From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Viresh Kumar <viresh.kumar@st.com>
Cc: linus.walleij@linaro.org, pratyush.anand@st.com,
rajeev-dlh.kumar@st.com, bhupesh.sharma@st.com,
shiraz.hashim@st.com, vinod.koul@intel.com,
linux-kernel@vger.kernel.org, vipin.kumar@st.com,
armando.visconti@st.com, amit.virdi@st.com,
vipulkumar.samar@st.com, viresh.linux@gmail.com,
deepak.sikri@st.com, dan.j.williams@intel.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 10/18] dmaengine/amba-pl08x: Get rid of pl08x_pre_boundary()
Date: Fri, 29 Jul 2011 12:05:25 +0100 [thread overview]
Message-ID: <20110729110525.GG25640@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <c147ba3a755935e93fdb40b5531a6e18d34e0fd7.1311936524.git.viresh.kumar@st.com>
On Fri, Jul 29, 2011 at 04:19:20PM +0530, Viresh Kumar wrote:
> Pl080 Manual says: "Bursts do not cross the 1KB address boundary"
>
> We can program the controller to cross 1 KB boundary on a burst and controller
> can take care of this boundary condition by itself.
>
> Following is the discussion with ARM Technical Support Guys (David):
> [Viresh] Manual says: "Bursts do not cross the 1KB address boundary"
>
> What does that actually mean? As, Maximum size transferable with a single LLI is
> 4095 * 4 =16380 ~ 16KB. So, if we don't have src/dest address aligned to burst
> size, we can't use this big of an LLI.
>
> [David] There is a difference between bursts describing the total data
> transferred by the DMA controller and AHB bursts. Bursts described by the
> programmable parameters in the PL080 have no direct connection with the bursts
> that are seen on the AHB bus.
>
> The statement that "Bursts do not cross the 1KB address boundary" in the TRM is
> referring to AHB bursts, where this limitation is a requirement of the AHB spec.
> You can still issue bursts within the PL080 that are in excess o f 1KB. The
> PL080 will make sure that its bursts are broken down into legal AHB bursts which
> will be formatted to ensure that no AHB burst crosses a 1KB boundary.
>
> Based on above discussion, this patch removes all code related to 1 KB boundary
> as we are not required to handle this in driver.
Good. I'm glad someone's finally getting to the bottom of what's
actually required and what isn't... This driver has been a mess for
quite a long time and is in desperate need of these kinds of cleanups.
WARNING: multiple messages have this Message-ID (diff)
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 10/18] dmaengine/amba-pl08x: Get rid of pl08x_pre_boundary()
Date: Fri, 29 Jul 2011 12:05:25 +0100 [thread overview]
Message-ID: <20110729110525.GG25640@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <c147ba3a755935e93fdb40b5531a6e18d34e0fd7.1311936524.git.viresh.kumar@st.com>
On Fri, Jul 29, 2011 at 04:19:20PM +0530, Viresh Kumar wrote:
> Pl080 Manual says: "Bursts do not cross the 1KB address boundary"
>
> We can program the controller to cross 1 KB boundary on a burst and controller
> can take care of this boundary condition by itself.
>
> Following is the discussion with ARM Technical Support Guys (David):
> [Viresh] Manual says: "Bursts do not cross the 1KB address boundary"
>
> What does that actually mean? As, Maximum size transferable with a single LLI is
> 4095 * 4 =16380 ~ 16KB. So, if we don't have src/dest address aligned to burst
> size, we can't use this big of an LLI.
>
> [David] There is a difference between bursts describing the total data
> transferred by the DMA controller and AHB bursts. Bursts described by the
> programmable parameters in the PL080 have no direct connection with the bursts
> that are seen on the AHB bus.
>
> The statement that "Bursts do not cross the 1KB address boundary" in the TRM is
> referring to AHB bursts, where this limitation is a requirement of the AHB spec.
> You can still issue bursts within the PL080 that are in excess o f 1KB. The
> PL080 will make sure that its bursts are broken down into legal AHB bursts which
> will be formatted to ensure that no AHB burst crosses a 1KB boundary.
>
> Based on above discussion, this patch removes all code related to 1 KB boundary
> as we are not required to handle this in driver.
Good. I'm glad someone's finally getting to the bottom of what's
actually required and what isn't... This driver has been a mess for
quite a long time and is in desperate need of these kinds of cleanups.
next prev parent reply other threads:[~2011-07-29 11:05 UTC|newest]
Thread overview: 204+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-29 10:49 [PATCH 00/18] dmaengine/amba-pl08x updates Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-29 10:49 ` [PATCH 01/18] ARM: asm/pl080.h: Protect against multiple inclusion of header file Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-30 22:16 ` Linus Walleij
2011-07-30 22:16 ` Linus Walleij
2011-07-29 10:49 ` [PATCH 02/18] dmaengine/amba-pl08x: Resolve formatting issues Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-29 11:00 ` Russell King - ARM Linux
2011-07-29 11:00 ` Russell King - ARM Linux
2011-07-29 11:21 ` viresh kumar
2011-07-29 11:21 ` viresh kumar
2011-07-29 12:05 ` Koul, Vinod
2011-07-29 12:05 ` Koul, Vinod
2011-07-29 15:25 ` viresh kumar
2011-07-29 15:25 ` viresh kumar
2011-07-29 10:49 ` [PATCH 03/18] dmaengine/amba-pl08x: Complete doc comment for struct pl08x_txd Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-29 10:49 ` [PATCH 04/18] dmaengine/amba-pl08x: Remove redundant comment and rewrite original Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-29 12:09 ` Koul, Vinod
2011-07-29 12:09 ` Koul, Vinod
2011-07-29 15:47 ` viresh kumar
2011-07-29 15:47 ` viresh kumar
2011-07-29 16:34 ` Russell King - ARM Linux
2011-07-29 16:34 ` Russell King - ARM Linux
2011-07-30 22:32 ` Linus Walleij
2011-07-30 22:32 ` Linus Walleij
2011-07-30 22:57 ` Russell King - ARM Linux
2011-07-30 22:57 ` Russell King - ARM Linux
2011-07-30 23:37 ` Linus Walleij
2011-07-30 23:37 ` Linus Walleij
2011-07-31 5:51 ` viresh kumar
2011-07-31 5:51 ` viresh kumar
2011-07-31 9:06 ` Russell King - ARM Linux
2011-07-31 9:06 ` Russell King - ARM Linux
2011-07-29 10:49 ` [PATCH 05/18] dmaengine/amba-pl08x: Changing few prints to dev_dbg from dev_info Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-30 22:34 ` Linus Walleij
2011-07-30 22:34 ` Linus Walleij
2011-07-29 10:49 ` [PATCH 06/18] dmaengine/amba-pl08x: Simplify pl08x_ensure_on() Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-30 22:36 ` Linus Walleij
2011-07-30 22:36 ` Linus Walleij
2011-07-29 10:49 ` [PATCH 07/18] dmaengine/amba-pl08x: Enable/Disable amba_pclk with channel requests Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-30 12:07 ` Russell King - ARM Linux
2011-07-30 12:07 ` Russell King - ARM Linux
2011-07-30 13:05 ` Russell King - ARM Linux
2011-07-30 13:05 ` Russell King - ARM Linux
2011-07-30 23:53 ` Linus Walleij
2011-07-30 23:53 ` Linus Walleij
2011-07-31 0:04 ` Linus Walleij
2011-07-31 0:04 ` Linus Walleij
2011-07-31 17:04 ` Russell King - ARM Linux
2011-07-31 17:04 ` Russell King - ARM Linux
2011-08-02 9:05 ` Linus Walleij
2011-08-02 9:05 ` Linus Walleij
2011-08-03 12:55 ` Russell King - ARM Linux
2011-08-03 12:55 ` Russell King - ARM Linux
2011-08-09 19:50 ` Linus Walleij
2011-08-09 19:50 ` Linus Walleij
2011-07-29 10:49 ` [PATCH 08/18] dmaengine/amba-pl08x: No need to check "ch->signal < 0" Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-31 0:09 ` Linus Walleij
2011-07-31 0:09 ` Linus Walleij
2011-07-29 10:49 ` [PATCH 09/18] dmaengine/amba-pl08x: Schedule tasklet in case of error interrupt Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-29 12:16 ` Koul, Vinod
2011-07-29 12:16 ` Koul, Vinod
2011-07-29 13:02 ` Russell King - ARM Linux
2011-07-29 13:02 ` Russell King - ARM Linux
2011-07-29 15:30 ` viresh kumar
2011-07-29 15:30 ` viresh kumar
2011-08-04 4:25 ` Koul, Vinod
2011-08-04 4:25 ` Koul, Vinod
2011-08-04 5:54 ` viresh kumar
2011-08-04 5:54 ` viresh kumar
2011-08-04 5:32 ` Koul, Vinod
2011-08-04 5:32 ` Koul, Vinod
2011-08-14 8:29 ` Russell King - ARM Linux
2011-08-14 8:29 ` Russell King - ARM Linux
2011-07-31 0:19 ` Linus Walleij
2011-07-31 0:19 ` Linus Walleij
2011-07-31 5:33 ` viresh kumar
2011-07-31 5:33 ` viresh kumar
2011-07-29 10:49 ` [PATCH 10/18] dmaengine/amba-pl08x: Get rid of pl08x_pre_boundary() Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-29 11:05 ` Russell King - ARM Linux [this message]
2011-07-29 11:05 ` Russell King - ARM Linux
2011-07-29 12:32 ` Koul, Vinod
2011-07-29 12:32 ` Koul, Vinod
2011-07-29 15:58 ` viresh kumar
2011-07-29 15:58 ` viresh kumar
2011-07-29 12:19 ` Koul, Vinod
2011-07-29 12:19 ` Koul, Vinod
2011-07-29 15:40 ` viresh kumar
2011-07-29 15:40 ` viresh kumar
2011-07-31 0:24 ` Linus Walleij
2011-07-31 0:24 ` Linus Walleij
2011-07-29 10:49 ` [PATCH 11/18] dmaengine/amba-pl08x: max_bytes_per_lli is TRANSFER_SIZE * src_width (not MIN(width)) Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-31 0:27 ` Linus Walleij
2011-07-31 0:27 ` Linus Walleij
2011-07-31 9:09 ` Russell King - ARM Linux
2011-07-31 9:09 ` Russell King - ARM Linux
2011-07-29 10:49 ` [PATCH 12/18] dmaengine/amba-pl08x: Add prep_single_byte_llis() routine Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-29 11:06 ` Russell King - ARM Linux
2011-07-29 11:06 ` Russell King - ARM Linux
2011-07-29 11:30 ` viresh kumar
2011-07-29 11:30 ` viresh kumar
2011-07-29 10:49 ` [PATCH 13/18] dmaengine/amba-pl08x: Align lli_len to max(src.width, dst.width) Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-29 12:43 ` Koul, Vinod
2011-07-29 12:43 ` Koul, Vinod
2011-07-29 15:39 ` viresh kumar
2011-07-29 15:39 ` viresh kumar
2011-07-31 0:30 ` Linus Walleij
2011-07-31 0:30 ` Linus Walleij
2011-07-29 10:49 ` [PATCH 14/18] dmaengine/amba-pl08x: Choose peripheral bus as master bus Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-31 0:36 ` Linus Walleij
2011-07-31 0:36 ` Linus Walleij
2011-07-29 10:49 ` [PATCH 15/18] dmaengine/amba-pl08x: Pass flow controller information with slave channel data Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-29 11:10 ` Russell King - ARM Linux
2011-07-29 11:10 ` Russell King - ARM Linux
2011-07-29 11:31 ` viresh kumar
2011-07-29 11:31 ` viresh kumar
2011-07-31 0:40 ` Linus Walleij
2011-07-31 0:40 ` Linus Walleij
2011-07-31 5:36 ` viresh kumar
2011-07-31 5:36 ` viresh kumar
2011-07-29 10:49 ` [PATCH 16/18] dmaengine/amba-pl08x: Add support for sg len greater than one for slave transfers Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-31 0:41 ` Linus Walleij
2011-07-31 0:41 ` Linus Walleij
2011-08-14 8:36 ` Russell King - ARM Linux
2011-08-14 8:36 ` Russell King - ARM Linux
2011-08-15 10:11 ` Linus Walleij
2011-08-15 10:11 ` Linus Walleij
2011-08-18 8:38 ` Viresh Kumar
2011-08-18 8:38 ` Viresh Kumar
2011-08-21 8:33 ` Russell King - ARM Linux
2011-08-21 8:33 ` Russell King - ARM Linux
2011-08-23 4:22 ` Viresh Kumar
2011-08-23 4:22 ` Viresh Kumar
2011-08-23 5:20 ` Koul, Vinod
2011-08-23 5:20 ` Koul, Vinod
2011-08-26 3:41 ` Viresh Kumar
2011-08-26 3:41 ` Viresh Kumar
2011-08-26 8:03 ` Linus Walleij
2011-08-26 8:03 ` Linus Walleij
2011-08-26 8:51 ` Viresh Kumar
2011-08-26 8:51 ` Viresh Kumar
2011-09-01 10:07 ` Viresh Kumar
2011-09-01 10:07 ` Viresh Kumar
2011-09-07 18:42 ` Koul, Vinod
2011-09-07 18:42 ` Koul, Vinod
2011-09-07 23:01 ` Linus Walleij
2011-09-07 23:01 ` Linus Walleij
2011-09-08 3:50 ` Viresh Kumar
2011-09-08 3:50 ` Viresh Kumar
2011-09-08 10:29 ` Linus Walleij
2011-09-08 10:29 ` Linus Walleij
2011-09-08 21:54 ` [PATCH 16/18] dmaengine/ambhe rest oa-pl08x: " Vinod Koul
2011-09-08 21:54 ` Vinod Koul
2011-09-20 6:19 ` Vinod Koul
2011-09-20 6:19 ` Vinod Koul
2011-09-20 6:27 ` Viresh Kumar
2011-09-20 6:27 ` Viresh Kumar
2011-09-20 8:08 ` Vinod Koul
2011-09-20 8:08 ` Vinod Koul
2011-07-29 10:49 ` [PATCH 17/18] dmaengine/amba-pl08x: Check txd->llis_va before freeing dma_pool Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-31 0:44 ` Linus Walleij
2011-07-31 0:44 ` Linus Walleij
2011-07-29 10:49 ` [PATCH 18/18] dmaengine/amba-pl08x: Call pl08x_free_txd() instead of calling kfree() directly Viresh Kumar
2011-07-29 10:49 ` Viresh Kumar
2011-07-29 11:15 ` Russell King - ARM Linux
2011-07-29 11:15 ` Russell King - ARM Linux
2011-07-29 11:38 ` viresh kumar
2011-07-29 11:38 ` viresh kumar
2011-07-31 0:45 ` Linus Walleij
2011-07-31 0:45 ` Linus Walleij
2011-07-31 5:39 ` viresh kumar
2011-07-31 5:39 ` viresh kumar
2011-07-29 10:57 ` [PATCH 00/18] dmaengine/amba-pl08x updates Russell King - ARM Linux
2011-07-29 10:57 ` Russell King - ARM Linux
2011-07-29 11:14 ` viresh kumar
2011-07-29 11:14 ` viresh kumar
2011-07-29 11:19 ` Russell King - ARM Linux
2011-07-29 11:19 ` Russell King - ARM Linux
2011-07-29 11:23 ` viresh kumar
2011-07-29 11:23 ` viresh kumar
2011-07-29 12:43 ` Russell King - ARM Linux
2011-07-29 12:43 ` Russell King - ARM Linux
2011-07-29 15:22 ` viresh kumar
2011-07-29 15:22 ` viresh kumar
2011-07-29 11:58 ` Koul, Vinod
2011-07-29 11:58 ` Koul, Vinod
2011-08-01 5:30 ` viresh kumar
2011-08-01 5:30 ` viresh kumar
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