dmaengine: fsl-edma: extract common fsl-edma code (no changes in behavior intended)

Quoted 94 lines · Krzysztof Kozlowski

Quoted 93 lines · Stefan Agner

Quoted 76 lines · Angelo Dureghello

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 <[email protected]>

---
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

drivers/dma/Makefile +1 -1

index 203a99d68315..66022f59fca4 100644
@@ -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

drivers/dma/fsl-edma-common.c new file +15 -0

new file mode 100644
index 000000000000..0ae7094f477a
@@ -0,0 +1,576 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (c) 2013-2014 Freescale Semiconductor, Inc
+// Copyright (c) 2017 Sysam, Angelo Dureghello  <[email protected]>
+
+#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

drivers/dma/fsl-edma-common.c line 25

Quoted 10 lines

drivers/dma/fsl-edma-common.c new file +10 -0

+ * 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

Quoted 6 lines

Quoted 3 lines

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

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.

--
Stefan

Quoted 13 lines

Best regards,
Krzysztof

Quoted 9 lines

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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