From 4740b969aaf58adeca6829947a3ad8da423976cf Mon Sep 17 00:00:00 2001 From: Nadeem Athani Date: Tue, 9 Feb 2021 15:46:21 +0100 Subject: PCI: cadence: Retrain Link to work around Gen2 training defect 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. Link: https://lore.kernel.org/r/20210209144622.26683-3-nadeem@cadence.com Signed-off-by: Nadeem Athani Signed-off-by: Lorenzo Pieralisi --- drivers/pci/controller/cadence/pcie-cadence-host.c | 81 +++++++++++++++++----- 1 file changed, 63 insertions(+), 18 deletions(-) (limited to 'drivers/pci/controller/cadence/pcie-cadence-host.c') diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c index 811c1cb2e8de..6f591d382578 100644 --- a/drivers/pci/controller/cadence/pcie-cadence-host.c +++ b/drivers/pci/controller/cadence/pcie-cadence-host.c @@ -77,6 +77,68 @@ static struct pci_ops cdns_pcie_host_ops = { .write = pci_generic_config_write, }; +static int cdns_pcie_host_wait_for_link(struct cdns_pcie *pcie) +{ + struct device *dev = pcie->dev; + int retries; + + /* Check if the link is up or not */ + for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) { + if (cdns_pcie_link_up(pcie)) { + dev_info(dev, "Link up\n"); + return 0; + } + usleep_range(LINK_WAIT_USLEEP_MIN, LINK_WAIT_USLEEP_MAX); + } + + return -ETIMEDOUT; +} + +static int cdns_pcie_retrain(struct cdns_pcie *pcie) +{ + u32 lnk_cap_sls, pcie_cap_off = CDNS_PCIE_RP_CAP_OFFSET; + u16 lnk_stat, lnk_ctl; + int ret = 0; + + /* + * 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 ret; + + 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); + + ret = cdns_pcie_host_wait_for_link(pcie); + } + return ret; +} + +static int cdns_pcie_host_start_link(struct cdns_pcie_rc *rc) +{ + struct cdns_pcie *pcie = &rc->pcie; + int ret; + + ret = cdns_pcie_host_wait_for_link(pcie); + + /* + * Retrain link for Gen2 training defect + * if quirk flag is set. + */ + if (!ret && rc->quirk_retrain_flag) + ret = cdns_pcie_retrain(pcie); + + return ret; +} static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc) { @@ -398,23 +460,6 @@ static int cdns_pcie_host_init(struct device *dev, return cdns_pcie_host_init_address_translation(rc); } -static int cdns_pcie_host_wait_for_link(struct cdns_pcie *pcie) -{ - struct device *dev = pcie->dev; - int retries; - - /* Check if the link is up or not */ - for (retries = 0; retries < LINK_WAIT_MAX_RETRIES; retries++) { - if (cdns_pcie_link_up(pcie)) { - dev_info(dev, "Link up\n"); - return 0; - } - usleep_range(LINK_WAIT_USLEEP_MIN, LINK_WAIT_USLEEP_MAX); - } - - return -ETIMEDOUT; -} - int cdns_pcie_host_setup(struct cdns_pcie_rc *rc) { struct device *dev = rc->pcie.dev; @@ -457,7 +502,7 @@ int cdns_pcie_host_setup(struct cdns_pcie_rc *rc) return ret; } - ret = cdns_pcie_host_wait_for_link(pcie); + ret = cdns_pcie_host_start_link(rc); if (ret) dev_dbg(dev, "PCIe link never came up\n"); -- cgit From 1002573ee33efef0988a9a546c075a9fa37d2498 Mon Sep 17 00:00:00 2001 From: Krzysztof Wilczyński Date: Tue, 16 Feb 2021 20:59:35 +0000 Subject: PCI: cadence: Fix DMA range mapping early return error MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Function cdns_pcie_host_map_dma_ranges() iterates over a PCIe host bridge DMA ranges using the resource_list_for_each_entry() iterator, returning an error if cdns_pcie_host_bar_config() fails. 49e427e6bdd1 ("Merge branch 'pci/host-probe-refactor'") botched a merge so it *always* returned after the first DMA range, even if no error occurred. Fix the error checking so we return early only when an error occurs. [bhelgaas: commit log] Fixes: 49e427e6bdd1 ("Merge branch 'pci/host-probe-refactor'") Link: https://lore.kernel.org/r/20210216205935.3112661-1-kw@linux.com Signed-off-by: Krzysztof Wilczyński Signed-off-by: Bjorn Helgaas --- drivers/pci/controller/cadence/pcie-cadence-host.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers/pci/controller/cadence/pcie-cadence-host.c') diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/drivers/pci/controller/cadence/pcie-cadence-host.c index 811c1cb2e8de..1cb7cfc75d6e 100644 --- a/drivers/pci/controller/cadence/pcie-cadence-host.c +++ b/drivers/pci/controller/cadence/pcie-cadence-host.c @@ -321,9 +321,10 @@ static int cdns_pcie_host_map_dma_ranges(struct cdns_pcie_rc *rc) resource_list_for_each_entry(entry, &bridge->dma_ranges) { err = cdns_pcie_host_bar_config(rc, entry); - if (err) + if (err) { dev_err(dev, "Fail to configure IB using dma-ranges\n"); - return err; + return err; + } } return 0; -- cgit