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 14:07:49 +0530 Message-ID: <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> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <56968EA6.2060408@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 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. 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 14:07:49 +0530 Subject: [PATCH v2 3/3] pci: dra7xx: use pdata callbacks to perform reset In-Reply-To: <56968EA6.2060408@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> Message-ID: <56975E5D.50603@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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. 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 S1752376AbcANIia (ORCPT ); Thu, 14 Jan 2016 03:38:30 -0500 Received: from devils.ext.ti.com ([198.47.26.153]:33535 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750807AbcANIi3 (ORCPT ); Thu, 14 Jan 2016 03:38:29 -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> CC: Russell King , , , , From: Kishon Vijay Abraham I Message-ID: <56975E5D.50603@ti.com> Date: Thu, 14 Jan 2016 14:07:49 +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: <56968EA6.2060408@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 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. Thanks Kishon