-
>> pci@vger.kernel.org; linux-kernel@vger.kernel.org; Tom Joseph
>> <tjoseph@cadence.com>
>> Cc: Swapnil Kashinath Jakhade <sjakhade@cadence.com>; Milind Parab
>> <mparab@cadence.com>
>> Subject: Re: [PATCH v3] PCI: cadence: Retrain Link to work around Gen2
>> training defect.
>>
>> EXTERNAL MAIL
>>
>>
>> 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 <nadeem@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?
> There is no such provision.
hmm okay. Can we add a DT property to indicate the quirk then since
AFAIK this is not required in future revisions of IP.
>>> + /*
>>> + * 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()?
> The use of this api cdns_pcie_link_up was mentioned in earlier reviews.
> The mentioned api cdns_pcie_host_wait_for_link is a wrapper in which there are multiple checks.
> If insist, will replace with it.
yeah, I think we should give some time for the link up to succeed after
re-training.
Thanks
Kishon
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3] PCI: cadence: Retrain Link to work around Gen2 training defect.
2020-10-23 6:56 ` Kishon Vijay Abraham I
@ 2020-10-26 19:20 ` Rob Herring
2020-11-26 13:58 ` Kishon Vijay Abraham I
0 siblings, 1 reply; 7+ messages in thread
From: Rob Herring @ 2020-10-26 19:20 UTC (permalink / raw)
To: Kishon Vijay Abraham I
Cc: Athani Nadeem Ladkhan, lorenzo.pieralisi, bhelgaas, linux-pci,
linux-kernel, Tom Joseph, Swapnil Kashinath Jakhade,
Milind Parab
On Fri, Oct 23, 2020 at 1:57 AM Kishon Vijay Abraham I <kishon@ti.com> wrote:
>
> Hi Nadeem,
>
> On 19/10/20 10:48 pm, Athani Nadeem Ladkhan wrote:
> > Hi Kishon,
> >
> >> -----Original Message-----
> >> From: Kishon Vijay Abraham I <kishon@ti.com>
> >> Sent: Monday, October 19, 2020 10:59 AM
> >> To: Athani Nadeem Ladkhan <nadeem@cadence.com>;
> >> lorenzo.pieralisi@arm.com; robh@kernel.org; bhelgaas@google.com; linux-
> >> pci@vger.kernel.org; linux-kernel@vger.kernel.org; Tom Joseph
> >> <tjoseph@cadence.com>
> >> Cc: Swapnil Kashinath Jakhade <sjakhade@cadence.com>; Milind Parab
> >> <mparab@cadence.com>
> >> Subject: Re: [PATCH v3] PCI: cadence: Retrain Link to work around Gen2
> >> training defect.
> >>
> >> EXTERNAL MAIL
> >>
> >>
> >> 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 <nadeem@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?
> > There is no such provision.
Cadence just gives out unversioned IP? There may not be s/w readable
version, but there's still a version. Look at DWC.
> hmm okay. Can we add a DT property to indicate the quirk then since
> AFAIK this is not required in future revisions of IP.
No, add a driver quirk flag, but set flag that based on compatible strings.
> >>> + /*
> >>> + * Set retrain bit if current speed is 2.5 GB/s,
> >>> + * but the PCIe root port support is > 2.5 GB/s.
Though wouldn't setting the retrain bit be harmless even if not needed?
Rob
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v3] PCI: cadence: Retrain Link to work around Gen2 training defect.
2020-10-26 19:20 ` Rob Herring
@ 2020-11-26 13:58 ` Kishon Vijay Abraham I
2020-12-01 15:15 ` Athani Nadeem Ladkhan
0 siblings, 1 reply; 7+ messages in thread
From: Kishon Vijay Abraham I @ 2020-11-26 13:58 UTC (permalink / raw)
To: Rob Herring
Cc: Athani Nadeem Ladkhan, lorenzo.pieralisi, bhelgaas, linux-pci,
linux-kernel, Tom Joseph, Swapnil Kashinath Jakhade,
Milind Parab
Hi Tom, Nadeem,
On 27/10/20 12:50 am, Rob Herring wrote:
> On Fri, Oct 23, 2020 at 1:57 AM Kishon Vijay Abraham I <kishon@ti.com> wrote:
>>
>> Hi Nadeem,
>>
>> On 19/10/20 10:48 pm, Athani Nadeem Ladkhan wrote:
>>> Hi Kishon,
>>>
>>>> -----Original Message-----
>>>> From: Kishon Vijay Abraham I <kishon@ti.com>
>>>> Sent: Monday, October 19, 2020 10:59 AM
>>>> To: Athani Nadeem Ladkhan <nadeem@cadence.com>;
>>>> lorenzo.pieralisi@arm.com; robh@kernel.org; bhelgaas@google.com; linux-
>>>> pci@vger.kernel.org; linux-kernel@vger.kernel.org; Tom Joseph
>>>> <tjoseph@cadence.com>
>>>> Cc: Swapnil Kashinath Jakhade <sjakhade@cadence.com>; Milind Parab
>>>> <mparab@cadence.com>
>>>> Subject: Re: [PATCH v3] PCI: cadence: Retrain Link to work around Gen2
>>>> training defect.
>>>>
>>>> EXTERNAL MAIL
>>>>
>>>>
>>>> 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 <nadeem@cadence.com>
Do you have a follow-up patch fixing the review comments?
Thanks
Kishon
^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [PATCH v3] PCI: cadence: Retrain Link to work around Gen2 training defect.
2020-11-26 13:58 ` Kishon Vijay Abraham I
@ 2020-12-01 15:15 ` Athani Nadeem Ladkhan
0 siblings, 0 replies; 7+ messages in thread
From: Athani Nadeem Ladkhan @ 2020-12-01 15:15 UTC (permalink / raw)
To: Kishon Vijay Abraham I, Rob Herring
Cc: lorenzo.pieralisi, bhelgaas, linux-pci, linux-kernel, Tom Joseph,
Swapnil Kashinath Jakhade, Milind Parab
Hi Kishon,
> -----Original Message-----
> From: Kishon Vijay Abraham I <kishon@ti.com>
> Sent: Thursday, November 26, 2020 7:28 PM
> To: Rob Herring <robh@kernel.org>
> Cc: Athani Nadeem Ladkhan <nadeem@cadence.com>;
> lorenzo.pieralisi@arm.com; bhelgaas@google.com; linux-
> pci@vger.kernel.org; linux-kernel@vger.kernel.org; Tom Joseph
> <tjoseph@cadence.com>; Swapnil Kashinath Jakhade
> <sjakhade@cadence.com>; Milind Parab <mparab@cadence.com>
> Subject: Re: [PATCH v3] PCI: cadence: Retrain Link to work around Gen2
> training defect.
>
> EXTERNAL MAIL
>
>
> Hi Tom, Nadeem,
>
> On 27/10/20 12:50 am, Rob Herring wrote:
> > On Fri, Oct 23, 2020 at 1:57 AM Kishon Vijay Abraham I <kishon@ti.com>
> wrote:
> >>
> >> Hi Nadeem,
> >>
> >> On 19/10/20 10:48 pm, Athani Nadeem Ladkhan wrote:
> >>> Hi Kishon,
> >>>
> >>>> -----Original Message-----
> >>>> From: Kishon Vijay Abraham I <kishon@ti.com>
> >>>> Sent: Monday, October 19, 2020 10:59 AM
> >>>> To: Athani Nadeem Ladkhan <nadeem@cadence.com>;
> >>>> lorenzo.pieralisi@arm.com; robh@kernel.org; bhelgaas@google.com;
> >>>> linux- pci@vger.kernel.org; linux-kernel@vger.kernel.org; Tom
> >>>> Joseph <tjoseph@cadence.com>
> >>>> Cc: Swapnil Kashinath Jakhade <sjakhade@cadence.com>; Milind Parab
> >>>> <mparab@cadence.com>
> >>>> Subject: Re: [PATCH v3] PCI: cadence: Retrain Link to work around
> >>>> Gen2 training defect.
> >>>>
> >>>> EXTERNAL MAIL
> >>>>
> >>>>
> >>>> 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 <nadeem@cadence.com>
>
> Do you have a follow-up patch fixing the review comments?
We planned to fix this in coming 3 weeks.
>
> Thanks
> Kishon
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-12-01 15:16 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-09-30 18:21 [PATCH v3] PCI: cadence: Retrain Link to work around Gen2 training defect Nadeem Athani
2020-10-19 5:28 ` Kishon Vijay Abraham I
2020-10-19 17:18 ` Athani Nadeem Ladkhan
2020-10-23 6:56 ` Kishon Vijay Abraham I
2020-10-26 19:20 ` Rob Herring
2020-11-26 13:58 ` Kishon Vijay Abraham I
2020-12-01 15:15 ` Athani Nadeem Ladkhan
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