This is the first time I'm interacting with the Linux mailing lists, so
please don't eviscerate me *too much* if I get the formatting wrong.
Of course I'm always willing to take criticism and improve my formatting
in the future.
This patch adds support for IRQs to the PASemi I2C controller driver.
This will allow for faster performing I2C transactions on Apple Silicon
hardware, as previously, the driver was forced to poll the SMSTA register
for a set amount of time.
With this patchset the driver on Apple silicon hardware will instead wait
for an interrupt which will signal the completion of the I2C transaction.
The timeout value for this completion will be the same as the current
amount of time the I2C driver polls for.
This will result in some performance improvement since the driver will be
waiting for less time than it does right now on Apple Silicon hardware.
The patch right now will only enable IRQs for Apple Silicon I2C chips,
and only if it's able to successfully request the IRQ from the kernel.
=== Testing ===
This patch has been tested on both the mainline Linux kernel tree and
the Asahi branch (https://github.com/AsahiLinux/linux.git) on both an
M1 and M2 MacBook Air, and it compiles successfully as both a module and
built-in to the kernel itself. The patch in both trees successfully boots
to userspace without any hitch.
I do not have PASemi hardware on hand unfortunately, so I'm unable to test
the impact of this patch on old PASemi hardware. This is also why I've
elected to do the IRQ request and enablement on the Apple platform driver
and not in the common file, as I'm not sure if PASemi hardware supports
IRQs.
I also fixed a quick checkpatch warning on line 303. "i ++" is now "i++".
Any and all critiques of the patch would be well appreciated.
Signed-off-by: Arminder Singh <redacted>
---
drivers/i2c/busses/i2c-pasemi-core.c | 29 ++++++++++++++++++++----
drivers/i2c/busses/i2c-pasemi-core.h | 5 ++++
drivers/i2c/busses/i2c-pasemi-platform.c | 8 +++++++
3 files changed, 37 insertions(+), 5 deletions(-)
From: kernel test robot <hidden> Date: 2022-08-20 21:40:33
Hi Arminder,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on powerpc/next]
[also build test WARNING on linus/master v6.0-rc1 next-20220819]
[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#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Arminder-Singh/i2c-pasemi-Add-IRQ-support-for-Apple-Silicon/20220821-034703
base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: riscv-randconfig-r042-20220821 (https://download.01.org/0day-ci/archive/20220821/202208210548.MCoIwyQl-lkp@intel.com/config)
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project c9a41fe60ab62f7a40049c100adcc8087a47669b)
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
# install riscv cross compiling tool for clang build
# apt-get install binutils-riscv64-linux-gnu
# https://github.com/intel-lab-lkp/linux/commit/98584b2b51d808ab582798c7a50511e8c1889ced
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Arminder-Singh/i2c-pasemi-Add-IRQ-support-for-Apple-Silicon/20220821-034703
git checkout 98584b2b51d808ab582798c7a50511e8c1889ced
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash drivers/i2c/busses/
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <redacted>
All warnings (new ones prefixed by >>):
In file included from drivers/i2c/busses/i2c-pasemi-core.c:9:
In file included from include/linux/pci.h:38:
In file included from include/linux/interrupt.h:11:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/riscv/include/asm/io.h:136:
include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __raw_readb(PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
#define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
^
In file included from drivers/i2c/busses/i2c-pasemi-core.c:9:
In file included from include/linux/pci.h:38:
In file included from include/linux/interrupt.h:11:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/riscv/include/asm/io.h:136:
include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
#define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
^
In file included from drivers/i2c/busses/i2c-pasemi-core.c:9:
In file included from include/linux/pci.h:38:
In file included from include/linux/interrupt.h:11:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/riscv/include/asm/io.h:136:
include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writeb(value, PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:1134:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
~~~~~~~~~~ ^
quoted
drivers/i2c/busses/i2c-pasemi-core.c:86:6: warning: variable 'status' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
if (smbus->use_irq) {
^~~~~~~~~~~~~~
drivers/i2c/busses/i2c-pasemi-core.c:92:12: note: uninitialized use occurs here
while (!(status & SMSTA_XEN) && timeout--) {
^~~~~~
drivers/i2c/busses/i2c-pasemi-core.c:86:2: note: remove the 'if' if its condition is always true
if (smbus->use_irq) {
^~~~~~~~~~~~~~~~~~~~
drivers/i2c/busses/i2c-pasemi-core.c:83:21: note: initialize the variable 'status' to silence this warning
unsigned int status;
^
= 0
8 warnings generated.
vim +86 drivers/i2c/busses/i2c-pasemi-core.c
79
80 static int pasemi_smb_waitready(struct pasemi_smbus *smbus)
81 {
82 int timeout = 10;
83 unsigned int status;
84 unsigned int bitmask = SMSTA_XEN | SMSTA_MTN;
85
> 86 if (smbus->use_irq) {
87 reinit_completion(&smbus->irq_completion);
88 reg_write(smbus, REG_IMASK, bitmask);
89 wait_for_completion_timeout(&smbus->irq_completion, msecs_to_jiffies(10));
90 status = reg_read(smbus, REG_SMSTA);
91 } else {
92 while (!(status & SMSTA_XEN) && timeout--) {
93 msleep(1);
94 status = reg_read(smbus, REG_SMSTA);
95 }
96 }
97
98
99 /* Got NACK? */
100 if (status & SMSTA_MTN)
101 return -ENXIO;
102
103 if (timeout < 0) {
104 dev_warn(smbus->dev, "Timeout, status 0x%08x\n", status);
105 reg_write(smbus, REG_SMSTA, status);
106 return -ETIME;
107 }
108
109 /* Clear XEN */
110 reg_write(smbus, REG_SMSTA, SMSTA_XEN);
111
112 return 0;
113 }
114
--
0-DAY CI Kernel Test Service
https://01.org/lkp
This is the first time I'm interacting with the Linux mailing lists, so
please don't eviscerate me *too much* if I get the formatting wrong.
Of course I'm always willing to take criticism and improve my formatting
in the future.
The above text should go after you signed-off-by, after the --- , so
that it get's ignored by 'git am' when applying.
This patch adds support for IRQs to the PASemi I2C controller driver.
This will allow for faster performing I2C transactions on Apple Silicon
hardware, as previously, the driver was forced to poll the SMSTA register
for a set amount of time.
With this patchset the driver on Apple silicon hardware will instead wait
for an interrupt which will signal the completion of the I2C transaction.
The timeout value for this completion will be the same as the current
amount of time the I2C driver polls for.
This will result in some performance improvement since the driver will be
waiting for less time than it does right now on Apple Silicon hardware.
The patch right now will only enable IRQs for Apple Silicon I2C chips,
and only if it's able to successfully request the IRQ from the kernel.
=== Testing ===
This patch has been tested on both the mainline Linux kernel tree and
the Asahi branch (https://github.com/AsahiLinux/linux.git) on both an
M1 and M2 MacBook Air, and it compiles successfully as both a module and
built-in to the kernel itself. The patch in both trees successfully boots
to userspace without any hitch.
I do not have PASemi hardware on hand unfortunately, so I'm unable to test
the impact of this patch on old PASemi hardware. This is also why I've
elected to do the IRQ request and enablement on the Apple platform driver
and not in the common file, as I'm not sure if PASemi hardware supports
IRQs.
I also fixed a quick checkpatch warning on line 303. "i ++" is now "i++".
Any and all critiques of the patch would be well appreciated.
That as well shouldn't be part of the commit message.
status is uninitialised when entering the while loop.
+ while (!(status & SMSTA_XEN) && timeout--) {
+ msleep(1);
+ status = reg_read(smbus, REG_SMSTA);
+ }
}
+
Why a second blank line here ?
quoted hunk
/* Got NACK? */
if (status & SMSTA_MTN)
return -ENXIO;
@@ -300,7 +308,7 @@ static int pasemi_smb_xfer(struct i2c_adapter *adapter, case I2C_SMBUS_BLOCK_DATA: case I2C_SMBUS_BLOCK_PROC_CALL: data->block[0] = len;- for (i = 1; i <= len; i ++) {+ for (i = 1; i <= len; i++) {
This shouldn't be part of this patch, it is unrelated.
From: Sven Peter <hidden> Date: 2022-08-21 09:57:34
Hi,
Thanks for the patch! Some additional comments:
On Sat, Aug 20, 2022, at 21:45, Arminder Singh wrote:
quoted hunk
This is the first time I'm interacting with the Linux mailing lists, so
please don't eviscerate me *too much* if I get the formatting wrong.
Of course I'm always willing to take criticism and improve my formatting
in the future.
This patch adds support for IRQs to the PASemi I2C controller driver.
This will allow for faster performing I2C transactions on Apple Silicon
hardware, as previously, the driver was forced to poll the SMSTA register
for a set amount of time.
With this patchset the driver on Apple silicon hardware will instead wait
for an interrupt which will signal the completion of the I2C transaction.
The timeout value for this completion will be the same as the current
amount of time the I2C driver polls for.
This will result in some performance improvement since the driver will be
waiting for less time than it does right now on Apple Silicon hardware.
The patch right now will only enable IRQs for Apple Silicon I2C chips,
and only if it's able to successfully request the IRQ from the kernel.
=== Testing ===
This patch has been tested on both the mainline Linux kernel tree and
the Asahi branch (https://github.com/AsahiLinux/linux.git) on both an
M1 and M2 MacBook Air, and it compiles successfully as both a module and
built-in to the kernel itself. The patch in both trees successfully boots
to userspace without any hitch.
I do not have PASemi hardware on hand unfortunately, so I'm unable to test
the impact of this patch on old PASemi hardware. This is also why I've
elected to do the IRQ request and enablement on the Apple platform driver
and not in the common file, as I'm not sure if PASemi hardware supports
IRQs.
I also fixed a quick checkpatch warning on line 303. "i ++" is now "i++".
Any and all critiques of the patch would be well appreciated.
Signed-off-by: Arminder Singh <redacted>
---
drivers/i2c/busses/i2c-pasemi-core.c | 29 ++++++++++++++++++++----
drivers/i2c/busses/i2c-pasemi-core.h | 5 ++++
drivers/i2c/busses/i2c-pasemi-platform.c | 8 +++++++
3 files changed, 37 insertions(+), 5 deletions(-)
diff --git a/drivers/i2c/busses/i2c-pasemi-core.c
b/drivers/i2c/busses/i2c-pasemi-core.c
index 9028ffb58cc0..375aa9528233 100644
@@ -80,14 +81,21 @@ static int pasemi_smb_waitready(struct pasemi_smbus *smbus){inttimeout=10;unsignedintstatus;+unsignedintbitmask=SMSTA_XEN|SMSTA_MTN;-status=reg_read(smbus,REG_SMSTA);--while(!(status&SMSTA_XEN)&&timeout--){-msleep(1);+if(smbus->use_irq){+reinit_completion(&smbus->irq_completion);+reg_write(smbus,REG_IMASK,bitmask);
s/bitmask/SMSTA_XEN | SMSTA_MTN/ and then you can just drop the bitmask
variable which isn't used anywhere else.
+ wait_for_completion_timeout(&smbus->irq_completion, msecs_to_jiffies(10));
status = reg_read(smbus, REG_SMSTA);
If the irq hasn't fired and wait_for_completion_timeout timed out the irq
is still enabled here. I'd put a reg_write(smbus, REG_IMASK, 0); here
to be safe.
+ } else {
You also need status = reg_read(smbus, REG_SMSTA); here.
quoted hunk
+ while (!(status & SMSTA_XEN) && timeout--) {
+ msleep(1);
+ status = reg_read(smbus, REG_SMSTA);
+ }
}
+
/* Got NACK? */
if (status & SMSTA_MTN)
return -ENXIO;
@@ -300,7 +308,7 @@ static int pasemi_smb_xfer(struct i2c_adapter *adapter, case I2C_SMBUS_BLOCK_DATA: case I2C_SMBUS_BLOCK_PROC_CALL: data->block[0] = len;- for (i = 1; i <= len; i ++) {+ for (i = 1; i <= len; i++) { rd = RXFIFO_RD(smbus); if (rd & MRXFIFO_EMPTY) { err = -ENODATA;
If you use request_irq here you'll have to add a remove function and
call free_irq there. I'd just use devm_request_irq which takes care of
that automatically.
From: Michael Ellerman <mpe@ellerman.id.au> Date: 2022-08-23 01:50:39
Arminder Singh [off-list ref] writes:
This is the first time I'm interacting with the Linux mailing lists, so
please don't eviscerate me *too much* if I get the formatting wrong.
Of course I'm always willing to take criticism and improve my formatting
in the future.
This patch adds support for IRQs to the PASemi I2C controller driver.
This will allow for faster performing I2C transactions on Apple Silicon
hardware, as previously, the driver was forced to poll the SMSTA register
for a set amount of time.
With this patchset the driver on Apple silicon hardware will instead wait
for an interrupt which will signal the completion of the I2C transaction.
The timeout value for this completion will be the same as the current
amount of time the I2C driver polls for.
This will result in some performance improvement since the driver will be
waiting for less time than it does right now on Apple Silicon hardware.
The patch right now will only enable IRQs for Apple Silicon I2C chips,
and only if it's able to successfully request the IRQ from the kernel.
=== Testing ===
This patch has been tested on both the mainline Linux kernel tree and
the Asahi branch (https://github.com/AsahiLinux/linux.git) on both an
M1 and M2 MacBook Air, and it compiles successfully as both a module and
built-in to the kernel itself. The patch in both trees successfully boots
to userspace without any hitch.
I do not have PASemi hardware on hand unfortunately, so I'm unable to test
the impact of this patch on old PASemi hardware. This is also why I've
elected to do the IRQ request and enablement on the Apple platform driver
and not in the common file, as I'm not sure if PASemi hardware supports
IRQs.
I've added Darren and Christian to Cc, they have helped with PASemi
development and testing in the past, and may be able to help test this
series on PASemi hardware.
cheers
On Sat, Aug 20, 2022 at 9:45 PM Arminder Singh [off-list ref] wrote:
I also fixed a quick checkpatch warning on line 303. "i ++" is now "i++".
In general, anything that is mentioned in the changelog as "also done this"
is worth splitting into a separate patch, or dropping from the patch, to
make reviewing easier.
In this case, I would just not do the trivial change. Alternatively you
can consider doing a larger patch for coding style cleanup on the
patch, as there are possibly other issues as well. Usually it's not worth
changing things unless they hurt readability.
quoted hunk
@@ -80,14 +81,21 @@ static int pasemi_smb_waitready(struct pasemi_smbus *smbus) { int timeout = 10; unsigned int status;+ unsigned int bitmask = SMSTA_XEN | SMSTA_MTN;+ if (smbus->use_irq) {+ reinit_completion(&smbus->irq_completion);+ reg_write(smbus, REG_IMASK, bitmask);+ wait_for_completion_timeout(&smbus->irq_completion, msecs_to_jiffies(10)); status = reg_read(smbus, REG_SMSTA); }+ /* Got NACK? */ if (status & SMSTA_MTN) return -ENXIO;
I think the completion structure gets out of sync if you run into a
timeout here,
so a subsequent wait_for_completion will never complete after we missed one
interrupt.
Since this already causes a bus reset, I think you can just do
reinit_completion() at the end of pasemi_reset() to avoid this.
Arnd
From: Christian Zigotzky <hidden> Date: 2022-08-25 14:46:51
On 23 August 2022 at 03:50 am, Michael Ellerman wrote:
Arminder Singh [off-list ref] writes:
quoted
This is the first time I'm interacting with the Linux mailing lists, so
please don't eviscerate me *too much* if I get the formatting wrong.
Of course I'm always willing to take criticism and improve my formatting
in the future.
This patch adds support for IRQs to the PASemi I2C controller driver.
This will allow for faster performing I2C transactions on Apple Silicon
hardware, as previously, the driver was forced to poll the SMSTA register
for a set amount of time.
With this patchset the driver on Apple silicon hardware will instead wait
for an interrupt which will signal the completion of the I2C transaction.
The timeout value for this completion will be the same as the current
amount of time the I2C driver polls for.
This will result in some performance improvement since the driver will be
waiting for less time than it does right now on Apple Silicon hardware.
The patch right now will only enable IRQs for Apple Silicon I2C chips,
and only if it's able to successfully request the IRQ from the kernel.
=== Testing ===
This patch has been tested on both the mainline Linux kernel tree and
the Asahi branch (https://github.com/AsahiLinux/linux.git) on both an
M1 and M2 MacBook Air, and it compiles successfully as both a module and
built-in to the kernel itself. The patch in both trees successfully boots
to userspace without any hitch.
I do not have PASemi hardware on hand unfortunately, so I'm unable to test
the impact of this patch on old PASemi hardware. This is also why I've
elected to do the IRQ request and enablement on the Apple platform driver
and not in the common file, as I'm not sure if PASemi hardware supports
IRQs.
I've added Darren and Christian to Cc, they have helped with PASemi
development and testing in the past, and may be able to help test this
series on PASemi hardware.
cheers
Tested-by: Christian Zigotzky <chzigotzky at xenosoft.de>
on an A-EON AmigaOne X1000 with a PASemi PWRficient PA6T-1682 processor.