From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753386AbdCPO4P (ORCPT ); Thu, 16 Mar 2017 10:56:15 -0400 Received: from foss.arm.com ([217.140.101.70]:35078 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753101AbdCPO4L (ORCPT ); Thu, 16 Mar 2017 10:56:11 -0400 Subject: Re: [PATCH] serial: 8250: 8250_core: Fix irq name for 8250 serial irq References: <20170316122653.19930-1-vigneshr@ti.com> <20170316133632.GV21222@n2100.armlinux.org.uk> To: Russell King - ARM Linux , Vignesh R Cc: Jisheng Zhang , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Andy Shevchenko , linux-serial@vger.kernel.org, Jiri Slaby , linux-arm-kernel@lists.infradead.org From: Robin Murphy Message-ID: <9a6dcf55-0ace-e617-73bc-0472a939b36c@arm.com> Date: Thu, 16 Mar 2017 14:55:18 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <20170316133632.GV21222@n2100.armlinux.org.uk> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 16/03/17 13:36, Russell King - ARM Linux wrote: > On Thu, Mar 16, 2017 at 05:56:53PM +0530, Vignesh R wrote: >> Using dev_name() as irq name during request_irq() might be misleading in >> case of serial over PCI. Therefore use a better alternative name for >> identifying serial port irqs as "serial" appended with serial_index of >> the port. This ensures that "serial" string is always present in irq >> name while port index will help in distinguishing b/w different ports. > > Wouldn't it be better to use the device name (iow, ttySx) rather than > "serialx" ? > > Maybe a helper function in serial_core.c to format the device name into > a supplied string, which can be re-used elsewhere, eg, uart_report_port() > and uart_suspend_port(). IOW: > > const char *uart_port_name(char *buf, size_t n, struct uart_driver *drv, > struct uart_port *port) > { > snprintf(buf, n, "%s%d", drv->dev_name, > drv->tty_driver->name_base + port->line); > > return buf; > } > > which means you can do this: > > char name[16]; > > request_irq(..., uart_port_name(name, sizeof(name), driver, port), ...) > > which also avoids the allocation. ...and makes 'cat /proc/interrupts' particularly fun later: 8: 0 GICv2 72 Level ��h ����V! Unless a suitably long-lived string already exists somewhere else in the serial core, the allocation is unavoidable, although kasprintf() (or its devm_ variant) might make matters a little simpler. Robin. > 8250 device names are always "ttyS" > plus a number, so 16 characters (including NULL terminator) should be > more than sufficient, and that's most likely true of all serial drivers. > (The longest device name I'm aware of is ttyAMA plus a small integer > for PL011 ports.) > From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [PATCH] serial: 8250: 8250_core: Fix irq name for 8250 serial irq Date: Thu, 16 Mar 2017 14:55:18 +0000 Message-ID: <9a6dcf55-0ace-e617-73bc-0472a939b36c@arm.com> References: <20170316122653.19930-1-vigneshr@ti.com> <20170316133632.GV21222@n2100.armlinux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <20170316133632.GV21222@n2100.armlinux.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Russell King - ARM Linux , Vignesh R Cc: Jisheng Zhang , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Andy Shevchenko , linux-serial@vger.kernel.org, Jiri Slaby , linux-arm-kernel@lists.infradead.org List-Id: linux-serial@vger.kernel.org T24gMTYvMDMvMTcgMTM6MzYsIFJ1c3NlbGwgS2luZyAtIEFSTSBMaW51eCB3cm90ZToKPiBPbiBU aHUsIE1hciAxNiwgMjAxNyBhdCAwNTo1Njo1M1BNICswNTMwLCBWaWduZXNoIFIgd3JvdGU6Cj4+ IFVzaW5nIGRldl9uYW1lKCkgYXMgaXJxIG5hbWUgZHVyaW5nIHJlcXVlc3RfaXJxKCkgbWlnaHQg YmUgbWlzbGVhZGluZyBpbgo+PiBjYXNlIG9mIHNlcmlhbCBvdmVyIFBDSS4gVGhlcmVmb3JlIHVz ZSBhIGJldHRlciBhbHRlcm5hdGl2ZSBuYW1lIGZvcgo+PiBpZGVudGlmeWluZyBzZXJpYWwgcG9y dCBpcnFzIGFzICJzZXJpYWwiIGFwcGVuZGVkIHdpdGggc2VyaWFsX2luZGV4IG9mCj4+IHRoZSBw b3J0LiBUaGlzIGVuc3VyZXMgdGhhdCAic2VyaWFsIiBzdHJpbmcgaXMgYWx3YXlzIHByZXNlbnQg aW4gaXJxCj4+IG5hbWUgd2hpbGUgcG9ydCBpbmRleCB3aWxsIGhlbHAgaW4gZGlzdGluZ3Vpc2hp bmcgYi93IGRpZmZlcmVudCBwb3J0cy4KPiAKPiBXb3VsZG4ndCBpdCBiZSBiZXR0ZXIgdG8gdXNl IHRoZSBkZXZpY2UgbmFtZSAoaW93LCB0dHlTeCkgcmF0aGVyIHRoYW4KPiAic2VyaWFseCIgPwo+ IAo+IE1heWJlIGEgaGVscGVyIGZ1bmN0aW9uIGluIHNlcmlhbF9jb3JlLmMgdG8gZm9ybWF0IHRo ZSBkZXZpY2UgbmFtZSBpbnRvCj4gYSBzdXBwbGllZCBzdHJpbmcsIHdoaWNoIGNhbiBiZSByZS11 c2VkIGVsc2V3aGVyZSwgZWcsIHVhcnRfcmVwb3J0X3BvcnQoKQo+IGFuZCB1YXJ0X3N1c3BlbmRf cG9ydCgpLiAgSU9XOgo+IAo+IGNvbnN0IGNoYXIgKnVhcnRfcG9ydF9uYW1lKGNoYXIgKmJ1Ziwg c2l6ZV90IG4sIHN0cnVjdCB1YXJ0X2RyaXZlciAqZHJ2LAo+IAkJCSAgIHN0cnVjdCB1YXJ0X3Bv cnQgKnBvcnQpCj4gewo+IAlzbnByaW50ZihidWYsIG4sICIlcyVkIiwgZHJ2LT5kZXZfbmFtZSwK PiAJCSBkcnYtPnR0eV9kcml2ZXItPm5hbWVfYmFzZSArIHBvcnQtPmxpbmUpOwo+IAo+IAlyZXR1 cm4gYnVmOwo+IH0KPiAKPiB3aGljaCBtZWFucyB5b3UgY2FuIGRvIHRoaXM6Cj4gCj4gCWNoYXIg bmFtZVsxNl07Cj4gCj4gCXJlcXVlc3RfaXJxKC4uLiwgdWFydF9wb3J0X25hbWUobmFtZSwgc2l6 ZW9mKG5hbWUpLCBkcml2ZXIsIHBvcnQpLCAuLi4pCj4gCj4gd2hpY2ggYWxzbyBhdm9pZHMgdGhl IGFsbG9jYXRpb24uCgouLi5hbmQgbWFrZXMgJ2NhdCAvcHJvYy9pbnRlcnJ1cHRzJyBwYXJ0aWN1 bGFybHkgZnVuIGxhdGVyOgoKICA4OiAgICAgICAgICAwICAgICAgICAgIEdJQ3YyICA3MiBMZXZl bCAgICAg77+9BO+/vWgJ77+977+977+977+9ViEKClVubGVzcyBhIHN1aXRhYmx5IGxvbmctbGl2 ZWQgc3RyaW5nIGFscmVhZHkgZXhpc3RzIHNvbWV3aGVyZSBlbHNlIGluIHRoZQpzZXJpYWwgY29y ZSwgdGhlIGFsbG9jYXRpb24gaXMgdW5hdm9pZGFibGUsIGFsdGhvdWdoIGthc3ByaW50ZigpIChv ciBpdHMKZGV2bV8gdmFyaWFudCkgbWlnaHQgbWFrZSBtYXR0ZXJzIGEgbGl0dGxlIHNpbXBsZXIu CgpSb2Jpbi4KCj4gIDgyNTAgZGV2aWNlIG5hbWVzIGFyZSBhbHdheXMgInR0eVMiCj4gcGx1cyBh IG51bWJlciwgc28gMTYgY2hhcmFjdGVycyAoaW5jbHVkaW5nIE5VTEwgdGVybWluYXRvcikgc2hv dWxkIGJlCj4gbW9yZSB0aGFuIHN1ZmZpY2llbnQsIGFuZCB0aGF0J3MgbW9zdCBsaWtlbHkgdHJ1 ZSBvZiBhbGwgc2VyaWFsIGRyaXZlcnMuCj4gKFRoZSBsb25nZXN0IGRldmljZSBuYW1lIEknbSBh d2FyZSBvZiBpcyB0dHlBTUEgcGx1cyBhIHNtYWxsIGludGVnZXIKPiBmb3IgUEwwMTEgcG9ydHMu KQo+IAoKCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCmxp bnV4LWFybS1rZXJuZWwgbWFpbGluZyBsaXN0CmxpbnV4LWFybS1rZXJuZWxAbGlzdHMuaW5mcmFk ZWFkLm9yZwpodHRwOi8vbGlzdHMuaW5mcmFkZWFkLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2xpbnV4 LWFybS1rZXJuZWwK From mboxrd@z Thu Jan 1 00:00:00 1970 From: robin.murphy@arm.com (Robin Murphy) Date: Thu, 16 Mar 2017 14:55:18 +0000 Subject: [PATCH] serial: 8250: 8250_core: Fix irq name for 8250 serial irq In-Reply-To: <20170316133632.GV21222@n2100.armlinux.org.uk> References: <20170316122653.19930-1-vigneshr@ti.com> <20170316133632.GV21222@n2100.armlinux.org.uk> Message-ID: <9a6dcf55-0ace-e617-73bc-0472a939b36c@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 16/03/17 13:36, Russell King - ARM Linux wrote: > On Thu, Mar 16, 2017 at 05:56:53PM +0530, Vignesh R wrote: >> Using dev_name() as irq name during request_irq() might be misleading in >> case of serial over PCI. Therefore use a better alternative name for >> identifying serial port irqs as "serial" appended with serial_index of >> the port. This ensures that "serial" string is always present in irq >> name while port index will help in distinguishing b/w different ports. > > Wouldn't it be better to use the device name (iow, ttySx) rather than > "serialx" ? > > Maybe a helper function in serial_core.c to format the device name into > a supplied string, which can be re-used elsewhere, eg, uart_report_port() > and uart_suspend_port(). IOW: > > const char *uart_port_name(char *buf, size_t n, struct uart_driver *drv, > struct uart_port *port) > { > snprintf(buf, n, "%s%d", drv->dev_name, > drv->tty_driver->name_base + port->line); > > return buf; > } > > which means you can do this: > > char name[16]; > > request_irq(..., uart_port_name(name, sizeof(name), driver, port), ...) > > which also avoids the allocation. ...and makes 'cat /proc/interrupts' particularly fun later: 8: 0 GICv2 72 Level ??h ????V! Unless a suitably long-lived string already exists somewhere else in the serial core, the allocation is unavoidable, although kasprintf() (or its devm_ variant) might make matters a little simpler. Robin. > 8250 device names are always "ttyS" > plus a number, so 16 characters (including NULL terminator) should be > more than sufficient, and that's most likely true of all serial drivers. > (The longest device name I'm aware of is ttyAMA plus a small integer > for PL011 ports.) >