From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (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 553DA56B98 for ; Thu, 21 Mar 2024 19:04:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711047878; cv=none; b=jP59jIUl7H6VlnaA4SO5HgPyKatzU/VyzQv65j2HM2eJ6tfb0trH7qlXBJqPXDZj+387VFct9FOYCqFO1G+qRUu0Xd0Z+Ct5rPh/EHcgLfJN8vrBxoQkVudBSiFrrzZs/ojgFe2+jyxVwUaFKwqlThDjvinWB+iLeoq2ZcwBdag= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711047878; c=relaxed/simple; bh=tf7/M6A3LrlyRfNWUbKqGzJe02wtK8NL3nxnd41+0Ds=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Dj0RSbcplbZ40+KixpwXvW5dswHxoVrw595UzIA/7Wt1aN24TJU1vyKNjVB10N+mnEw6JP+HV0tuuel+ylBLG6u71Ksk7qjilj1n4fMClaHNvsSWDvBXONgf4erWBqWRnptOUfV3eQHUP4e6E3/ZQlIiINpovSRgSCDfJ1CDexg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=LAQjP2SX; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="LAQjP2SX" Received: from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi [81.175.209.231]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 01D5A2B3; Thu, 21 Mar 2024 20:04:05 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1711047846; bh=tf7/M6A3LrlyRfNWUbKqGzJe02wtK8NL3nxnd41+0Ds=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LAQjP2SXNe2OKp3B+lhWOYhTgHgrMuSAc7GSW2JNmggmKcN4cmhilIUbrQa43FvN0 UAuf0FTNquKKxw7x7fuvdrsq7ymNrrr5E7adnHFTPj1W9h8q0ocKAsKte9EWgYxGlw bmbKNF3TLXCWsTPOTZebHmmYGd0le2gmyJcBb5rU= Date: Thu, 21 Mar 2024 21:04:30 +0200 From: Laurent Pinchart To: Umang Jain Cc: linux-staging@lists.linux.dev, Stefan Wahren , Dan Carpenter , Kieran Bingham , Phil Elwell , Dave Stevenson , Greg KH Subject: Re: [PATCH v3 3/6] staging: vc04_services: vchiq_arm: Drop g_cache_line_size Message-ID: <20240321190430.GW9582@pendragon.ideasonboard.com> References: <20240321103740.808561-1-umang.jain@ideasonboard.com> <20240321103740.808561-4-umang.jain@ideasonboard.com> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240321103740.808561-4-umang.jain@ideasonboard.com> Hi Umang, Thank you for the patch. On Thu, Mar 21, 2024 at 04:07:37PM +0530, Umang Jain wrote: > The cache-line-size is cached in struct vchiq_platform_info. > There is no need to cache this again via g_cache_line_size. > Instead use the value from vchiq_platform_info directly. > > Signed-off-by: Umang Jain > --- > .../interface/vchiq_arm/vchiq_arm.c | 49 +++++++++++-------- > 1 file changed, 29 insertions(+), 20 deletions(-) > > diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c > index 73405a1f50ee..01b4e4b010c6 100644 > --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c > +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c > @@ -71,6 +71,17 @@ static struct vchiq_device *bcm2835_audio; > static struct vchiq_device *bcm2835_camera; > > static struct vchiq_platform_info bcm2835_info = { > + /* > + * This value is the size of the L2 cache lines as understood by the > + * VPU firmware, which determines the required alignment of the > + * offsets/sizes in pagelists. This belongs to a kerneldoc block for the vchiq_drvdata structure. > + * > + * Modern VPU firmware looks for a DT "cache-line-size" property in > + * the VCHIQ node and will overwrite it with the actual L2 cache size, > + * which the kernel must then respect. That property was rejected > + * upstream, so we have to use the VPU firmware's compatibility value > + * of 32. This should be moved to the same location too, but the comment is a bit outdated, as the driver uses 64 for bcm2836 and compatible. You could write * Modern VPU firmware looks for a DT "cache-line-size" property in the * VCHIQ node and will overwrite it with the actual L2 cache size, which * the kernel must then respect. That property was rejected upstream, so * we use a value derived from the compatible string. > + */ > .cache_line_size = 32, > }; > > @@ -130,17 +141,6 @@ struct vchiq_pagelist_info { > }; > > static void __iomem *g_regs; > -/* This value is the size of the L2 cache lines as understood by the > - * VPU firmware, which determines the required alignment of the > - * offsets/sizes in pagelists. > - * > - * Modern VPU firmware looks for a DT "cache-line-size" property in > - * the VCHIQ node and will overwrite it with the actual L2 cache size, > - * which the kernel must then respect. That property was rejected > - * upstream, so we have to use the VPU firmware's compatibility value > - * of 32. > - */ > -static unsigned int g_cache_line_size = 32; > static unsigned int g_fragments_size; > static char *g_fragments_base; > static char *g_free_fragments; > @@ -211,6 +211,8 @@ static struct vchiq_pagelist_info * > create_pagelist(struct vchiq_instance *instance, char *buf, char __user *ubuf, > size_t count, unsigned short type) > { > + struct platform_device *pdev; > + struct vchiq_drv_mgmt *drv_mgmt; > struct pagelist *pagelist; > struct vchiq_pagelist_info *pagelistinfo; > struct page **pages; > @@ -225,6 +227,9 @@ create_pagelist(struct vchiq_instance *instance, char *buf, char __user *ubuf, > if (count >= INT_MAX - PAGE_SIZE) > return NULL; > > + pdev = to_platform_device(instance->state->dev->parent); > + drv_mgmt = platform_get_drvdata(pdev); drv_mgmt = dev_get_drvdata(instance->state->dev->parent); Same below. On a related note, I think you should move the contents of vchiq_connected.c to vchiq_arm.c. It's a small file, containing two functions only, with one of them being called only from vchiq_arm.c. It would allow you to make the vchiq_drv_mgmt structure private to vchiq_arm.c. This can be done on top of this series. Reviewed-by: Laurent Pinchart > + > if (buf) > offset = (uintptr_t)buf & (PAGE_SIZE - 1); > else > @@ -367,9 +372,9 @@ create_pagelist(struct vchiq_instance *instance, char *buf, char __user *ubuf, > > /* Partial cache lines (fragments) require special measures */ > if ((type == PAGELIST_READ) && > - ((pagelist->offset & (g_cache_line_size - 1)) || > + ((pagelist->offset & (drv_mgmt->pinfo->cache_line_size - 1)) || > ((pagelist->offset + pagelist->length) & > - (g_cache_line_size - 1)))) { > + (drv_mgmt->pinfo->cache_line_size - 1)))) { > char *fragments; > > if (down_interruptible(&g_free_fragments_sema)) { > @@ -395,12 +400,17 @@ static void > free_pagelist(struct vchiq_instance *instance, struct vchiq_pagelist_info *pagelistinfo, > int actual) > { > + struct platform_device *pdev; > + struct vchiq_drv_mgmt *drv_mgmt; > struct pagelist *pagelist = pagelistinfo->pagelist; > struct page **pages = pagelistinfo->pages; > unsigned int num_pages = pagelistinfo->num_pages; > > dev_dbg(instance->state->dev, "arm: %pK, %d\n", pagelistinfo->pagelist, actual); > > + pdev = to_platform_device(instance->state->dev->parent); > + drv_mgmt = platform_get_drvdata(pdev); > + > /* > * NOTE: dma_unmap_sg must be called before the > * cpu can touch any of the data/pages. > @@ -416,10 +426,10 @@ free_pagelist(struct vchiq_instance *instance, struct vchiq_pagelist_info *pagel > g_fragments_size; > int head_bytes, tail_bytes; > > - head_bytes = (g_cache_line_size - pagelist->offset) & > - (g_cache_line_size - 1); > + head_bytes = (drv_mgmt->pinfo->cache_line_size - pagelist->offset) & > + (drv_mgmt->pinfo->cache_line_size - 1); > tail_bytes = (pagelist->offset + actual) & > - (g_cache_line_size - 1); > + (drv_mgmt->pinfo->cache_line_size - 1); > > if ((actual >= 0) && (head_bytes != 0)) { > if (head_bytes > actual) > @@ -434,8 +444,8 @@ free_pagelist(struct vchiq_instance *instance, struct vchiq_pagelist_info *pagel > (tail_bytes != 0)) > memcpy_to_page(pages[num_pages - 1], > (pagelist->offset + actual) & > - (PAGE_SIZE - 1) & ~(g_cache_line_size - 1), > - fragments + g_cache_line_size, > + (PAGE_SIZE - 1) & ~(drv_mgmt->pinfo->cache_line_size - 1), > + fragments + drv_mgmt->pinfo->cache_line_size, > tail_bytes); > > down(&g_free_fragments_mutex); > @@ -478,8 +488,7 @@ static int vchiq_platform_init(struct platform_device *pdev, struct vchiq_state > if (err < 0) > return err; > > - g_cache_line_size = drv_mgmt->pinfo->cache_line_size; > - g_fragments_size = 2 * g_cache_line_size; > + g_fragments_size = 2 * drv_mgmt->pinfo->cache_line_size; > > /* Allocate space for the channels in coherent memory */ > slot_mem_size = PAGE_ALIGN(TOTAL_SLOTS * VCHIQ_SLOT_SIZE); -- Regards, Laurent Pinchart