From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH v2 2/2] i2c: piix4: Use request_muxed_region Date: Mon, 26 Feb 2018 21:52:04 +0100 Message-ID: <20180226205204.p37lf7dcl5k7az37@ninjato> References: <1519678013-32749-1-git-send-email-linux@roeck-us.net> <1519678013-32749-2-git-send-email-linux@roeck-us.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="l2qe2bydcixlr3um" Return-path: Content-Disposition: inline In-Reply-To: <1519678013-32749-2-git-send-email-linux@roeck-us.net> Sender: linux-kernel-owner@vger.kernel.org To: Guenter Roeck Cc: Jean Delvare , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-i2c@vger.kernel.org --l2qe2bydcixlr3um Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Feb 26, 2018 at 12:46:53PM -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. >=20 > Use request_muxed_region() to ensure synchronization. >=20 > Signed-off-by: Guenter Roeck To understand better: How does this relate to the series Zoltan Boszormenyi was proposing (in one sentence)? > --- > v2: Dropped now unnecessary include of linux/mutex.h > Added error message if request_muxed_region() fails > Spell out affected driver in commit message >=20 > 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().=20 >=20 > drivers/i2c/busses/i2c-piix4.c | 55 +++++++++++++++++++-----------------= ------ > 1 file changed, 25 insertions(+), 30 deletions(-) >=20 > diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix= 4.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 > =20 > =20 > /* PIIX4 SMBus address offsets */ > @@ -153,10 +152,7 @@ static const struct dmi_system_id piix4_dmi_ibm[] = =3D { > =20 > /* > * 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 =3D (aux) ? 0x28 : 0x2c; > =20 > - 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 =3D inb_p(SB800_PIIX4_SMB_IDX + 1); > outb_p(smb_en + 1, SB800_PIIX4_SMB_IDX); > smba_en_hi =3D inb_p(SB800_PIIX4_SMB_IDX + 1); > - mutex_unlock(&piix4_mutex_sb800); > + > + release_region(SB800_PIIX4_SMB_IDX, 2); > =20 > if (!smb_en) { > smb_en_status =3D smba_en_lo & 0x10; > @@ -373,7 +376,12 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_d= ev, > 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 =3D inb_p(SB800_PIIX4_SMB_IDX + 1); > piix4_port_sel_sb800 =3D (port_sel & 0x01) ? > @@ -381,7 +389,7 @@ static int piix4_setup_sb800(struct pci_dev *PIIX4_de= v, > SB800_PIIX4_PORT_IDX; > piix4_port_mask_sb800 =3D SB800_PIIX4_PORT_IDX_MASK; > piix4_port_shift_sb800 =3D SB800_PIIX4_PORT_IDX_SHIFT; > - mutex_unlock(&piix4_mutex_sb800); > + release_region(SB800_PIIX4_SMB_IDX, 2); > } > =20 > dev_info(&PIIX4_dev->dev, > @@ -679,7 +687,8 @@ static s32 piix4_access_sb800(struct i2c_adapter *ada= p, u16 addr, > u8 port; > int retval; > =20 > - mutex_lock(&piix4_mutex_sb800); > + if (!request_muxed_region(SB800_PIIX4_SMB_IDX, 2, "sb800_piix4_smb")) > + return -EBUSY; > =20 > /* Request the SMBUS semaphore, avoid conflicts with the IMC */ > smbslvcnt =3D inb_p(SMBSLVCNT); > @@ -695,8 +704,8 @@ static s32 piix4_access_sb800(struct i2c_adapter *ada= p, u16 addr, > } while (--retries); > /* SMBus is still owned by the IMC, we give up */ > if (!retries) { > - mutex_unlock(&piix4_mutex_sb800); > - return -EBUSY; > + retval =3D -EBUSY; > + goto release; > } > =20 > /* > @@ -753,8 +762,8 @@ static s32 piix4_access_sb800(struct i2c_adapter *ada= p, u16 addr, > if ((size =3D=3D I2C_SMBUS_BLOCK_DATA) && adapdata->notify_imc) > piix4_imc_wakeup(); > =20 > - mutex_unlock(&piix4_mutex_sb800); > - > +release: > + release_region(SB800_PIIX4_SMB_IDX, 2); > return retval; > } > =20 > @@ -899,13 +908,6 @@ static int piix4_probe(struct pci_dev *dev, const st= ruct pci_device_id *id) > bool notify_imc =3D false; > is_sb800 =3D true; > =20 > - 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 =3D=3D PCI_VENDOR_ID_AMD && > dev->device =3D=3D PCI_DEVICE_ID_AMD_KERNCZ_SMBUS) { > u8 imc; > @@ -922,20 +924,16 @@ static int piix4_probe(struct pci_dev *dev, const s= truct pci_device_id *id) > =20 > /* base address location etc changed in SB800 */ > retval =3D piix4_setup_sb800(dev, id, 0); > - if (retval < 0) { > - release_region(SB800_PIIX4_SMB_IDX, 2); > + if (retval < 0) > return retval; > - } > =20 > /* > * Try to register multiplexed main SMBus adapter, > * give up if we can't > */ > retval =3D 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 =3D piix4_setup(dev, id); > if (retval < 0) > @@ -983,11 +981,8 @@ static void piix4_adap_remove(struct i2c_adapter *ad= ap) > =20 > if (adapdata->smba) { > i2c_del_adapter(adap); > - if (adapdata->port =3D=3D (0 << piix4_port_shift_sb800)) { > + if (adapdata->port =3D=3D (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); > } > --=20 > 2.7.4 >=20 --l2qe2bydcixlr3um Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAlqUc3AACgkQFA3kzBSg KbYttBAAgaikolWwNix5wqLofJc62QPt7Qfn4QMS6IpYBDKSIqEYRSLcaotkI6aF /jjif9Hs+6S9ypfbypGH1BWvQtlMrbcj/DqZ0nUIxOsqcntoRvBOIfgJ/gQJ3XXc TD5Thgiai/YGpQQPxY1PJRw11FoS/qWngq4plftN2r/t7WxwSjHbTaIL7+tV5V/h MwURMwq0byFbBK/0qlMtSVUw8ZaT6wEoR9pVdJksywWrbqHT5vyFvpwQ68OOkm3c 0hI/XievMRsiDGyHSRybcSv//QV1FGvZs2P6ikVWsWS/A2r1UMitewq5BI3GzRtr Ojerm4aHb+14ToeXmGB/Idc6ppsFDvXQeckYVWNh05n+BZFq4OsM/GVh0CfPb6RG crgnq6ojc5JwSBEJkk3jncJtSUsC8KIEzmmbhiqJ8e4yXpSSp6uGdvnxNvW5B00F Of8YUj9DYOcKP8+Es8b3Y+KuHmUB0CvtfFMq8/FE+PdmMtvtN76b7BJTKYyOokCT 1ejGs1byLFvJ9zR2LkoPcJP4sn/pZg0WDhn0dL+bVt5h2Ix7vZHSur7duyRZhftA dXWvHZYeYHdNykCU6aYo5xDhuo/1d0iuTV0i5HsswqHTiiWEyppugPSNF6oX4kU+ Akdj+q+2nKCQg/MjLyNIqb30RQSx2tBkh0MtaElcTyRv4SENp8o= =CQ1L -----END PGP SIGNATURE----- --l2qe2bydcixlr3um--