Hi Stefan,

i am about to post a v9 in short.

On Tue, Aug 07, 2018 at 07:47:19PM +0200, Stefan Agner wrote:

On 07.08.2018 14:14, Krzysztof Kozlowski wrote:

quoted

On 7 August 2018 at 10:08, Stefan Agner [off-list ref] wrote:

quoted

On 03.08.2018 21:32, Angelo Dureghello wrote:

quoted

This patch adds a new fsl-edma-common module to allow new
mcf-edma module code to use most of the fsl-edma code.

Signed-off-by: Angelo Dureghello <redacted>
---
Changes for v2:
- patch splitted into 4
- add mcf-edma as minimal different parts from fsl-edma

Changes for v3:
none

Changes for v4:
- patch simplified from 4/4 into 2/2
- collecting all the mcf-edma-related changes

Changes for v5:
none

Changes for v6:
- adjusted comment header
- fixed bit shift with BIT()
- we need to free the interrupts at remove(), so removed all devm_
  interrupt related calls

Changes for v7:
none

Changes for v8:
- patch rewritten from scratch, splitted into 3, common code isolated,
  minimal changes from the original Freescale code have been done.
  The patch has been tested with both Iris + Colibri Vybrid VF50 and
  stmark2/mcf54415 Coldfire boards.
---
 drivers/dma/Makefile          |   2 +-
 drivers/dma/fsl-edma-common.c | 576 ++++++++++++++++++++++++++++
 drivers/dma/fsl-edma-common.h | 196 ++++++++++
 drivers/dma/fsl-edma.c        | 697 +---------------------------------
 4 files changed, 774 insertions(+), 697 deletions(-)
 create mode 100644 drivers/dma/fsl-edma-common.c
 create mode 100644 drivers/dma/fsl-edma-common.h

diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 203a99d68315..66022f59fca4 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile

@@ -31,7 +31,7 @@ obj-$(CONFIG_DW_AXI_DMAC) += dw-axi-dmac/
 obj-$(CONFIG_DW_DMAC_CORE) += dw/
 obj-$(CONFIG_EP93XX_DMA) += ep93xx_dma.o
 obj-$(CONFIG_FSL_DMA) += fsldma.o
-obj-$(CONFIG_FSL_EDMA) += fsl-edma.o
+obj-$(CONFIG_FSL_EDMA) += fsl-edma.o fsl-edma-common.o
 obj-$(CONFIG_FSL_RAID) += fsl_raid.o
 obj-$(CONFIG_HSU_DMA) += hsu/
 obj-$(CONFIG_IMG_MDC_DMA) += img-mdc-dma.o

diff --git a/drivers/dma/fsl-edma-common.c b/drivers/dma/fsl-edma-common.c
new file mode 100644
index 000000000000..0ae7094f477a
--- /dev/null
+++ b/drivers/dma/fsl-edma-common.c

@@ -0,0 +1,576 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (c) 2013-2014 Freescale Semiconductor, Inc
+// Copyright (c) 2017 Sysam, Angelo Dureghello  <angelo@sysam.it>
+
+#include <linux/dmapool.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "fsl-edma-common.h"
+
+/*
+ * R/W functions for big- or little-endian registers:
+ * The eDMA controller's endian is independent of the CPU core's endian.
+ * For the big-endian IP module, the offset for 8-bit or 16-bit registers
+ * should also be swapped opposite to that in little-endian IP.
+ */
+u32 edma_readl(struct fsl_edma_engine *edma, void __iomem *addr)
+{
+     if (edma->big_endian)
+             return ioread32be(addr);
+     else
+             return ioread32(addr);
+}
+EXPORT_SYMBOL_GPL(edma_readl);

In 3/3 you link the common object into the two modules individually:

obj-$(CONFIG_FSL_EDMA) += fsl-edma.o fsl-edma-common.o
obj-$(CONFIG_MCF_EDMA) += mcf-edma.o fsl-edma-common.o

Therefor you do not access those functions from another module (they are
within the module). No exporting should be necessary. Drop all those
exports.

The fsl-edma-common will be its own module so the exports are
necessary for proper linking/modpost.

Hm, oh I see, I got that wrong.

We could use
fsl-edma-all-y = fsl-edma.o fsl-edma-common.o
obj-$(CONFIG_FSL_EDMA) += fsl-edma-all.o
mcf-edma-all-y = mcf-edma.o fsl-edma-common.o
obj-$(CONFIG_MCF_EDMA) += mcf-edma-all.o

to create two modules but that duplicates some code. It probably
wouldn't matter in practise since the two IPs are used on different
architecture...

However, if we stay with the three modules approach, we should introduce
a hidden config symbol, e.g.

config FSL_EDMA_COMMON
	tristate

In FSL_EDMA/MCF_EDMA use
	select FSL_EDMA_COMMON

And in the Makefile
obj-$(CONFIG_FSL_EDMA_COMMON) += fsl-edma-common.o
obj-$(CONFIG_FSL_EDMA) += fsl-edma.o
obj-$(CONFIG_MCF_EDMA) += mcf-edma.o

There was already a discussion with Vinod and Geert on this, and i 
finally previously changed things in this way 

obj-$(CONFIG_FSL_EDMA) += fsl-edma.o fsl-edma-common.o

The idea was to simplify things avoiding to use an additional
config symbol, as i did initially. It's a common pattern in 
several Makefiles (e.g.drivers/net/ethernet/8390/Makefile and 
drivers/scsi/Makefile).
Also we have a single common code part since obj-y is a list, 
and IIRC it's filtered for duplicates.
So if can be ok for you too, i would not roll back again.

However, I do not like that the compiler can no longer inline simple
acesors like edma_(readl|writel). So if we stay with the three modules
approach then move at least the accesors and
to_fsl_edma_chan/to_fsl_edma_desc as inline functions to the header
file.

I agree too, my initial patch was a single separate driver. But it
resulted in too much duplicated code, so a common module has been
required. Btw, seems i cannot inline those functions. fsl-edma-common.h 
is included from both fsl-edma-common.c and mcf/fsl-edma.c resulting
in multiple definitions linking error.

Mainly until v7 there was several discussions and a first approval, 
if possible i would not change again heavily the patch structure for
a bug that seemss already been fixed.

So i fixed all the possible points of this thread and organized next 
patch as 

1/4 dmaengine: fsl-edma: extract common fsl-edma code (no changes ..
2/4 dmaengine: fsl-edma: add edma version and configurable registers
3/4 dmaengine: fsl-edma: fix macros
4/4 dmaengine: fsl-edma: add ColdFire mcf5441x edma support

Let me know if you have any other point or if can proceed.

Best regards,
Angelo Dureghello

--
Stefan

quoted

Best regards,
Krzysztof

quoted

If possible I would prefer if you start with cleanup/conversions, then
split-up and finally add functionality.

So ideally:
1. Use macros for preprocessor defines (where you move to BIT/GENMASK)
2. Split
3. Add EDMA macros etc.
4. Add ColdFire mcf5441x edma support

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