From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.11]) (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 BCA5743DA51 for ; Wed, 3 Jun 2026 09:08:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780477723; cv=none; b=svXxvEYRoaJ81Ur4v+Mqzl4kEDVtubrmXUJQUxAeA4HCz/dFvd6/Q9MIlprt9ZHcZf5E+B/kKVAfY+0qFxSjuhL8eCTe++YOS7zKPEK/IkU0hWvMdvUKXVkbHh3RspR914B2zXy0TfKEPGH69rHRjhklkAIoA75igk/U9CmTvuo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780477723; c=relaxed/simple; bh=U8i31m+uoQ82HkqAIhMysB7L27S+R96vCj6fh1UOFvk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qooMMvi8Nx3Og3AQDZFDfOKlyPpSdZANc4WrW9vQYXKJNzfvdPPypoQS70dSen2z/UZPxAASqCa6okxod7AYXZpR4yM00sf6knuTNBIZqG4OCqy0NjnGnCIa92cTKw5z885LR4rMO2C+gPZQSTEF/K9ZW3n4G9CIy4gFo0i3pPI= 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=CUZD+AjZ; arc=none smtp.client-ip=192.198.163.11 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="CUZD+AjZ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1780477721; x=1812013721; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=U8i31m+uoQ82HkqAIhMysB7L27S+R96vCj6fh1UOFvk=; b=CUZD+AjZYHs/55GSQEunzemDLMJJ5m+EFq7ffxoDYzC1VBljYpaTBr6f Wvb3XPc5ewLQo3WXCUb1cdws7acHzZK0nx3rVkHFV998k1BE72DEhSJnY /M/ANYf11vvTOps5vqsW1bOksfw1FPp6imhfIIi0IV7MbFqOPV4W/yKlE DeoikOeu7jHDP6YKO90C/NU0XzzMEFH5tqpGtGEMFWpI8E/cAIFuAL7Pp DoPkxVHlbh890O2XpPL+3TLUt1EQJHYN4qNj2TD7SHNMhPB3QL4booF/o SVD0vWqelDjUE+lG+Cnwbuevd8fZi7Li26Wk2Hqq/VQDOmGZr7uciopf8 A==; X-CSE-ConnectionGUID: Gw3S06VHQdmRVAcogF9ZvA== X-CSE-MsgGUID: oqVnIN00RFmaT2Q94KM7oQ== X-IronPort-AV: E=McAfee;i="6800,10657,11805"; a="91852678" X-IronPort-AV: E=Sophos;i="6.24,184,1774335600"; d="scan'208";a="91852678" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by fmvoesa105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jun 2026 02:08:41 -0700 X-CSE-ConnectionGUID: QP1Yb5wXSe6tjNXdu4+W8A== X-CSE-MsgGUID: XJN9rBjDRSmcKiSwcDsv9g== X-ExtLoop1: 1 Received: from ijarvine-mobl1.ger.corp.intel.com (HELO ahunter6-desk) ([10.245.244.137]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jun 2026 02:08:40 -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 V5 17/17] i3c: mipi-i3c-hci: Increase DMA transfer ring size to maximum Date: Wed, 3 Jun 2026 12:07:54 +0300 Message-ID: <20260603090754.16252-18-adrian.hunter@intel.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260603090754.16252-1-adrian.hunter@intel.com> References: <20260603090754.16252-1-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 V5: None 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