Determine the number of DMA channels by 'dma-channels' property

PATCH Superseded Zong Li 2 participants 7 messages Jan 14, 2022 – Jan 17, 2022

Subsystems (6)

Device tree bindings RISC-V dmaengine SiFive drivers +2 more subsystems

lore

Share & tools

lore

Zong Li

author

2022-01-14 09:17 UTC #0 lore raw

v3 cover Determine the number of DMA channels by 'dma-channels' property

The PDMA driver currently assumes there are four channels by default, it might cause the error if there is actually less than four channels. Change that by getting number of channel dynamically from device tree. For backwards-compatible, it uses the default value (i.e. 4) when there is no 'dma-channels' information in dts.

This patch set contains the dts and dt-bindings change.

Changed in v3:
- Fix allocating wrong size
- Return error if 'dma-channels' is larger than maximum

Changed in v2:
- Rebase on tag v5.16
- Use 4 as default value of dma-channels

Zong Li (3):
riscv: dts: Add dma-channels property in dma node
dt-bindings: Add dma-channels for pdma device node
dmaengine: sf-pdma: Get number of channel by device tree

 .../bindings/dma/sifive,fu540-c000-pdma.yaml  |  7 +++++++
 .../boot/dts/microchip/microchip-mpfs.dtsi    |  1 +
 arch/riscv/boot/dts/sifive/fu540-c000.dtsi    |  1 +
 drivers/dma/sf-pdma/Makefile                  |  2 ++
 drivers/dma/sf-pdma/sf-pdma.c                 | 20 ++++++++++++-------
 drivers/dma/sf-pdma/sf-pdma.h                 |  8 ++------
 6 files changed, 26 insertions(+), 13 deletions(-)

Signature · 1 line

2.31.1

Zong Li

author

2022-01-14 09:17 UTC #1 lore raw

PATCH v3 1/3 riscv: dts: Add dma-channels property in dma node

Add dma-channels property, then we can determine how many channels there by device tree.

Signed-off-by Zong Li <[email protected]>

---
 arch/riscv/boot/dts/microchip/microchip-mpfs.dtsi | 1 +
 arch/riscv/boot/dts/sifive/fu540-c000.dtsi        | 1 +
 2 files changed, 2 insertions(+)

arch/riscv/boot/dts/microchip/microchip-mpfs.dtsi +1 -0

index c9f6d205d2ba..3c48f2d7a4a4 100644
@@ -188,6 +188,7 @@ dma@3000000 {
 			reg = <0x0 0x3000000 0x0 0x8000>;
 			interrupt-parent = <&plic>;
 			interrupts = <23 24 25 26 27 28 29 30>;
+			dma-channels = <4>;
 			#dma-cells = <1>;
 		};

arch/riscv/boot/dts/sifive/fu540-c000.dtsi +1 -0

index 0655b5c4201d..2bdfe7f06e4b 100644
@@ -171,6 +171,7 @@ dma: dma@3000000 {
 			reg = <0x0 0x3000000 0x0 0x8000>;
 			interrupt-parent = <&plic0>;
 			interrupts = <23 24 25 26 27 28 29 30>;
+			dma-channels = <4>;
 			#dma-cells = <1>;
 		};
 		uart1: serial@10011000 {

Signature · 1 line

2.31.1

Zong Li

author

2022-01-14 09:17 UTC #2 lore raw

PATCH v3 2/3 dt-bindings: Add dma-channels for pdma device node

In reply to Zong Li

Add dma-channels property, then we can determine how many channels there by device tree, rather than statically defines it in PDMA driver

Signed-off-by Zong Li <[email protected]>

---
 .../devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml    | 7 +++++++
 1 file changed, 7 insertions(+)

Documentation/devicetree/bindings/dma/sifive,fu540-c000-pdma.yaml +7 -0

index d32a71b975fe..3dbb8caefc17 100644
@@ -34,6 +34,12 @@ properties:
     minItems: 1
     maxItems: 8
 
+  dma-channels:
+    description: For backwards-compatible, the default value is 4
+    minimum: 1
+    maximum: 4
+    default: 4
+
   '#dma-cells':
     const: 1

@@ -50,6 +56,7 @@ examples:
     dma@3000000 {
       compatible = "sifive,fu540-c000-pdma";
       reg = <0x3000000 0x8000>;
+      dma-channels = <4>;
       interrupts = <23 24 25 26 27 28 29 30>;
       #dma-cells = <1>;
     };

Signature · 1 line

2.31.1

Zong Li

author

2022-01-14 09:18 UTC #3 lore raw

PATCH v3 3/3 dmaengine: sf-pdma: Get number of channel by device tree

In reply to Zong Li

It currently assumes that there are always four channels, it would cause the error if there is actually less than four channels. Change that by getting number of channel from device tree.

For backwards-compatible, it uses the default value (i.e. 4) when there is no 'dma-channels' information in dts.

Signed-off-by Zong Li <[email protected]>

---
 drivers/dma/sf-pdma/Makefile  |  2 ++
 drivers/dma/sf-pdma/sf-pdma.c | 20 +++++++++++++-------
 drivers/dma/sf-pdma/sf-pdma.h |  8 ++------
 3 files changed, 17 insertions(+), 13 deletions(-)

drivers/dma/sf-pdma/Makefile +2 -0

index 764552ab8d0a..cf1daff7e445 100644
@@ -1 +1,3 @@
 obj-$(CONFIG_SF_PDMA)   += sf-pdma.o
+
+CFLAGS_sf-pdma.o += -O0

drivers/dma/sf-pdma/sf-pdma.c +13 -7

index f12606aeff87..1264add9897e 100644
@@ -482,9 +482,7 @@ static void sf_pdma_setup_chans(struct sf_pdma *pdma)
 static int sf_pdma_probe(struct platform_device *pdev)
 {
 	struct sf_pdma *pdma;
-	struct sf_pdma_chan *chan;
 	struct resource *res;
-	int len, chans;
 	int ret;
 	const enum dma_slave_buswidth widths =
 		DMA_SLAVE_BUSWIDTH_1_BYTE | DMA_SLAVE_BUSWIDTH_2_BYTES |

@@ -492,13 +490,21 @@ static int sf_pdma_probe(struct platform_device *pdev)
 		DMA_SLAVE_BUSWIDTH_16_BYTES | DMA_SLAVE_BUSWIDTH_32_BYTES |
 		DMA_SLAVE_BUSWIDTH_64_BYTES;
 
-	chans = PDMA_NR_CH;
-	len = sizeof(*pdma) + sizeof(*chan) * chans;
-	pdma = devm_kzalloc(&pdev->dev, len, GFP_KERNEL);
+	pdma = devm_kzalloc(&pdev->dev, sizeof(*pdma), GFP_KERNEL);
 	if (!pdma)
 		return -ENOMEM;
 
-	pdma->n_chans = chans;
+	ret = of_property_read_u32(pdev->dev.of_node, "dma-channels",
+				   &pdma->n_chans);
+	if (ret) {
+		dev_notice(&pdev->dev, "set number of channels to default value: 4\n");
+		pdma->n_chans = PDMA_MAX_NR_CH;
+	}
+
+	if (pdma->n_chans > PDMA_MAX_NR_CH) {
+		dev_err(&pdev->dev, "the number of channels exceeds the maximum\n");
+		return -EINVAL;
+	}
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	pdma->membase = devm_ioremap_resource(&pdev->dev, res);

@@ -556,7 +562,7 @@ static int sf_pdma_remove(struct platform_device *pdev)
 	struct sf_pdma_chan *ch;
 	int i;
 
-	for (i = 0; i < PDMA_NR_CH; i++) {
+	for (i = 0; i < pdma->n_chans; i++) {
 		ch = &pdma->chans[i];
 
 		devm_free_irq(&pdev->dev, ch->txirq, ch);

drivers/dma/sf-pdma/sf-pdma.h +2 -6

index 0c20167b097d..8127d792f639 100644
@@ -22,11 +22,7 @@
 #include "../dmaengine.h"
 #include "../virt-dma.h"
 
-#define PDMA_NR_CH					4
-
-#if (PDMA_NR_CH != 4)
-#error "Please define PDMA_NR_CH to 4"
-#endif
+#define PDMA_MAX_NR_CH					4
 
 #define PDMA_BASE_ADDR					0x3000000
 #define PDMA_CHAN_OFFSET				0x1000

@@ -118,7 +114,7 @@ struct sf_pdma {
 	void __iomem            *membase;
 	void __iomem            *mappedbase;
 	u32			n_chans;
-	struct sf_pdma_chan	chans[PDMA_NR_CH];
+	struct sf_pdma_chan	chans[PDMA_MAX_NR_CH];
 };
 
 #endif /* _SF_PDMA_H */

Signature · 1 line

2.31.1

kernel test robot

build bot

2022-01-14 17:32 UTC #4 lore raw

Re: [PATCH v3 3/3] dmaengine: sf-pdma: Get number of channel by device tree

Thank you for the patch! Perhaps something to improve:

Hi Zong,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on vkoul-dmaengine/next]
[also build test WARNING on v5.16]
[cannot apply to robh/for-next next-20220114]
[If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Zong-Li/Determine-the-number-of-DMA-channels-by-dma-channels-property/20220114-172017
base:   https://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine.git next
config: riscv-allmodconfig (https://download.01.org/0day-ci/archive/20220115/202201150140.AnHdUdow-lkp(a)intel.com/config)
compiler: riscv64-linux-gcc (GCC) 11.2.0

reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/efa33512fd463fd6e29750992df1d40513eb5a7c
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Zong-Li/Determine-the-number-of-DMA-channels-by-dma-channels-property/20220114-172017 git checkout efa33512fd463fd6e29750992df1d40513eb5a7c
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=riscv SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate

Reported-by kernel test robot <[email protected]>

All warnings (new ones prefixed by >>):

In file included from include/linux/compiler_types.h:85,
from <command-line>:
arch/riscv/include/asm/jump_label.h: In function 'vchan_cookie_complete':

>> include/linux/compiler-gcc.h:86:38: warning: 'asm' operand 0 probably does not match constraints
      86 | #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
         |                                      ^~~
   arch/riscv/include/asm/jump_label.h:20:9: note: in expansion of macro 'asm_volatile_goto'
      20 |         asm_volatile_goto(
         |         ^~~~~~~~~~~~~~~~~
   include/linux/compiler-gcc.h:86:38: error: impossible constraint in 'asm'
      86 | #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
         |                                      ^~~
   arch/riscv/include/asm/jump_label.h:20:9: note: in expansion of macro 'asm_volatile_goto'
      20 |         asm_volatile_goto(
         |         ^~~~~~~~~~~~~~~~~

vim +/asm +86 include/linux/compiler-gcc.h

313dd1b629219d Kees Cook   2017-05-05  76  
cb984d101b30eb Joe Perches 2015-06-25  77  /*
cb984d101b30eb Joe Perches 2015-06-25  78   * GCC 'asm goto' miscompiles certain code sequences:
cb984d101b30eb Joe Perches 2015-06-25  79   *
cb984d101b30eb Joe Perches 2015-06-25  80   *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
cb984d101b30eb Joe Perches 2015-06-25  81   *
cb984d101b30eb Joe Perches 2015-06-25  82   * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
cb984d101b30eb Joe Perches 2015-06-25  83   *
cb984d101b30eb Joe Perches 2015-06-25  84   * (asm goto is automatically volatile - the naming reflects this.)
cb984d101b30eb Joe Perches 2015-06-25  85   */

cb984d101b30eb Joe Perches 2015-06-25 @86 #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
cb984d101b30eb Joe Perches 2015-06-25 87

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

kernel test robot

build bot

2022-01-14 19:16 UTC #5 lore raw

Re: [PATCH v3 3/3] dmaengine: sf-pdma: Get number of channel by device tree

In reply to Zong Li

Thank you for the patch! Yet something to improve:

Hi Zong,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on vkoul-dmaengine/next]
[also build test ERROR on v5.16]
[cannot apply to robh/for-next next-20220114]
[If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Zong-Li/Determine-the-number-of-DMA-channels-by-dma-channels-property/20220114-172017
base:   https://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine.git next
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20220115/202201150313.YDVezSOq-lkp(a)intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/efa33512fd463fd6e29750992df1d40513eb5a7c
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Zong-Li/Determine-the-number-of-DMA-channels-by-dma-channels-property/20220114-172017
        git checkout efa33512fd463fd6e29750992df1d40513eb5a7c
        # save the config file to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate

Reported-by kernel test robot <[email protected]>

All error/warnings (new ones prefixed by >>):

In file included from include/linux/compiler_types.h:85,
from <command-line>:
arch/x86/include/asm/jump_label.h: In function 'vchan_cookie_complete':

>> include/linux/compiler-gcc.h:86:38: warning: asm operand 0 probably doesn't match constraints
      86 | #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
         |                                      ^~~
   arch/x86/include/asm/jump_label.h:27:2: note: in expansion of macro 'asm_volatile_goto'
      27 |  asm_volatile_goto("1:"
         |  ^~~~~~~~~~~~~~~~~
   include/linux/compiler-gcc.h:86:38: warning: asm operand 1 probably doesn't match constraints
      86 | #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
         |                                      ^~~
   arch/x86/include/asm/jump_label.h:27:2: note: in expansion of macro 'asm_volatile_goto'
      27 |  asm_volatile_goto("1:"
         |  ^~~~~~~~~~~~~~~~~
>> include/linux/compiler-gcc.h:86:38: error: impossible constraint in 'asm'
      86 | #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
         |                                      ^~~
   arch/x86/include/asm/jump_label.h:27:2: note: in expansion of macro 'asm_volatile_goto'
      27 |  asm_volatile_goto("1:"
         |  ^~~~~~~~~~~~~~~~~

vim +/asm +86 include/linux/compiler-gcc.h

313dd1b629219d Kees Cook   2017-05-05  76  
cb984d101b30eb Joe Perches 2015-06-25  77  /*
cb984d101b30eb Joe Perches 2015-06-25  78   * GCC 'asm goto' miscompiles certain code sequences:
cb984d101b30eb Joe Perches 2015-06-25  79   *
cb984d101b30eb Joe Perches 2015-06-25  80   *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
cb984d101b30eb Joe Perches 2015-06-25  81   *
cb984d101b30eb Joe Perches 2015-06-25  82   * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
cb984d101b30eb Joe Perches 2015-06-25  83   *
cb984d101b30eb Joe Perches 2015-06-25  84   * (asm goto is automatically volatile - the naming reflects this.)
cb984d101b30eb Joe Perches 2015-06-25  85   */

cb984d101b30eb Joe Perches 2015-06-25 @86 #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
cb984d101b30eb Joe Perches 2015-06-25 87

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

Zong Li

author

2022-01-17 01:29 UTC #6 lore raw

Re: [PATCH v3 3/3] dmaengine: sf-pdma: Get number of channel by device tree

Quoted 45 lines · kernel test robot

Hi Zong,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on vkoul-dmaengine/next]
[also build test ERROR on v5.16]
[cannot apply to robh/for-next next-20220114]
[If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url:    https://github.com/0day-ci/linux/commits/Zong-Li/Determine-the-number-of-DMA-channels-by-dma-channels-property/20220114-172017
base:   https://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine.git next
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20220115/202201150313.YDVezSOq-lkp(a)intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/efa33512fd463fd6e29750992df1d40513eb5a7c
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Zong-Li/Determine-the-number-of-DMA-channels-by-dma-channels-property/20220114-172017
        git checkout efa33512fd463fd6e29750992df1d40513eb5a7c
        # save the config file to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by kernel test robot <[email protected]>
All error/warnings (new ones prefixed by >>):
In file included from include/linux/compiler_types.h:85,
from <command-line>:
arch/x86/include/asm/jump_label.h: In function 'vchan_cookie_complete':
Quoted 1 line
Quoted 1 line
include/linux/compiler-gcc.h:86:38: warning: asm operand 0 probably doesn't match constraints
      86 | #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
         |                                      ^~~
   arch/x86/include/asm/jump_label.h:27:2: note: in expansion of macro 'asm_volatile_goto'
      27 |  asm_volatile_goto("1:"
         |  ^~~~~~~~~~~~~~~~~
   include/linux/compiler-gcc.h:86:38: warning: asm operand 1 probably doesn't match constraints
      86 | #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
         |                                      ^~~
   arch/x86/include/asm/jump_label.h:27:2: note: in expansion of macro 'asm_volatile_goto'
      27 |  asm_volatile_goto("1:"
         |  ^~~~~~~~~~~~~~~~~

Quoted 7 lines

Quoted 1 line

Quoted 1 line
include/linux/compiler-gcc.h:86:38: error: impossible constraint in 'asm'

      86 | #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
         |                                      ^~~
   arch/x86/include/asm/jump_label.h:27:2: note: in expansion of macro 'asm_volatile_goto'
      27 |  asm_volatile_goto("1:"
         |  ^~~~~~~~~~~~~~~~~

I have fixed it in the next version, the previous patch mis included my debug cflags in Makefile.

Quoted 19 lines

vim +/asm +86 include/linux/compiler-gcc.h
313dd1b629219d Kees Cook   2017-05-05  76
cb984d101b30eb Joe Perches 2015-06-25  77  /*
cb984d101b30eb Joe Perches 2015-06-25  78   * GCC 'asm goto' miscompiles certain code sequences:
cb984d101b30eb Joe Perches 2015-06-25  79   *
cb984d101b30eb Joe Perches 2015-06-25  80   *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
cb984d101b30eb Joe Perches 2015-06-25  81   *
cb984d101b30eb Joe Perches 2015-06-25  82   * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
cb984d101b30eb Joe Perches 2015-06-25  83   *
cb984d101b30eb Joe Perches 2015-06-25  84   * (asm goto is automatically volatile - the naming reflects this.)
cb984d101b30eb Joe Perches 2015-06-25  85   */
cb984d101b30eb Joe Perches 2015-06-25 @86 #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
cb984d101b30eb Joe Perches 2015-06-25 87
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org