From patchwork Tue Oct 5 18:09:48 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Marek_Beh=C3=BAn?= X-Patchwork-Id: 12537467 X-Patchwork-Delegate: lorenzo.pieralisi@arm.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9A43C433EF for ; Tue, 5 Oct 2021 18:10:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CFED460F6C for ; Tue, 5 Oct 2021 18:10:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234447AbhJESL7 (ORCPT ); Tue, 5 Oct 2021 14:11:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:39248 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234632AbhJESL7 (ORCPT ); Tue, 5 Oct 2021 14:11:59 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 70ACA6115B; Tue, 5 Oct 2021 18:10:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1633457408; bh=XRWTS9jfPVzNNBmZWDyD304RTTJU12al2/+nn7eOtyU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pbBk1jmmXYeObxtelrWU/GePAWEBgU5KKX23zIMeoGzuArkeefxgA/oQxidwODFex JSLhIyd3mmnp+hnjydA1PNQJ5H9HnizKJYDU4I7OKw6tbe0IE389+R4SmbC8wru7Wi Dtg1rtxp+3Z4q2zIZaKmitCPtpSoUM3usuxV8GtVpfKTYHZBeMuWSVAulwuaZ0YP23 rfu6yMnnZpvu4Zrw+R3qTaprek/8a3pG6qFUbK/f2fGXOZE2KyaZHXtW4nGIjcew50 C8KTSDPxz1LxnhPPJysiMasB57AijZPGcJiZFSwU2iVJX5sFEGteuLieI2E7IOaSEO p8b8i9jehSK2Q== From: =?utf-8?q?Marek_Beh=C3=BAn?= To: Lorenzo Pieralisi Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, pali@kernel.org, =?utf-8?q?Marek_Beh=C3=BAn?= Subject: [PATCH v2 09/13] PCI: aardvark: Implement re-issuing config requests on CRS response Date: Tue, 5 Oct 2021 20:09:48 +0200 Message-Id: <20211005180952.6812-10-kabel@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211005180952.6812-1-kabel@kernel.org> References: <20211005180952.6812-1-kabel@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Pali Rohár Commit 43f5c77bcbd2 ("PCI: aardvark: Fix reporting CRS value") fixed handling of CRS response and when CRSSVE flag was not enabled it marked CRS response as failed transaction (due to simplicity). But pci-aardvark.c driver is already waiting up to the PIO_RETRY_CNT count for PIO config response and so we can with a small change implement re-issuing of config requests as described in PCIe base specification. This change implements re-issuing of config requests when response is CRS. Set upper bound of wait cycles to around PIO_RETRY_CNT, afterwards the transaction is marked as failed and an all-ones value is returned as before. We do this by returning appropriate error codes from function advk_pcie_check_pio_status(). On CRS we return -EAGAIN and caller then reissues transaction. Signed-off-by: Pali Rohár Reviewed-by: Marek Behún Signed-off-by: Marek Behún --- drivers/pci/controller/pci-aardvark.c | 67 +++++++++++++++++---------- 1 file changed, 43 insertions(+), 24 deletions(-) diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index cd5be284789e..efe8b5f7bf8c 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -603,6 +603,7 @@ static int advk_pcie_check_pio_status(struct advk_pcie *pcie, bool allow_crs, u3 u32 reg; unsigned int status; char *strcomp_status, *str_posted; + int ret; reg = advk_readl(pcie, PIO_STAT); status = (reg & PIO_COMPLETION_STATUS_MASK) >> @@ -627,6 +628,7 @@ static int advk_pcie_check_pio_status(struct advk_pcie *pcie, bool allow_crs, u3 case PIO_COMPLETION_STATUS_OK: if (reg & PIO_ERR_STATUS) { strcomp_status = "COMP_ERR"; + ret = -EFAULT; break; } /* Get the read result */ @@ -634,9 +636,11 @@ static int advk_pcie_check_pio_status(struct advk_pcie *pcie, bool allow_crs, u3 *val = advk_readl(pcie, PIO_RD_DATA); /* No error */ strcomp_status = NULL; + ret = 0; break; case PIO_COMPLETION_STATUS_UR: strcomp_status = "UR"; + ret = -EOPNOTSUPP; break; case PIO_COMPLETION_STATUS_CRS: if (allow_crs && val) { @@ -654,6 +658,7 @@ static int advk_pcie_check_pio_status(struct advk_pcie *pcie, bool allow_crs, u3 */ *val = CFG_RD_CRS_VAL; strcomp_status = NULL; + ret = 0; break; } /* PCIe r4.0, sec 2.3.2, says: @@ -669,21 +674,24 @@ static int advk_pcie_check_pio_status(struct advk_pcie *pcie, bool allow_crs, u3 * Request and taking appropriate action, e.g., complete the * Request to the host as a failed transaction. * - * To simplify implementation do not re-issue the Configuration - * Request and complete the Request as a failed transaction. + * So return -EAGAIN and caller (pci-aardvark.c driver) will + * re-issue request again up to the PIO_RETRY_CNT retries. */ strcomp_status = "CRS"; + ret = -EAGAIN; break; case PIO_COMPLETION_STATUS_CA: strcomp_status = "CA"; + ret = -ECANCELED; break; default: strcomp_status = "Unknown"; + ret = -EINVAL; break; } if (!strcomp_status) - return 0; + return ret; if (reg & PIO_NON_POSTED_REQ) str_posted = "Non-posted"; @@ -693,7 +701,7 @@ static int advk_pcie_check_pio_status(struct advk_pcie *pcie, bool allow_crs, u3 dev_dbg(dev, "%s PIO Response Status: %s, %#x @ %#x\n", str_posted, strcomp_status, reg, advk_readl(pcie, PIO_ADDR_LS)); - return -EFAULT; + return ret; } static int advk_pcie_wait_pio(struct advk_pcie *pcie) @@ -701,13 +709,13 @@ static int advk_pcie_wait_pio(struct advk_pcie *pcie) struct device *dev = &pcie->pdev->dev; int i; - for (i = 0; i < PIO_RETRY_CNT; i++) { + for (i = 1; i <= PIO_RETRY_CNT; i++) { u32 start, isr; start = advk_readl(pcie, PIO_START); isr = advk_readl(pcie, PIO_ISR); if (!start && isr) - return 0; + return i; udelay(PIO_RETRY_DELAY); } @@ -898,6 +906,7 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn, int where, int size, u32 *val) { struct advk_pcie *pcie = bus->sysdata; + int retry_count; bool allow_crs; u32 reg; int ret; @@ -940,16 +949,22 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn, /* Program the data strobe */ advk_writel(pcie, 0xf, PIO_WR_DATA_STRB); - /* Clear PIO DONE ISR and start the transfer */ - advk_writel(pcie, 1, PIO_ISR); - advk_writel(pcie, 1, PIO_START); + retry_count = 0; + do { + /* Clear PIO DONE ISR and start the transfer */ + advk_writel(pcie, 1, PIO_ISR); + advk_writel(pcie, 1, PIO_START); - ret = advk_pcie_wait_pio(pcie); - if (ret < 0) - goto try_crs; + ret = advk_pcie_wait_pio(pcie); + if (ret < 0) + goto try_crs; + + retry_count += ret; + + /* Check PIO status and get the read result */ + ret = advk_pcie_check_pio_status(pcie, allow_crs, val); + } while (ret == -EAGAIN && retry_count < PIO_RETRY_CNT); - /* Check PIO status and get the read result */ - ret = advk_pcie_check_pio_status(pcie, allow_crs, val); if (ret < 0) goto fail; @@ -981,6 +996,7 @@ static int advk_pcie_wr_conf(struct pci_bus *bus, u32 devfn, struct advk_pcie *pcie = bus->sysdata; u32 reg; u32 data_strobe = 0x0; + int retry_count; int offset; int ret; @@ -1022,19 +1038,22 @@ static int advk_pcie_wr_conf(struct pci_bus *bus, u32 devfn, /* Program the data strobe */ advk_writel(pcie, data_strobe, PIO_WR_DATA_STRB); - /* Clear PIO DONE ISR and start the transfer */ - advk_writel(pcie, 1, PIO_ISR); - advk_writel(pcie, 1, PIO_START); + retry_count = 0; + do { + /* Clear PIO DONE ISR and start the transfer */ + advk_writel(pcie, 1, PIO_ISR); + advk_writel(pcie, 1, PIO_START); - ret = advk_pcie_wait_pio(pcie); - if (ret < 0) - return PCIBIOS_SET_FAILED; + ret = advk_pcie_wait_pio(pcie); + if (ret < 0) + return PCIBIOS_SET_FAILED; - ret = advk_pcie_check_pio_status(pcie, false, NULL); - if (ret < 0) - return PCIBIOS_SET_FAILED; + retry_count += ret; - return PCIBIOS_SUCCESSFUL; + ret = advk_pcie_check_pio_status(pcie, false, NULL); + } while (ret == -EAGAIN && retry_count < PIO_RETRY_CNT); + + return ret < 0 ? PCIBIOS_SET_FAILED : PCIBIOS_SUCCESSFUL; } static struct pci_ops advk_pcie_ops = {