| Message ID | 20200918103429.4769-1-nadeem@cadence.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Delegated to: | Lorenzo Pieralisi |
| Headers | show |
| Series | PCI: Cadence: Add quirk for Gen2 controller to do autonomous speed change. | expand |
On Fri, Sep 18, 2020 at 4:34 AM Nadeem Athani <nadeem@cadence.com> 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 <nadeem@cadence.com> > --- > 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 >
> -----Original Message----- > From: Rob Herring <robh@kernel.org> > Sent: Tuesday, September 22, 2020 11:08 PM > To: Athani Nadeem Ladkhan <nadeem@cadence.com> > Cc: Tom Joseph <tjoseph@cadence.com>; Lorenzo Pieralisi > <lorenzo.pieralisi@arm.com>; Bjorn Helgaas <bhelgaas@google.com>; PCI > <linux-pci@vger.kernel.org>; linux-kernel@vger.kernel.org; Milind Parab > <mparab@cadence.com>; Swapnil Kashinath Jakhade > <sjakhade@cadence.com> > 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 <nadeem@cadence.com> > 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 <nadeem@cadence.com> > > --- > > 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 > >
Hi Rob, > -----Original Message----- > From: Rob Herring <robh@kernel.org> > Sent: Tuesday, September 22, 2020 11:08 PM > To: Athani Nadeem Ladkhan <nadeem@cadence.com> > Cc: Tom Joseph <tjoseph@cadence.com>; Lorenzo Pieralisi > <lorenzo.pieralisi@arm.com>; Bjorn Helgaas <bhelgaas@google.com>; PCI > <linux-pci@vger.kernel.org>; linux-kernel@vger.kernel.org; Milind Parab > <mparab@cadence.com>; Swapnil Kashinath Jakhade > <sjakhade@cadence.com> > 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 <nadeem@cadence.com> > 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 <nadeem@cadence.com> > > --- > > 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 > >
On Wed, Sep 23, 2020 at 1:54 AM Athani Nadeem Ladkhan <nadeem@cadence.com> wrote: > > Hi Rob, > > > -----Original Message----- > > From: Rob Herring <robh@kernel.org> > > Sent: Tuesday, September 22, 2020 11:08 PM > > To: Athani Nadeem Ladkhan <nadeem@cadence.com> > > Cc: Tom Joseph <tjoseph@cadence.com>; Lorenzo Pieralisi > > <lorenzo.pieralisi@arm.com>; Bjorn Helgaas <bhelgaas@google.com>; PCI > > <linux-pci@vger.kernel.org>; linux-kernel@vger.kernel.org; Milind Parab > > <mparab@cadence.com>; Swapnil Kashinath Jakhade > > <sjakhade@cadence.com> > > 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 <nadeem@cadence.com> > > 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 <nadeem@cadence.com> > > > --- > > > 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
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)
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 <nadeem@cadence.com> --- drivers/pci/controller/cadence/pcie-cadence-host.c | 13 +++++++++++++ drivers/pci/controller/cadence/pcie-cadence.h | 6 ++++++ 2 files changed, 19 insertions(+), 0 deletions(-)