From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967640AbeCAK5p (ORCPT ); Thu, 1 Mar 2018 05:57:45 -0500 Received: from mx2.suse.de ([195.135.220.15]:42833 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967523AbeCAK5k (ORCPT ); Thu, 1 Mar 2018 05:57:40 -0500 Date: Thu, 1 Mar 2018 11:57:37 +0100 From: Jean Delvare To: Guenter Roeck Cc: Wolfram Sang , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] i2c: piix4: Use request_muxed_region Message-ID: <20180301115737.5aa2288f@endymion> In-Reply-To: <1519678013-32749-2-git-send-email-linux@roeck-us.net> References: <1519678013-32749-1-git-send-email-linux@roeck-us.net> <1519678013-32749-2-git-send-email-linux@roeck-us.net> Organization: SUSE Linux X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.31; x86_64-suse-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 26 Feb 2018 12:46:53 -0800, Guenter Roeck wrote: > Accesses to SB800_PIIX4_SMB_IDX can occur from multiple drivers. > One example for another driver is the sp5100_tco driver. > > Use request_muxed_region() to ensure synchronization. > > Signed-off-by: Guenter Roeck > --- > v2: Dropped now unnecessary include of linux/mutex.h > Added error message if request_muxed_region() fails > Spell out affected driver in commit message > > Note that I did not try to do a performance analysis. > Doing so seemed excessive, even more so in the context of > piix4_imc_sleep() already using request_muxed_region(). > > drivers/i2c/busses/i2c-piix4.c | 55 +++++++++++++++++++----------------------- > 1 file changed, 25 insertions(+), 30 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c > index 4c1f6aaec0fc..90946a8b9a75 100644 > --- a/drivers/i2c/busses/i2c-piix4.c > +++ b/drivers/i2c/busses/i2c-piix4.c > @@ -40,7 +40,6 @@ > #include > #include > #include > -#include > > > /* PIIX4 SMBus address offsets */ > @@ -153,10 +152,7 @@ static const struct dmi_system_id piix4_dmi_ibm[] = { > > /* > * SB800 globals > - * piix4_mutex_sb800 protects piix4_port_sel_sb800 and the pair > - * of I/O ports at SB800_PIIX4_SMB_IDX. > */ > -static DEFINE_MUTEX(piix4_mutex_sb800); > static u8 piix4_port_sel_sb800; > static u8 piix4_port_mask_sb800; > static u8 piix4_port_shift_sb800; > @@ -298,12 +294,19 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev, > else > smb_en = (aux) ? 0x28 : 0x2c; > > - mutex_lock(&piix4_mutex_sb800); > + if (!request_muxed_region(SB800_PIIX4_SMB_IDX, 2, "sb800_piix4_smb")) { > + dev_err(&PIIX4_dev->dev, > + "SMB base address index region 0x%x already in use.\n", > + SB800_PIIX4_SMB_IDX); > + return -EBUSY; > + } > + > outb_p(smb_en, SB800_PIIX4_SMB_IDX); > smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1); > outb_p(smb_en + 1, SB800_PIIX4_SMB_IDX); > smba_en_hi = inb_p(SB800_PIIX4_SMB_IDX + 1); > - mutex_unlock(&piix4_mutex_sb800); > + > + release_region(SB800_PIIX4_SMB_IDX, 2); > > if (!smb_en) { > smb_en_status = smba_en_lo & 0x10; > @@ -373,7 +376,12 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev, > break; > } > } else { > - mutex_lock(&piix4_mutex_sb800); > + if (!request_muxed_region(SB800_PIIX4_SMB_IDX, 2, > + "sb800_piix4_smb")) { > + release_region(piix4_smba, SMBIOSIZE); > + return -EBUSY; > + } > + > outb_p(SB800_PIIX4_PORT_IDX_SEL, SB800_PIIX4_SMB_IDX); > port_sel = inb_p(SB800_PIIX4_SMB_IDX + 1); > piix4_port_sel_sb800 = (port_sel & 0x01) ? > @@ -381,7 +389,7 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_dev, > SB800_PIIX4_PORT_IDX; > piix4_port_mask_sb800 = SB800_PIIX4_PORT_IDX_MASK; > piix4_port_shift_sb800 = SB800_PIIX4_PORT_IDX_SHIFT; > - mutex_unlock(&piix4_mutex_sb800); > + release_region(SB800_PIIX4_SMB_IDX, 2); > } > > dev_info(&PIIX4_dev->dev, > @@ -679,7 +687,8 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr, > u8 port; > int retval; > > - mutex_lock(&piix4_mutex_sb800); > + if (!request_muxed_region(SB800_PIIX4_SMB_IDX, 2, "sb800_piix4_smb")) > + return -EBUSY; > > /* Request the SMBUS semaphore, avoid conflicts with the IMC */ > smbslvcnt = inb_p(SMBSLVCNT); > @@ -695,8 +704,8 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr, > } while (--retries); > /* SMBus is still owned by the IMC, we give up */ > if (!retries) { > - mutex_unlock(&piix4_mutex_sb800); > - return -EBUSY; > + retval = -EBUSY; > + goto release; > } > > /* > @@ -753,8 +762,8 @@ static s32 piix4_access_sb800(struct i2c_adapter *adap, u16 addr, > if ((size == I2C_SMBUS_BLOCK_DATA) && adapdata->notify_imc) > piix4_imc_wakeup(); > > - mutex_unlock(&piix4_mutex_sb800); > - > +release: > + release_region(SB800_PIIX4_SMB_IDX, 2); > return retval; > } > > @@ -899,13 +908,6 @@ static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id) > bool notify_imc = false; > is_sb800 = true; > > - if (!request_region(SB800_PIIX4_SMB_IDX, 2, "smba_idx")) { > - dev_err(&dev->dev, > - "SMBus base address index region 0x%x already in use!\n", > - SB800_PIIX4_SMB_IDX); > - return -EBUSY; > - } > - > if (dev->vendor == PCI_VENDOR_ID_AMD && > dev->device == PCI_DEVICE_ID_AMD_KERNCZ_SMBUS) { > u8 imc; > @@ -922,20 +924,16 @@ static int piix4_probe(struct pci_dev *dev, const struct pci_device_id *id) > > /* base address location etc changed in SB800 */ > retval = piix4_setup_sb800(dev, id, 0); > - if (retval < 0) { > - release_region(SB800_PIIX4_SMB_IDX, 2); > + if (retval < 0) > return retval; > - } > > /* > * Try to register multiplexed main SMBus adapter, > * give up if we can't > */ > retval = piix4_add_adapters_sb800(dev, retval, notify_imc); > - if (retval < 0) { > - release_region(SB800_PIIX4_SMB_IDX, 2); > + if (retval < 0) > return retval; > - } > } else { > retval = piix4_setup(dev, id); > if (retval < 0) > @@ -983,11 +981,8 @@ static void piix4_adap_remove(struct i2c_adapter *adap) > > if (adapdata->smba) { > i2c_del_adapter(adap); > - if (adapdata->port == (0 << piix4_port_shift_sb800)) { > + if (adapdata->port == (0 << piix4_port_shift_sb800)) > release_region(adapdata->smba, SMBIOSIZE); > - if (adapdata->sb800_main) > - release_region(SB800_PIIX4_SMB_IDX, 2); > - } > kfree(adapdata); > kfree(adap); > } Reviewed-by: Jean Delvare -- Jean Delvare SUSE L3 Support