From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.13]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2B9EF3C140F for ; Mon, 4 May 2026 11:34:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777894474; cv=none; b=DNZlG2B4j8i9rjfFbp0Dy5jFPxdKgdje07k3YDzIxxGmayJ91u2dQo1QH2TFKVq5GlweV/guzopBrxeXpnIqp1Oi7MS0HhEJg/04S16SPXP6niL2VHRBVB7gQbAkwyWtyBhZTGzbPf2NyLw1x3QbpyV+ifbk1E4NrirS82H8s14= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777894474; c=relaxed/simple; bh=prMcaVJdpa2v2ahCOleV4GJ+fFGnc0wB+iTPX8a7A8I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ucb2Ew7MAOASvQKuGckjXgXK+9xW0hAc2I5wcnm5SO75EpLzmhx/AiJFaNdLrnV+p8nMGF6VoWeysx72BAwne6xhy9/6wZFYq1ECZ8Sb62H/OskI87YC5N4gv4GBJ+MhilDClS/6gTYGzyVNLzQVS5YhEsJsJaZCSalFuwy2pDw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Evx0V2Ok; arc=none smtp.client-ip=192.198.163.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Evx0V2Ok" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1777894472; x=1809430472; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=prMcaVJdpa2v2ahCOleV4GJ+fFGnc0wB+iTPX8a7A8I=; b=Evx0V2OkUC1Y6q3SuSotGyL6LUrNd6jp4faR0GvymTc9RGwK6dn6TuJj TgO2dlo7Ldc9a81SZoxD2gaBgqaoajOPADI6lbJgiF1R4EWDH3IYpqW5w PZKSL7SCFMw9catcpWffGH3LrrbuPezuOaI6kyo8ppUbzQfwzKwh5qzSg 8SWhIdqFFUG8HjLZbQPdlRxm+P/wm0mYlf3YaBnnE3avpdvO1TmnAshQL KIq/EhZ073vTW8BrRt3WEp4WTLxf55bHoLytyoF67EqNCCwtWkhDX2TDh sUD7WHbHpeJ4fpPWvag3fSYgneDi4EEzzUgE2g9CkKIZpJKhKgeZbb+Aw g==; X-CSE-ConnectionGUID: 87FtAAraQme1amv9lGHL7g== X-CSE-MsgGUID: haXth0pHSNiJ0lEcNxCSIw== X-IronPort-AV: E=McAfee;i="6800,10657,11775"; a="81315300" X-IronPort-AV: E=Sophos;i="6.23,215,1770624000"; d="scan'208";a="81315300" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 May 2026 04:34:32 -0700 X-CSE-ConnectionGUID: AI7RNkFtSre2SpVr7YgpYQ== X-CSE-MsgGUID: IPelCT5UTDKpHaBJKegKpw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,215,1770624000"; d="scan'208";a="240478345" Received: from hrotuna-mobl2.ger.corp.intel.com (HELO ahunter6-desk) ([10.245.245.92]) by fmviesa005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 May 2026 04:34:30 -0700 From: Adrian Hunter To: alexandre.belloni@bootlin.com Cc: Frank.Li@nxp.com, linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH V3 16/16] i3c: mipi-i3c-hci: Increase DMA transfer ring size to maximum Date: Mon, 4 May 2026 14:33:52 +0300 Message-ID: <20260504113352.38490-17-adrian.hunter@intel.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260504113352.38490-1-adrian.hunter@intel.com> References: <20260504113352.38490-1-adrian.hunter@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Organization: Intel Finland Oy, Registered Address: c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Content-Transfer-Encoding: 8bit The DMA transfer ring is currently limited to 16 entries, despite the MIPI I3C HCI supporting up to 32 devices. When the ring lacks space for a new transfer list, the driver returns -EBUSY, which can be unexpected for clients. Increase the DMA transfer ring size to the maximum supported value of 255 entries. This effectively eliminates ring-space exhaustion in practice and avoids the complexity of adding secondary queuing mechanisms. Even at the maximum size, the memory overhead remains small (approximately 24 bytes per entry by default). Signed-off-by: Adrian Hunter --- Changes in V2 and V3: None drivers/i3c/master/mipi-i3c-hci/dma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c index 4029d4d9e784..9549d98add4b 100644 --- a/drivers/i3c/master/mipi-i3c-hci/dma.c +++ b/drivers/i3c/master/mipi-i3c-hci/dma.c @@ -27,7 +27,7 @@ */ #define XFER_RINGS 1 /* max: 8 */ -#define XFER_RING_ENTRIES 16 /* max: 255 */ +#define XFER_RING_ENTRIES 255 /* max: 255 */ #define IBI_RINGS 1 /* max: 8 */ #define IBI_STATUS_RING_ENTRIES 32 /* max: 255 */ -- 2.51.0