2020-09-18 11:25:48

by Athani Nadeem Ladkhan

Subject: [PATCH] PCI: Cadence: Add quirk for Gen2 controller to do autonomous speed change.

Cadence controller will not initiate autonomous speed change if
strapped as Gen2. The Retrain bit is set as a quirk to trigger
this speed change.

Signed-off-by: Nadeem Athani <[email protected]>
---
drivers/pci/controller/cadence/pcie-cadence-host.c | 13 +++++++++++++
drivers/pci/controller/cadence/pcie-cadence.h | 6 ++++++
2 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c
index 4550e0d..4cb7f29 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-host.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
@@ -83,6 +83,8 @@ static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
struct cdns_pcie *pcie = &rc->pcie;
u32 value, ctrl;
u32 id;
+ u32 link_cap = CDNS_PCIE_LINK_CAP_OFFSET;
+ u8 sls, lnk_ctl;

/*
* Set the root complex BAR configuration register:
@@ -111,6 +113,17 @@ static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
if (rc->device_id != 0xffff)
cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID, rc->device_id);

+ /* Quirk to enable autonomous speed change for GEN2 controller */
+ /* Reading Supported Link Speed value */
+ sls = PCI_EXP_LNKCAP_SLS &
+ cdns_pcie_rp_readb(pcie, link_cap + PCI_EXP_LNKCAP);
+ if (sls == PCI_EXP_LNKCAP_SLS_5_0GB) {
+ /* Since this a Gen2 controller, set Retrain Link(RL) bit */
+ lnk_ctl = cdns_pcie_rp_readb(pcie, link_cap + PCI_EXP_LNKCTL);
+ lnk_ctl |= PCI_EXP_LNKCTL_RL;
+ cdns_pcie_rp_writeb(pcie, link_cap + PCI_EXP_LNKCTL, lnk_ctl);
+ }
+
cdns_pcie_rp_writeb(pcie, PCI_CLASS_REVISION, 0);
cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0);
cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE, PCI_CLASS_BRIDGE_PCI);
diff --git a/drivers/pci/controller/cadence/pcie-cadence.h b/drivers/pci/controller/cadence/pcie-cadence.h
index feed1e3..075c263 100644
--- a/drivers/pci/controller/cadence/pcie-cadence.h
+++ b/drivers/pci/controller/cadence/pcie-cadence.h
@@ -120,6 +120,7 @@
*/
#define CDNS_PCIE_RP_BASE 0x00200000

+#define CDNS_PCIE_LINK_CAP_OFFSET 0xC0

/*
* Address Translation Registers
@@ -413,6 +414,11 @@ static inline void cdns_pcie_rp_writew(struct cdns_pcie *pcie,
cdns_pcie_write_sz(addr, 0x2, value);
}

+static inline u8 cdns_pcie_rp_readb(struct cdns_pcie *pcie, u32 reg)
+{
+ return readb(pcie->reg_base + CDNS_PCIE_RP_BASE + reg);
+}
+
/* Endpoint Function register access */
static inline void cdns_pcie_ep_fn_writeb(struct cdns_pcie *pcie, u8 fn,
u32 reg, u8 value)
--
1.7.1

2020-09-22 17:40:22

by Rob Herring (Arm)

Subject: Re: [PATCH] PCI: Cadence: Add quirk for Gen2 controller to do autonomous speed change.

On Fri, Sep 18, 2020 at 4:34 AM Nadeem Athani <[email protected]> wrote:
>
> Cadence controller will not initiate autonomous speed change if
> strapped as Gen2. The Retrain bit is set as a quirk to trigger
> this speed change.
>
> Signed-off-by: Nadeem Athani <[email protected]>
> ---
> drivers/pci/controller/cadence/pcie-cadence-host.c | 13 +++++++++++++
> drivers/pci/controller/cadence/pcie-cadence.h | 6 ++++++
> 2 files changed, 19 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c
> index 4550e0d..4cb7f29 100644
> --- a/drivers/pci/controller/cadence/pcie-cadence-host.c
> +++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
> @@ -83,6 +83,8 @@ static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
> struct cdns_pcie *pcie = &rc->pcie;
> u32 value, ctrl;
> u32 id;
> + u32 link_cap = CDNS_PCIE_LINK_CAP_OFFSET;
> + u8 sls, lnk_ctl;
>
> /*
> * Set the root complex BAR configuration register:
> @@ -111,6 +113,17 @@ static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
> if (rc->device_id != 0xffff)
> cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID, rc->device_id);
>
> + /* Quirk to enable autonomous speed change for GEN2 controller */
> + /* Reading Supported Link Speed value */
> + sls = PCI_EXP_LNKCAP_SLS &
> + cdns_pcie_rp_readb(pcie, link_cap + PCI_EXP_LNKCAP);
> + if (sls == PCI_EXP_LNKCAP_SLS_5_0GB) {
> + /* Since this a Gen2 controller, set Retrain Link(RL) bit */
> + lnk_ctl = cdns_pcie_rp_readb(pcie, link_cap + PCI_EXP_LNKCTL);
> + lnk_ctl |= PCI_EXP_LNKCTL_RL;
> + cdns_pcie_rp_writeb(pcie, link_cap + PCI_EXP_LNKCTL, lnk_ctl);

Why the byte accesses? This is a 16-bit register.

> + }
> +
> cdns_pcie_rp_writeb(pcie, PCI_CLASS_REVISION, 0);
> cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0);
> cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE, PCI_CLASS_BRIDGE_PCI);
> diff --git a/drivers/pci/controller/cadence/pcie-cadence.h b/drivers/pci/controller/cadence/pcie-cadence.h
> index feed1e3..075c263 100644
> --- a/drivers/pci/controller/cadence/pcie-cadence.h
> +++ b/drivers/pci/controller/cadence/pcie-cadence.h
> @@ -120,6 +120,7 @@
> */
> #define CDNS_PCIE_RP_BASE 0x00200000
>
> +#define CDNS_PCIE_LINK_CAP_OFFSET 0xC0
>
> /*
> * Address Translation Registers
> @@ -413,6 +414,11 @@ static inline void cdns_pcie_rp_writew(struct cdns_pcie *pcie,
> cdns_pcie_write_sz(addr, 0x2, value);
> }
>
> +static inline u8 cdns_pcie_rp_readb(struct cdns_pcie *pcie, u32 reg)
> +{
> + return readb(pcie->reg_base + CDNS_PCIE_RP_BASE + reg);
> +}
> +
> /* Endpoint Function register access */
> static inline void cdns_pcie_ep_fn_writeb(struct cdns_pcie *pcie, u8 fn,
> u32 reg, u8 value)
> --
> 1.7.1
>

2020-09-23 07:58:06

by Athani Nadeem Ladkhan

Subject: RE: [PATCH] PCI: Cadence: Add quirk for Gen2 controller to do autonomous speed change.

Hi Rob,

> -----Original Message-----
> From: Rob Herring <[email protected]>
> Sent: Tuesday, September 22, 2020 11:08 PM
> To: Athani Nadeem Ladkhan <[email protected]>
> Cc: Tom Joseph <[email protected]>; Lorenzo Pieralisi
> <[email protected]>; Bjorn Helgaas <[email protected]>; PCI
> <[email protected]>; [email protected]; Milind Parab
> <[email protected]>; Swapnil Kashinath Jakhade
> <[email protected]>
> Subject: Re: [PATCH] PCI: Cadence: Add quirk for Gen2 controller to do
> autonomous speed change.
>
> EXTERNAL MAIL
>
>
> On Fri, Sep 18, 2020 at 4:34 AM Nadeem Athani <[email protected]>
> wrote:
> >
> > Cadence controller will not initiate autonomous speed change if
> > strapped as Gen2. The Retrain bit is set as a quirk to trigger this
> > speed change.
> >
> > Signed-off-by: Nadeem Athani <[email protected]>
> > ---
> > drivers/pci/controller/cadence/pcie-cadence-host.c | 13 +++++++++++++
> > drivers/pci/controller/cadence/pcie-cadence.h | 6 ++++++
> > 2 files changed, 19 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c
> > b/drivers/pci/controller/cadence/pcie-cadence-host.c
> > index 4550e0d..4cb7f29 100644
> > --- a/drivers/pci/controller/cadence/pcie-cadence-host.c
> > +++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
> > @@ -83,6 +83,8 @@ static int cdns_pcie_host_init_root_port(struct
> cdns_pcie_rc *rc)
> > struct cdns_pcie *pcie = &rc->pcie;
> > u32 value, ctrl;
> > u32 id;
> > + u32 link_cap = CDNS_PCIE_LINK_CAP_OFFSET;
> > + u8 sls, lnk_ctl;
> >
> > /*
> > * Set the root complex BAR configuration register:
> > @@ -111,6 +113,17 @@ static int cdns_pcie_host_init_root_port(struct
> cdns_pcie_rc *rc)
> > if (rc->device_id != 0xffff)
> > cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID,
> > rc->device_id);
> >
> > + /* Quirk to enable autonomous speed change for GEN2 controller */
> > + /* Reading Supported Link Speed value */
> > + sls = PCI_EXP_LNKCAP_SLS &
> > + cdns_pcie_rp_readb(pcie, link_cap + PCI_EXP_LNKCAP);
> > + if (sls == PCI_EXP_LNKCAP_SLS_5_0GB) {
> > + /* Since this a Gen2 controller, set Retrain Link(RL) bit */
> > + lnk_ctl = cdns_pcie_rp_readb(pcie, link_cap + PCI_EXP_LNKCTL);
> > + lnk_ctl |= PCI_EXP_LNKCTL_RL;
> > + cdns_pcie_rp_writeb(pcie, link_cap + PCI_EXP_LNKCTL,
> > + lnk_ctl);
>
> Why the byte accesses? This is a 16-bit register.
This is a 32bit register. But the register field require is at first byte only. Hence the byte access.
>
> > + }
> > +
> > cdns_pcie_rp_writeb(pcie, PCI_CLASS_REVISION, 0);
> > cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0);
> > cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE,
> > PCI_CLASS_BRIDGE_PCI); diff --git
> > a/drivers/pci/controller/cadence/pcie-cadence.h
> > b/drivers/pci/controller/cadence/pcie-cadence.h
> > index feed1e3..075c263 100644
> > --- a/drivers/pci/controller/cadence/pcie-cadence.h
> > +++ b/drivers/pci/controller/cadence/pcie-cadence.h
> > @@ -120,6 +120,7 @@
> > */
> > #define CDNS_PCIE_RP_BASE 0x00200000
> >
> > +#define CDNS_PCIE_LINK_CAP_OFFSET 0xC0
> >
> > /*
> > * Address Translation Registers
> > @@ -413,6 +414,11 @@ static inline void cdns_pcie_rp_writew(struct
> cdns_pcie *pcie,
> > cdns_pcie_write_sz(addr, 0x2, value); }
> >
> > +static inline u8 cdns_pcie_rp_readb(struct cdns_pcie *pcie, u32 reg)
> > +{
> > + return readb(pcie->reg_base + CDNS_PCIE_RP_BASE + reg); }
> > +
> > /* Endpoint Function register access */ static inline void
> > cdns_pcie_ep_fn_writeb(struct cdns_pcie *pcie, u8 fn,
> > u32 reg, u8 value)
> > --
> > 1.7.1
> >

2020-09-23 08:05:33

by Athani Nadeem Ladkhan

Subject: RE: [PATCH] PCI: Cadence: Add quirk for Gen2 controller to do autonomous speed change.

> -----Original Message-----
> From: Rob Herring <[email protected]>
> Sent: Tuesday, September 22, 2020 11:08 PM
> To: Athani Nadeem Ladkhan <[email protected]>
> Cc: Tom Joseph <[email protected]>; Lorenzo Pieralisi
> <[email protected]>; Bjorn Helgaas <[email protected]>; PCI
> <[email protected]>; [email protected]; Milind Parab
> <[email protected]>; Swapnil Kashinath Jakhade
> <[email protected]>
> Subject: Re: [PATCH] PCI: Cadence: Add quirk for Gen2 controller to do
> autonomous speed change.
>
> EXTERNAL MAIL
>
>
> On Fri, Sep 18, 2020 at 4:34 AM Nadeem Athani <[email protected]>
> wrote:
> >
> > Cadence controller will not initiate autonomous speed change if
> > strapped as Gen2. The Retrain bit is set as a quirk to trigger this
> > speed change.
> >
> > Signed-off-by: Nadeem Athani <[email protected]>
> > ---
> > drivers/pci/controller/cadence/pcie-cadence-host.c | 13 +++++++++++++
> > drivers/pci/controller/cadence/pcie-cadence.h | 6 ++++++
> > 2 files changed, 19 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c
> > b/drivers/pci/controller/cadence/pcie-cadence-host.c
> > index 4550e0d..4cb7f29 100644
> > --- a/drivers/pci/controller/cadence/pcie-cadence-host.c
> > +++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
> > @@ -83,6 +83,8 @@ static int cdns_pcie_host_init_root_port(struct
> cdns_pcie_rc *rc)
> > struct cdns_pcie *pcie = &rc->pcie;
> > u32 value, ctrl;
> > u32 id;
> > + u32 link_cap = CDNS_PCIE_LINK_CAP_OFFSET;
> > + u8 sls, lnk_ctl;
> >
> > /*
> > * Set the root complex BAR configuration register:
> > @@ -111,6 +113,17 @@ static int cdns_pcie_host_init_root_port(struct
> cdns_pcie_rc *rc)
> > if (rc->device_id != 0xffff)
> > cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID,
> > rc->device_id);
> >
> > + /* Quirk to enable autonomous speed change for GEN2 controller */
> > + /* Reading Supported Link Speed value */
> > + sls = PCI_EXP_LNKCAP_SLS &
> > + cdns_pcie_rp_readb(pcie, link_cap + PCI_EXP_LNKCAP);
> > + if (sls == PCI_EXP_LNKCAP_SLS_5_0GB) {
> > + /* Since this a Gen2 controller, set Retrain Link(RL) bit */
> > + lnk_ctl = cdns_pcie_rp_readb(pcie, link_cap + PCI_EXP_LNKCTL);
> > + lnk_ctl |= PCI_EXP_LNKCTL_RL;
> > + cdns_pcie_rp_writeb(pcie, link_cap + PCI_EXP_LNKCTL,
> > + lnk_ctl);
>
> Why the byte accesses? This is a 16-bit register.
> This is a 32bit register. But the register field require is at first byte only. Hence the byte access.
> > + }
> > +
> > cdns_pcie_rp_writeb(pcie, PCI_CLASS_REVISION, 0);
> > cdns_pcie_rp_writeb(pcie, PCI_CLASS_PROG, 0);
> > cdns_pcie_rp_writew(pcie, PCI_CLASS_DEVICE,
> > PCI_CLASS_BRIDGE_PCI); diff --git
> > a/drivers/pci/controller/cadence/pcie-cadence.h
> > b/drivers/pci/controller/cadence/pcie-cadence.h
> > index feed1e3..075c263 100644
> > --- a/drivers/pci/controller/cadence/pcie-cadence.h
> > +++ b/drivers/pci/controller/cadence/pcie-cadence.h
> > @@ -120,6 +120,7 @@
> > */
> > #define CDNS_PCIE_RP_BASE 0x00200000
> >
> > +#define CDNS_PCIE_LINK_CAP_OFFSET 0xC0
> >
> > /*
> > * Address Translation Registers
> > @@ -413,6 +414,11 @@ static inline void cdns_pcie_rp_writew(struct
> cdns_pcie *pcie,
> > cdns_pcie_write_sz(addr, 0x2, value); }
> >
> > +static inline u8 cdns_pcie_rp_readb(struct cdns_pcie *pcie, u32 reg)
> > +{
> > + return readb(pcie->reg_base + CDNS_PCIE_RP_BASE + reg); }
> > +
> > /* Endpoint Function register access */ static inline void
> > cdns_pcie_ep_fn_writeb(struct cdns_pcie *pcie, u8 fn,
> > u32 reg, u8 value)
> > --
> > 1.7.1
> >

2020-09-23 14:15:39

by Rob Herring (Arm)

Subject: Re: [PATCH] PCI: Cadence: Add quirk for Gen2 controller to do autonomous speed change.

On Wed, Sep 23, 2020 at 1:54 AM Athani Nadeem Ladkhan
<[email protected]> wrote:
>
> Hi Rob,
>
> > -----Original Message-----
> > From: Rob Herring <[email protected]>
> > Sent: Tuesday, September 22, 2020 11:08 PM
> > To: Athani Nadeem Ladkhan <[email protected]>
> > Cc: Tom Joseph <[email protected]>; Lorenzo Pieralisi
> > <[email protected]>; Bjorn Helgaas <[email protected]>; PCI
> > <[email protected]>; [email protected]; Milind Parab
> > <[email protected]>; Swapnil Kashinath Jakhade
> > <[email protected]>
> > Subject: Re: [PATCH] PCI: Cadence: Add quirk for Gen2 controller to do
> > autonomous speed change.
> >
> > EXTERNAL MAIL
> >
> >
> > On Fri, Sep 18, 2020 at 4:34 AM Nadeem Athani <[email protected]>
> > wrote:
> > >
> > > Cadence controller will not initiate autonomous speed change if
> > > strapped as Gen2. The Retrain bit is set as a quirk to trigger this
> > > speed change.
> > >
> > > Signed-off-by: Nadeem Athani <[email protected]>
> > > ---
> > > drivers/pci/controller/cadence/pcie-cadence-host.c | 13 +++++++++++++
> > > drivers/pci/controller/cadence/pcie-cadence.h | 6 ++++++
> > > 2 files changed, 19 insertions(+), 0 deletions(-)
> > >
> > > diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c
> > > b/drivers/pci/controller/cadence/pcie-cadence-host.c
> > > index 4550e0d..4cb7f29 100644
> > > --- a/drivers/pci/controller/cadence/pcie-cadence-host.c
> > > +++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
> > > @@ -83,6 +83,8 @@ static int cdns_pcie_host_init_root_port(struct
> > cdns_pcie_rc *rc)
> > > struct cdns_pcie *pcie = &rc->pcie;
> > > u32 value, ctrl;
> > > u32 id;
> > > + u32 link_cap = CDNS_PCIE_LINK_CAP_OFFSET;
> > > + u8 sls, lnk_ctl;
> > >
> > > /*
> > > * Set the root complex BAR configuration register:
> > > @@ -111,6 +113,17 @@ static int cdns_pcie_host_init_root_port(struct
> > cdns_pcie_rc *rc)
> > > if (rc->device_id != 0xffff)
> > > cdns_pcie_rp_writew(pcie, PCI_DEVICE_ID,
> > > rc->device_id);
> > >
> > > + /* Quirk to enable autonomous speed change for GEN2 controller */
> > > + /* Reading Supported Link Speed value */
> > > + sls = PCI_EXP_LNKCAP_SLS &
> > > + cdns_pcie_rp_readb(pcie, link_cap + PCI_EXP_LNKCAP);
> > > + if (sls == PCI_EXP_LNKCAP_SLS_5_0GB) {
> > > + /* Since this a Gen2 controller, set Retrain Link(RL) bit */
> > > + lnk_ctl = cdns_pcie_rp_readb(pcie, link_cap + PCI_EXP_LNKCTL);
> > > + lnk_ctl |= PCI_EXP_LNKCTL_RL;
> > > + cdns_pcie_rp_writeb(pcie, link_cap + PCI_EXP_LNKCTL,
> > > + lnk_ctl);
> >
> > Why the byte accesses? This is a 16-bit register.
> This is a 32bit register. But the register field require is at first byte only. Hence the byte access.

No, it's a 16-bit register as Link Status is at the next half word:

#define PCI_EXP_LNKCTL 16 /* Link Control */
#define PCI_EXP_LNKSTA 18 /* Link Status */

Use accesses that match the register size.

Rob