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[23.128.96.18]) by mx.google.com with ESMTP id y22si1435086edv.198.2020.05.20.05.16.15; Wed, 20 May 2020 05:16:39 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726932AbgETMMJ (ORCPT + 99 others); Wed, 20 May 2020 08:12:09 -0400 Received: from mail.baikalelectronics.com ([87.245.175.226]:58300 "EHLO mail.baikalelectronics.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726452AbgETMMI (ORCPT ); Wed, 20 May 2020 08:12:08 -0400 Received: from localhost (unknown [127.0.0.1]) by mail.baikalelectronics.ru (Postfix) with ESMTP id 0FADA80307C1; Wed, 20 May 2020 12:12:03 +0000 (UTC) X-Virus-Scanned: amavisd-new at baikalelectronics.ru Received: from mail.baikalelectronics.ru ([127.0.0.1]) by localhost (mail.baikalelectronics.ru [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id c8BOnlAs7pZK; Wed, 20 May 2020 15:12:02 +0300 (MSK) Date: Wed, 20 May 2020 15:12:01 +0300 From: Serge Semin To: Thomas Bogendoerfer CC: Serge Semin , Alexey Malahov , Paul Burton , Ralf Baechle , Greg Kroah-Hartman , Arnd Bergmann , Rob Herring , , , Vincenzo Frascino , Thomas Gleixner , , Subject: Re: [PATCH v2 18/20] mips: csrc-r4k: Decrease r4k-clocksource rating if CPU_FREQ enabled Message-ID: <20200520121201.wohv6u646rx5otkf@mobilestation> References: <20200506174238.15385-1-Sergey.Semin@baikalelectronics.ru> <20200506174238.15385-19-Sergey.Semin@baikalelectronics.ru> <20200508154150.GB22247@alpha.franken.de> <20200511133121.cz5axbwynhmqkx7x@mobilestation> <20200515074827.6p5zx4sb3bmavjih@mobilestation> <20200515210647.GA22922@alpha.franken.de> <20200518134820.wedoumgbsllvhem6@mobilestation> <20200518163206.GA17800@alpha.franken.de> <20200518205752.txbylbjt2zkwdwwe@mobilestation> <20200519155053.GB15797@alpha.franken.de> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200519155053.GB15797@alpha.franken.de> X-ClientProxiedBy: MAIL.baikal.int (192.168.51.25) To mail (192.168.51.25) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 19, 2020 at 05:50:53PM +0200, Thomas Bogendoerfer wrote: > On Mon, May 18, 2020 at 11:57:52PM +0300, Serge Semin wrote: > > On Mon, May 18, 2020 at 06:32:06PM +0200, Thomas Bogendoerfer wrote: > > > On Mon, May 18, 2020 at 04:48:20PM +0300, Serge Semin wrote: > > > > On Fri, May 15, 2020 at 11:06:47PM +0200, Thomas Bogendoerfer wrote: > > > > > On Fri, May 15, 2020 at 10:48:27AM +0300, Serge Semin wrote: > > > > > > Thomas, > > > > > > Could you take a look at my comment below so I could proceed with the > > > > > > patchset v3 development? > > > > > > > > > > I can't help, but using r4k clocksource with changing frequency is > > > > > probaly only usefull as a random generator. So IMHO the only two > > > > > options are disabling it or implement what arch/x86/kernel/tsc.c does. > > > > > > > > > > Thomas. > > > > > > > > Thomas, could you proceed with the rest of the patches review? > > > > ├─>[PATCH v2 16/20] bus: cdmm: Add MIPS R5 arch support > > > > ├─>[PATCH v2 15/20] mips: cdmm: Add mti,mips-cdmm dtb node support > > > > > > both are not my call, but look ok to me. > > > > Can I add your Reviewed-by tag there then? > > only for 16/20. 15/20 looks ok to me, but I have not enough insides > on the hardware to say this is good. > > > > > ├─>[PATCH v2 13/20] mips: early_printk_8250: Use offset-sized IO-mem accessors > > > > > > that's broken. A reg shift of 2 doesn't mean we could use 32bit access > > > to the registers on other platforms. As I don't think adding some ifdefery > > > makes things nicer, just implement the your prom_putchar in board code. > > > > I thought about that initially, but then I decided to alter the generic > > early_printk_8250 code instead. My version of prom_putchar() would be almost > > the same as one implemented in the early_printk_8250 module except minor > > modification of replacing readb/writeb methods with readl/writel. So I didn't > > want to duplicate the code, but wanted to provide a general way to fix the > > problem potentially also for another platforms. > > > > Since you don't like this fix alternatively I'd suggest to add the reg_width > > parameter passed to the setup_8250_early_printk_port() method like this: > > -setup_8250_early_printk_port(unsigned long base, unsigned int reg_shift, > > - unsigned int timeout) > > +setup_8250_early_printk_port(unsigned long base, unsigned int reg_shift, > > + unsigned int reg_width, unsigned int timeout) > > > > By reg_width parameter we could determine the actual width of the register: > > static inline u8 serial_in(int offset) > > { > > - return readb(serial8250_base + (offset << serial8250_reg_shift)); > > + u8 ret = 0xFF; > > + > > + offset <<= serial8250_reg_shift; > > + switch (serial8250_reg_width) { > > + case 1: > > + ret = readb(serial8250_base + offset); > > + break; > > + case 2: > > + ret = readw(serial8250_base + offset); > > + break; > > + case 4: > > + ret = readl(serial8250_base + offset); > > + break; > > + default: > > + break; > > + } > > + > > + return ret; > > } > > > > The similar modification will be implemented for serial_out(). I'll also modify > > look at the lines of code you are adding. Doing your own prom_putchar will > probably have less lines. > > > What do you think about this? > > please do your own prom_putchar. One more time regarding this problem but in appliance to another part of the MIPS code. I've missed the patch to draw your attention to: [PATCH v2 14/20] mips: Use offset-sized IO-mem accessors in CPS debug printout There I've applied the same fix as in the patch: [PATCH v2 13/20] mips: early_printk_8250: Use offset-sized IO-mem accessors Since you don't like the way I initially fixed it, suppose there we don't have another way but to introduce something like CONFIG_MIPS_CPS_NS16550_WIDTH parameter to select a proper accessors, like sw in our case, and sb by defaul). Right? (Note UART_L is incorrectly created in that patch, I'll remove that macro in v3.) -Sergey > > > > > > > > > ├─>[PATCH v2 12/20] mips: MAAR: Add XPA mode support > > > > > > looks ok so far. > > > > Can I add your Reviewed-by tag there then? > > As I'm the maintainer of the part, I've simply applied it. > > > > > > > > ├─>[PATCH v2 10/20] mips: Add CONFIG/CONFIG6/Cause reg fields macro > > > > > > that is fine > > > > Can I add your Reviewed-by tag there then? > > As this didn't apply cleanly, I'll apply it after you've resent it. > IMHO no need for a Reviewed-by. > > > > > └─>[PATCH v2 09/20] mips: Add CP0 Write Merge config support > > > > > > this is IMHO a dangerous change. Enabling write merging for any > > > CPU supporting it might triggers bugs. Do it in your board bringup > > > code and at the moment I don't see a reason for the rest of that > > > patch. > > > > Let's at least leave the mm_config() implementation but without the write-merge > > enabling by default. Providing features availability macro > > cpu_has_mm_sysad/cpu_has_mm_full and c0 config fields > > do you have a user of that ? I'm not introducing code nobody uses. > > > I could use them to implement a code pattern like: > > > > + if (cpu_has_mm_full) { > > + unsigned int config0 = read_c0_config(); > > + config0 = (config0 & ~MIPS_CONF_MM) | MIPS_CONF_MM_FULL; > > + write_c0_config(config0); > > + } > > you know you are running on a R5 core, so you know you have MM_FULL. > No need to check this. > > > By doing so I can manually enable/disable the MM feature in the > > cpu-feature-overrides.h. Without that I'd have to locally define these macro, > > which isn't good seeing they are in fact generic and can be useful for other > > platforms with SYSAD and FULL MM feature available. What do you think? > > To me this is a hardware feature I expect to be done by firmware and > Linux shouldn't care about it, if it doesn't have any software > implications. > > Thomas. > > -- > Crap can work. Given enough thrust pigs will fly, but it's not necessarily a > good idea. [ RFC1925, 2.3 ]