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Wed, 24 Jul 2019 10:48:53 -0700 From: Vidya Sagar To: , , , , , , , , , , Subject: [PATCH V14 03/13] PCI: dwc: Perform dbi regs write lock towards the end Date: Wed, 24 Jul 2019 23:18:14 +0530 Message-ID: <20190724174824.20933-4-vidyas@nvidia.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190724174824.20933-1-vidyas@nvidia.com> References: <20190724174824.20933-1-vidyas@nvidia.com> X-NVConfidentiality: public MIME-Version: 1.0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1563990542; bh=pPgPGeFDk8dmm7wNOWblBUsUoR2+jLrVSQDaNueAWkQ=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:X-NVConfidentiality:MIME-Version: Content-Type; b=HXZibtPEcFFj/IogBRkmX4oRG2B9ROSoX5czdZyrPF76qYtql7H7YoausX0xO5gIu 5ELFJN++I+4B9xWAxK/K90RBS9LvtASZkUO+QooMmvYTenjINRJPeSYXTymiBpx5zM EuYxqSReY3CDDMfM77hiTcEkS8J0aXBEJb7nTijjA9iWS0pC07ubAd+8VeJ1B06Tzd mmYYdfwP1D8NrXie0JA/n7ipK8rzaTxOFriSjw+Lvbzf3sBGG93fhaI484aQZWmjF8 Rhu+i9llndPSedTjh7Mb91eRiOiLUFZ0g4CYTqBCOqTwhwrfS55qnNWqmw9cp4XkXv ccOz5hIwZmLzg== X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190724_104856_576668_73146F69 X-CRM114-Status: GOOD ( 10.11 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, mmaddireddy@nvidia.com, kthota@nvidia.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, mperttunen@nvidia.com, linux-tegra@vger.kernel.org, digetx@gmail.com, vidyas@nvidia.com, linux-arm-kernel@lists.infradead.org, sagar.tv@gmail.com Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Some of DesignWare core's DBI registers (a.k.a configuration space registers) are write-protected with a lock without enabling which they are read-only by default. These write-protected registers are implementation specific. Tegra194's BAR-0 register which is at offset 0x10 in the configuration space is an example. Current implementation in dw_pcie_setup_rc() API attempts to unlock those write-protected registers whenever they are updated and lock them back again for writing. This patch attempts to unlock all such write-protected registers for writing in the beginning of the API once and lock them back again towards the end to avoid bloating the API with multiple unlock/lock sequences for all those write-protected registers. Signed-off-by: Vidya Sagar Reviewed-by: Thierry Reding Acked-by: Jingoo Han --- V14: * None V13: * None V12: * Modified commit message to make it explicit that write-protected registers are implementation specific. V11: * None V10: * None V9: * None V8: * None V7: * None V6: * Moved write enable to the beginning of the API and write disable to the end V5: * None V4: * None V3: * None V2: * None drivers/pci/controller/dwc/pcie-designware-host.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c index f93252d0da5b..d3156446ff27 100644 --- a/drivers/pci/controller/dwc/pcie-designware-host.c +++ b/drivers/pci/controller/dwc/pcie-designware-host.c @@ -628,6 +628,12 @@ void dw_pcie_setup_rc(struct pcie_port *pp) u32 val, ctrl, num_ctrls; struct dw_pcie *pci = to_dw_pcie_from_pp(pp); + /* + * Enable DBI read-only registers for writing/updating configuration. + * Write permission gets disabled towards the end of this function. + */ + dw_pcie_dbi_ro_wr_en(pci); + dw_pcie_setup(pci); if (!pp->ops->msi_host_init) { @@ -650,12 +656,10 @@ void dw_pcie_setup_rc(struct pcie_port *pp) dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_1, 0x00000000); /* Setup interrupt pins */ - dw_pcie_dbi_ro_wr_en(pci); val = dw_pcie_readl_dbi(pci, PCI_INTERRUPT_LINE); val &= 0xffff00ff; val |= 0x00000100; dw_pcie_writel_dbi(pci, PCI_INTERRUPT_LINE, val); - dw_pcie_dbi_ro_wr_dis(pci); /* Setup bus numbers */ val = dw_pcie_readl_dbi(pci, PCI_PRIMARY_BUS); @@ -687,15 +691,13 @@ void dw_pcie_setup_rc(struct pcie_port *pp) dw_pcie_wr_own_conf(pp, PCI_BASE_ADDRESS_0, 4, 0); - /* Enable write permission for the DBI read-only register */ - dw_pcie_dbi_ro_wr_en(pci); /* Program correct class for RC */ dw_pcie_wr_own_conf(pp, PCI_CLASS_DEVICE, 2, PCI_CLASS_BRIDGE_PCI); - /* Better disable write permission right after the update */ - dw_pcie_dbi_ro_wr_dis(pci); dw_pcie_rd_own_conf(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, 4, &val); val |= PORT_LOGIC_SPEED_CHANGE; dw_pcie_wr_own_conf(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, 4, val); + + dw_pcie_dbi_ro_wr_dis(pci); } EXPORT_SYMBOL_GPL(dw_pcie_setup_rc);