From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kishon Vijay Abraham I Subject: Re: [PATCH v2 3/3] pci: dra7xx: use pdata callbacks to perform reset Date: Thu, 14 Jan 2016 18:58:25 +0530 Message-ID: <5697A279.3020506@ti.com> References: <1452667666-17533-1-git-send-email-kishon@ti.com> <1452667666-17533-4-git-send-email-kishon@ti.com> <56968EA6.2060408@ti.com> <56975E5D.50603@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <56975E5D.50603@ti.com> Sender: linux-kernel-owner@vger.kernel.org To: Suman Anna , Tony Lindgren , Bjorn Helgaas , richardcochran@gmail.com Cc: Russell King , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, nsekhar@ti.com List-Id: linux-omap@vger.kernel.org Hi, On Thursday 14 January 2016 02:07 PM, Kishon Vijay Abraham I wrote: > Hi Suman, > > On Wednesday 13 January 2016 11:21 PM, Suman Anna wrote: >> On 01/13/2016 12:47 AM, Kishon Vijay Abraham I wrote: >>> Use platform populated reset assert and deassert >>> callbacks to perform reset of PCIe. >>> >>> Use these callbacks until a reset interface using drivers/reset >>> is available for the purpose. >>> >>> Signed-off-by: Kishon Vijay Abraham I >>> Signed-off-by: Sekhar Nori >>> --- >>> drivers/pci/host/pci-dra7xx.c | 32 ++++++++++++++++++++++++++++++++ >>> 1 file changed, 32 insertions(+) >>> >>> diff --git a/drivers/pci/host/pci-dra7xx.c b/drivers/pci/host/pci-dra7xx.c >>> index 8c36880..049083d 100644 >>> --- a/drivers/pci/host/pci-dra7xx.c >>> +++ b/drivers/pci/host/pci-dra7xx.c >>> @@ -25,6 +25,8 @@ >>> #include >>> #include >>> >>> +#include >>> + >>> #include "pcie-designware.h" >>> >>> /* PCIe controller wrapper DRA7XX configuration registers */ >>> @@ -329,6 +331,32 @@ static int __init dra7xx_add_pcie_port(struct dra7xx_pcie *dra7xx, >>> return 0; >>> } >>> >>> +static int dra7xx_pcie_reset(struct platform_device *pdev) >>> +{ >>> + int ret; >>> + struct device *dev = &pdev->dev; >>> + struct pci_dra7xx_platform_data *pdata = pdev->dev.platform_data; >>> + >>> + if (!(pdata && pdata->deassert_reset && pdata->assert_reset)) { >>> + dev_err(dev, "platform data for reset not found!\n"); >>> + return -EINVAL; >>> + } >>> + >>> + ret = pdata->assert_reset(pdev, pdata->reset_name); >>> + if (ret) { >>> + dev_err(dev, "assert_reset failed: %d\n", ret); >>> + return ret; >>> + } >>> + >>> + ret = pdata->deassert_reset(pdev, pdata->reset_name); >>> + if (ret) { >>> + dev_err(dev, "deassert_reset failed: %d\n", ret); >>> + return ret; >>> + } >> >> The only comment I have on this is the symmetry (assert_reset invocation >> in driver remove). If you install and remove the module once, then the >> reset stays deasserted. On Power-On-Reset, the resets by default will be >> in asserted state. > > hmm.. not sure of the benefits of leaving the reset lines de-asserted during > remove. The idea is irrespective of the initial sate or power-on state, during > probe the driver should assert and de-assert the reset lines. Also right now the pci-dra7xx can't be inserted as a module. However since that might be added in the future, I'll add assert_reset in the remove path of this driver. Thanks Kishon From mboxrd@z Thu Jan 1 00:00:00 1970 From: kishon@ti.com (Kishon Vijay Abraham I) Date: Thu, 14 Jan 2016 18:58:25 +0530 Subject: [PATCH v2 3/3] pci: dra7xx: use pdata callbacks to perform reset In-Reply-To: <56975E5D.50603@ti.com> References: <1452667666-17533-1-git-send-email-kishon@ti.com> <1452667666-17533-4-git-send-email-kishon@ti.com> <56968EA6.2060408@ti.com> <56975E5D.50603@ti.com> Message-ID: <5697A279.3020506@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On Thursday 14 January 2016 02:07 PM, Kishon Vijay Abraham I wrote: > Hi Suman, > > On Wednesday 13 January 2016 11:21 PM, Suman Anna wrote: >> On 01/13/2016 12:47 AM, Kishon Vijay Abraham I wrote: >>> Use platform populated reset assert and deassert >>> callbacks to perform reset of PCIe. >>> >>> Use these callbacks until a reset interface using drivers/reset >>> is available for the purpose. >>> >>> Signed-off-by: Kishon Vijay Abraham I >>> Signed-off-by: Sekhar Nori >>> --- >>> drivers/pci/host/pci-dra7xx.c | 32 ++++++++++++++++++++++++++++++++ >>> 1 file changed, 32 insertions(+) >>> >>> diff --git a/drivers/pci/host/pci-dra7xx.c b/drivers/pci/host/pci-dra7xx.c >>> index 8c36880..049083d 100644 >>> --- a/drivers/pci/host/pci-dra7xx.c >>> +++ b/drivers/pci/host/pci-dra7xx.c >>> @@ -25,6 +25,8 @@ >>> #include >>> #include >>> >>> +#include >>> + >>> #include "pcie-designware.h" >>> >>> /* PCIe controller wrapper DRA7XX configuration registers */ >>> @@ -329,6 +331,32 @@ static int __init dra7xx_add_pcie_port(struct dra7xx_pcie *dra7xx, >>> return 0; >>> } >>> >>> +static int dra7xx_pcie_reset(struct platform_device *pdev) >>> +{ >>> + int ret; >>> + struct device *dev = &pdev->dev; >>> + struct pci_dra7xx_platform_data *pdata = pdev->dev.platform_data; >>> + >>> + if (!(pdata && pdata->deassert_reset && pdata->assert_reset)) { >>> + dev_err(dev, "platform data for reset not found!\n"); >>> + return -EINVAL; >>> + } >>> + >>> + ret = pdata->assert_reset(pdev, pdata->reset_name); >>> + if (ret) { >>> + dev_err(dev, "assert_reset failed: %d\n", ret); >>> + return ret; >>> + } >>> + >>> + ret = pdata->deassert_reset(pdev, pdata->reset_name); >>> + if (ret) { >>> + dev_err(dev, "deassert_reset failed: %d\n", ret); >>> + return ret; >>> + } >> >> The only comment I have on this is the symmetry (assert_reset invocation >> in driver remove). If you install and remove the module once, then the >> reset stays deasserted. On Power-On-Reset, the resets by default will be >> in asserted state. > > hmm.. not sure of the benefits of leaving the reset lines de-asserted during > remove. The idea is irrespective of the initial sate or power-on state, during > probe the driver should assert and de-assert the reset lines. Also right now the pci-dra7xx can't be inserted as a module. However since that might be added in the future, I'll add assert_reset in the remove path of this driver. Thanks Kishon From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754086AbcANN3F (ORCPT ); Thu, 14 Jan 2016 08:29:05 -0500 Received: from comal.ext.ti.com ([198.47.26.152]:50528 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752667AbcANN3D (ORCPT ); Thu, 14 Jan 2016 08:29:03 -0500 Subject: Re: [PATCH v2 3/3] pci: dra7xx: use pdata callbacks to perform reset To: Suman Anna , Tony Lindgren , Bjorn Helgaas , References: <1452667666-17533-1-git-send-email-kishon@ti.com> <1452667666-17533-4-git-send-email-kishon@ti.com> <56968EA6.2060408@ti.com> <56975E5D.50603@ti.com> CC: Russell King , , , , From: Kishon Vijay Abraham I Message-ID: <5697A279.3020506@ti.com> Date: Thu, 14 Jan 2016 18:58:25 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <56975E5D.50603@ti.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Thursday 14 January 2016 02:07 PM, Kishon Vijay Abraham I wrote: > Hi Suman, > > On Wednesday 13 January 2016 11:21 PM, Suman Anna wrote: >> On 01/13/2016 12:47 AM, Kishon Vijay Abraham I wrote: >>> Use platform populated reset assert and deassert >>> callbacks to perform reset of PCIe. >>> >>> Use these callbacks until a reset interface using drivers/reset >>> is available for the purpose. >>> >>> Signed-off-by: Kishon Vijay Abraham I >>> Signed-off-by: Sekhar Nori >>> --- >>> drivers/pci/host/pci-dra7xx.c | 32 ++++++++++++++++++++++++++++++++ >>> 1 file changed, 32 insertions(+) >>> >>> diff --git a/drivers/pci/host/pci-dra7xx.c b/drivers/pci/host/pci-dra7xx.c >>> index 8c36880..049083d 100644 >>> --- a/drivers/pci/host/pci-dra7xx.c >>> +++ b/drivers/pci/host/pci-dra7xx.c >>> @@ -25,6 +25,8 @@ >>> #include >>> #include >>> >>> +#include >>> + >>> #include "pcie-designware.h" >>> >>> /* PCIe controller wrapper DRA7XX configuration registers */ >>> @@ -329,6 +331,32 @@ static int __init dra7xx_add_pcie_port(struct dra7xx_pcie *dra7xx, >>> return 0; >>> } >>> >>> +static int dra7xx_pcie_reset(struct platform_device *pdev) >>> +{ >>> + int ret; >>> + struct device *dev = &pdev->dev; >>> + struct pci_dra7xx_platform_data *pdata = pdev->dev.platform_data; >>> + >>> + if (!(pdata && pdata->deassert_reset && pdata->assert_reset)) { >>> + dev_err(dev, "platform data for reset not found!\n"); >>> + return -EINVAL; >>> + } >>> + >>> + ret = pdata->assert_reset(pdev, pdata->reset_name); >>> + if (ret) { >>> + dev_err(dev, "assert_reset failed: %d\n", ret); >>> + return ret; >>> + } >>> + >>> + ret = pdata->deassert_reset(pdev, pdata->reset_name); >>> + if (ret) { >>> + dev_err(dev, "deassert_reset failed: %d\n", ret); >>> + return ret; >>> + } >> >> The only comment I have on this is the symmetry (assert_reset invocation >> in driver remove). If you install and remove the module once, then the >> reset stays deasserted. On Power-On-Reset, the resets by default will be >> in asserted state. > > hmm.. not sure of the benefits of leaving the reset lines de-asserted during > remove. The idea is irrespective of the initial sate or power-on state, during > probe the driver should assert and de-assert the reset lines. Also right now the pci-dra7xx can't be inserted as a module. However since that might be added in the future, I'll add assert_reset in the remove path of this driver. Thanks Kishon