From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Date: Thu, 16 Aug 2018 14:57:08 +0530 From: poza@codeaurora.org To: Jon Derrick Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Bjorn Helgaas , Keith Busch , Sinan Kaya , Dongdong Liu Subject: Re: [PATCH 1/2] PCI/DPC: Add 'nodpc' parameter In-Reply-To: <1534368400-2807-1-git-send-email-jonathan.derrick@intel.com> References: <1534368400-2807-1-git-send-email-jonathan.derrick@intel.com> Message-ID: List-ID: On 2018-08-16 02:56, Jon Derrick wrote: > Some users may want to disable downstream port containment (DPC), so > give them this option > > Signed-off-by: Jon Derrick > --- > drivers/pci/pci.c | 2 ++ > drivers/pci/pci.h | 6 ++++++ > drivers/pci/pcie/dpc.c | 48 > ++++++++++++++++++++++++++++++++++++++---------- > include/linux/pci.h | 6 ++++++ > 4 files changed, 52 insertions(+), 10 deletions(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 80da484..4e629c2 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -6062,6 +6062,8 @@ static int __init pci_setup(char *str) > pcie_ats_disabled = true; > } else if (!strcmp(str, "noaer")) { > pci_no_aer(); > + } else if (!strcmp(str, "nodpc")) { > + pci_no_dpc(); > } else if (!strcmp(str, "earlydump")) { > pci_early_dump = true; > } else if (!strncmp(str, "realloc=", 8)) { > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h > index 6e0d152..f73f29e 100644 > --- a/drivers/pci/pci.h > +++ b/drivers/pci/pci.h > @@ -536,4 +536,10 @@ static inline void > pci_aer_clear_fatal_status(struct pci_dev *dev) { } > static inline void pci_aer_clear_device_status(struct pci_dev *dev) { > } > #endif > > +#ifdef CONFIG_PCIE_DPC > +void pci_no_dpc(void); > +#else > +static inline void pci_no_dpc(void) { } > +#endif > + > #endif /* DRIVERS_PCI_H */ > diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c > index f03279f..068fca0 100644 > --- a/drivers/pci/pcie/dpc.c > +++ b/drivers/pci/pcie/dpc.c > @@ -44,6 +44,18 @@ struct dpc_dev { > "Memory Request Completion Timeout", /* Bit Position 18 */ > }; > > +static int pcie_dpc_disable; > + > +void pci_no_dpc(void) > +{ > + pcie_dpc_disable = 1; > +} > + > +bool pci_dpc_available(void) > +{ > + return !pcie_dpc_disable && pci_aer_available() && pci_msi_enabled(); 1) why do you check pci_aer_available() ? 2) and pci_aer_available() already internally checks pci_msi_enabled(); > +} > + > static int dpc_wait_rp_inactive(struct dpc_dev *dpc) > { > unsigned long timeout = jiffies + HZ; > @@ -209,6 +221,17 @@ static irqreturn_t dpc_irq(int irq, void *context) > return IRQ_HANDLED; > } > > +static void dpc_disable(struct pci_dev *pdev) > +{ > + u16 cap_pos, ctl; > + > + cap_pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC); > + pci_read_config_word(pdev, cap_pos + PCI_EXP_DPC_CTL, &ctl); > + ctl &= ~(PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_EN_NONFATAL | > + PCI_EXP_DPC_CTL_INT_EN); > + pci_write_config_word(pdev, cap_pos + PCI_EXP_DPC_CTL, ctl); > +} > + > #define FLAG(x, y) (((x) & (y)) ? '+' : '-') > static int dpc_probe(struct pcie_device *dev) > { > @@ -221,9 +244,16 @@ static int dpc_probe(struct pcie_device *dev) > if (pcie_aer_get_firmware_first(pdev)) > return -ENOTSUPP; > > + if (!pci_dpc_available()) { > + status = -ENOTSUPP; > + goto disable_dpc; > + } > + > dpc = devm_kzalloc(device, sizeof(*dpc), GFP_KERNEL); > - if (!dpc) > - return -ENOMEM; > + if (!dpc) { > + status = -ENOMEM; > + goto disable_dpc; > + } > > dpc->cap_pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC); > dpc->dev = dev; > @@ -235,7 +265,7 @@ static int dpc_probe(struct pcie_device *dev) > if (status) { > dev_warn(device, "request IRQ%d failed: %d\n", dev->irq, > status); > - return status; > + goto disable_dpc; > } > > pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CAP, &cap); > @@ -260,17 +290,15 @@ static int dpc_probe(struct pcie_device *dev) > FLAG(cap, PCI_EXP_DPC_CAP_SW_TRIGGER), dpc->rp_log_size, > FLAG(cap, PCI_EXP_DPC_CAP_DL_ACTIVE)); > return status; > + > +disable_dpc: > + dpc_disable(pdev); > + return status; > } > > static void dpc_remove(struct pcie_device *dev) > { > - struct dpc_dev *dpc = get_service_data(dev); > - struct pci_dev *pdev = dev->port; > - u16 ctl; > - > - pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, &ctl); > - ctl &= ~(PCI_EXP_DPC_CTL_EN_FATAL | PCI_EXP_DPC_CTL_INT_EN); > - pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl); > + dpc_disable(dev->port); > } > > static struct pcie_port_service_driver dpcdriver = { > diff --git a/include/linux/pci.h b/include/linux/pci.h > index 5454e6b..559b792 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1473,6 +1473,12 @@ static inline int pci_irqd_intx_xlate(struct > irq_domain *d, > static inline bool pci_aer_available(void) { return false; } > #endif > > +#ifdef CONFIG_PCIE_DPC > +bool pci_dpc_available(void); > +#else > +static inline bool pci_dpc_available(void) { return false; } > +#endif > + > #ifdef CONFIG_PCIE_ECRC > void pcie_set_ecrc_checking(struct pci_dev *dev); > void pcie_ecrc_get_policy(char *str);