From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.19]) (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 D90FE4DD6CB for ; Fri, 15 May 2026 16:27:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778862428; cv=none; b=NXVqX8TApgwBe0jzLe2lFW8j26T4ATCecNTIW+Ri447rMma0aFbeMmTSlnwauqVm0oduPguP97AgpCqVcZOQSEEVo82aLQv+JU2cVwkHtiylbFf5Jybpqch8StQGN9Qj6jFhG15K388ok6Tgx0V2n3/nsOBlVersp7nQTjxb5L8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778862428; c=relaxed/simple; bh=nToMwuW9z9iC87oDlmlW2x/HtDiZ1V7hTueP90c3kwg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JrhhqxGLvnFIDuTY7Fpg52VmIDLrcQXuR13+xWsntZmYHcNEEeEagfStl5jSG9fpNNf8WcNy4n4YxGa1WtM6rLREDEY2NhgueDFTfWhyXr1r6GZP36aadH1aC8CcIuIK9YnTZZspuH675hW58Qg/G0VYBPQois3mR1cBTdcz7LI= 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=CqDRd99o; arc=none smtp.client-ip=198.175.65.19 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="CqDRd99o" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1778862427; x=1810398427; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=nToMwuW9z9iC87oDlmlW2x/HtDiZ1V7hTueP90c3kwg=; b=CqDRd99o0xO7RU8U1v81xH5MI2KQLB+xb+mPdT+/tRHeqZ6jHvj5uwsu 2zQJHZ59oCUeSU7YHtSOnVk2LRm4A02Tp0QwcpyOu0NL76zuNK8s95UQ6 PIfmX3n0MmEhI9wE0LkxsP+iNRUmY+ppU+VNvwH9uth3FQk5f8H/tGk7u vt28alOvh7PB8ShYqSsXIiFTmghZGvI9YsavMzVM4O0L/eiPiad703vkB 7bqkabSObDcYiyB6d+HKS8bMmNwmVEHSOq/5mnqSeYrpvsxAgmy/hHb/v aQzhuX5GKJvusB8O6u3/fgHGq+23mDyMqD4UlCIUws3BVKFRzTiNpMwwa Q==; X-CSE-ConnectionGUID: PGv7k1vTReC0/42ExJSp/w== X-CSE-MsgGUID: P3M2XDLBS7+ZeiEi042ocQ== X-IronPort-AV: E=McAfee;i="6800,10657,11787"; a="79785313" X-IronPort-AV: E=Sophos;i="6.23,236,1770624000"; d="scan'208";a="79785313" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by orvoesa111.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 May 2026 09:27:07 -0700 X-CSE-ConnectionGUID: lhf+66zoS8eDkq99WLvdLg== X-CSE-MsgGUID: DSHfI1QoQYC5tON6cqrTyQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,236,1770624000"; d="scan'208";a="238857310" Received: from ijarvine-mobl1.ger.corp.intel.com (HELO ahunter6-desk) ([10.245.245.28]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 May 2026 09:27:05 -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 V4 17/17] i3c: mipi-i3c-hci: Increase DMA transfer ring size to maximum Date: Fri, 15 May 2026 19:26:21 +0300 Message-ID: <20260515162621.57719-18-adrian.hunter@intel.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260515162621.57719-1-adrian.hunter@intel.com> References: <20260515162621.57719-1-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 Reviewed-by: Frank Li --- Changes in V4: Add Frank's Rev'd-by 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 0136f3064ada..5c6ae2055618 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