From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05499C4CEC9 for ; Wed, 18 Sep 2019 12:24:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D254E205F4 for ; Wed, 18 Sep 2019 12:24:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730719AbfIRMYH (ORCPT ); Wed, 18 Sep 2019 08:24:07 -0400 Received: from mga05.intel.com ([192.55.52.43]:54551 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726941AbfIRMYG (ORCPT ); Wed, 18 Sep 2019 08:24:06 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Sep 2019 05:24:06 -0700 X-IronPort-AV: E=Sophos;i="5.64,520,1559545200"; d="scan'208";a="387898031" Received: from jnikula-mobl3.fi.intel.com (HELO localhost) ([10.237.66.161]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Sep 2019 05:24:04 -0700 From: Jani Nikula To: Gerd Hoffmann , dri-devel@lists.freedesktop.org Cc: Maxime Ripard , open list , David Airlie , Gerd Hoffmann , Sean Paul Subject: Re: [PATCH v3 1/7] drm: add drm_print_bits In-Reply-To: <20190904054740.20817-2-kraxel@redhat.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20190904054740.20817-1-kraxel@redhat.com> <20190904054740.20817-2-kraxel@redhat.com> Date: Wed, 18 Sep 2019 15:24:01 +0300 Message-ID: <87sgotx066.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 04 Sep 2019, Gerd Hoffmann wrote: > New helper to print named bits of some value (think flags fields). > > Signed-off-by: Gerd Hoffmann > --- > include/drm/drm_print.h | 3 +++ > drivers/gpu/drm/drm_print.c | 33 +++++++++++++++++++++++++++++++++ > 2 files changed, 36 insertions(+) > > diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h > index 112165d3195d..12d4916254b4 100644 > --- a/include/drm/drm_print.h > +++ b/include/drm/drm_print.h > @@ -89,6 +89,9 @@ __printf(2, 3) > void drm_printf(struct drm_printer *p, const char *f, ...); > void drm_puts(struct drm_printer *p, const char *str); > void drm_print_regset32(struct drm_printer *p, struct debugfs_regset32 *regset); > +void drm_print_bits(struct drm_printer *p, > + unsigned long value, const char *bits[], > + unsigned int from, unsigned int to); > > __printf(2, 0) > /** > diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c > index ad302d71eeee..dfa27367ebb8 100644 > --- a/drivers/gpu/drm/drm_print.c > +++ b/drivers/gpu/drm/drm_print.c > @@ -185,6 +185,39 @@ void drm_printf(struct drm_printer *p, const char *f, ...) > } > EXPORT_SYMBOL(drm_printf); > > +/** > + * drm_print_bits - print bits to a &drm_printer stream > + * > + * Print bits (in flag fields for example) in human readable form. > + * The first name in the @bits array is for the bit indexed by @from. > + * > + * @p: the &drm_printer > + * @value: field value. > + * @bits: Array with bit names. > + * @from: start of bit range to print (inclusive). > + * @to: end of bit range to print (exclusive). > + */ > +void drm_print_bits(struct drm_printer *p, > + unsigned long value, const char *bits[], > + unsigned int from, unsigned int to) > +{ > + bool first = true; > + unsigned int i; > + > + for (i = from; i < to; i++) { > + if (!(value & (1 << i))) > + continue; for_each_set_bit from bitops.h? > + if (WARN_ON_ONCE(!bits[i-from])) > + continue; > + drm_printf(p, "%s%s", first ? "" : ",", > + bits[i-from]); I wonder about the usefulness of from and to, as well as indexing (i-from) for the strings. To limit the values to be printed in a more general way than range, you can use: drm_print_bits(p, value & GENMASK(h, l), bits); And obviously to adjust the starting position: drm_print_bits(p, value >> l, bits); Seems like a simple len parameter to indicate the ARRAY_SIZE() of bits would be more straighforward to guard against array overflow. drm_print_bits(p, value, bits, ARRAY_SIZE(bits)); BR, Jani. > + first = false; > + } > + if (first) > + drm_printf(p, "(none)"); > +} > +EXPORT_SYMBOL(drm_print_bits); > + > void drm_dev_printk(const struct device *dev, const char *level, > const char *format, ...) > { -- Jani Nikula, Intel Open Source Graphics Center