| Message ID | 20220826144341.532265-4-weiyongjun1@huawei.com |
|---|---|
| State | New |
| Headers | show |
| Series | spi: Introduce BPF based SPI mockup controller | expand |
comment inline below, plus adding to cc: and to: list On 8/26/22 09:43, Wei Yongjun wrote: > Add a runtime device tree overlay interface for device need dts file. > With it its possible to use device tree overlays without having to use > a per-platform overlay manager. Why is an overlay needed? The documentation in patch 4 shows providing a dtb as an argument to the qemu-system-x86_64 command, which should be sufficient to supply the appropriate dtb. -Frank > > Add a new device by command: > $ cat test.dtbo > /sys/class/spi_master/spi0/overlay_fdto > > Remove the device by command: > $ echo remove > /sys/class/spi_master/spi0/overlay_fdto > > Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> > --- > drivers/spi/Kconfig | 2 ++ > drivers/spi/spi-mockup.c | 48 ++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 50 insertions(+) > > diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig > index e0f0fa2746ad..4b7c84ddb367 100644 > --- a/drivers/spi/Kconfig > +++ b/drivers/spi/Kconfig > @@ -1161,6 +1161,8 @@ config SPI_TLE62X0 > config SPI_MOCKUP > tristate "SPI controller Testing Driver" > depends on OF > + select OF_EARLY_FLATTREE > + select OF_RESOLVE > select BPF_EVENTS > help > This enables SPI controller testing driver, which provides a way to > diff --git a/drivers/spi/spi-mockup.c b/drivers/spi/spi-mockup.c > index 7a93b194ee53..404ad821bf6a 100644 > --- a/drivers/spi/spi-mockup.c > +++ b/drivers/spi/spi-mockup.c > @@ -21,6 +21,9 @@ > struct mockup_spi { > struct mutex lock; > struct spi_device *devs[MOCKUP_CHIPSELECT_MAX]; > + > + void *fdto; > + int ovcs_id; > }; > > static struct spi_master *to_spi_master(struct device *dev) > @@ -145,9 +148,53 @@ delete_device_store(struct device *dev, struct device_attribute *attr, > } > static DEVICE_ATTR_WO(delete_device); > > +static ssize_t > +overlay_fdto_store(struct device *dev, struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct spi_master *master = to_spi_master(dev); > + struct mockup_spi *mock = spi_master_get_devdata(master); > + int ret; > + > + mutex_lock(&mock->lock); > + > + if (strncmp(buf, "remove\n", count) == 0) { > + if (mock->ovcs_id < 0) { > + ret = -ENOENT; > + goto out_unlock; > + } > + of_overlay_remove(&mock->ovcs_id); > + kfree(mock->fdto); > + mock->ovcs_id = -1; > + mock->fdto = NULL; > + } else { > + if (mock->ovcs_id >= 0) { > + ret = -EINVAL; > + goto out_unlock; > + } > + mock->fdto = kmemdup(buf, count, GFP_KERNEL); > + if (!mock->fdto) { > + ret = -ENOMEM; > + goto out_unlock; > + } > + ret = of_overlay_fdt_apply(mock->fdto, count, &mock->ovcs_id); > + if (ret < 0) > + goto out_unlock; > + } > + > + mutex_unlock(&mock->lock); > + return count; > + > +out_unlock: > + mutex_unlock(&mock->lock); > + return ret; > +} > +static DEVICE_ATTR_WO(overlay_fdto); > + > static struct attribute *spi_mockup_attrs[] = { > &dev_attr_new_device.attr, > &dev_attr_delete_device.attr, > + &dev_attr_overlay_fdto.attr, > NULL > }; > ATTRIBUTE_GROUPS(spi_mockup); > @@ -227,6 +274,7 @@ static int spi_mockup_probe(struct platform_device *pdev) > > mock = spi_master_get_devdata(master); > mutex_init(&mock->lock); > + mock->ovcs_id = -1; > > ret = spi_register_master(master); > if (ret) {
On 2022/8/30 5:29, Frank Rowand wrote: > comment inline below, plus adding to cc: and to: list > > On 8/26/22 09:43, Wei Yongjun wrote: >> Add a runtime device tree overlay interface for device need dts file. >> With it its possible to use device tree overlays without having to use >> a per-platform overlay manager. > > Why is an overlay needed? The documentation in patch 4 shows providing > a dtb as an argument to the qemu-system-x86_64 command, which should be > sufficient to supply the appropriate dtb. Fist, we are aimed to build a device driver regression testsuit. Without overlay, lots of the dtb fragments must be combined to a very big one, it may different to maintainence. overlay makes easily to attach/detech as the device's requirement. Seconds, overlay dts may be used to found or verification issues related to of_node_put or others, such as patches like: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/log/?qt=grep&q=node_put many of them may found by static check tool, which may leak of tesing. The documentation I post does not use overlay dts, but when overlay dts[1] is used, we can found the of node leak: $ python3 -m kddv.cmds.mock -b spi -d mchp23k256 create spi device mchp23k256 success! $ ls /sys/bus/spi/drivers/mchp23k256/spi0.0/mtd/ mtd0 mtd0ro $ python3 -m kddv.cmds.mock -b spi -d mchp23k256 -r [ 233.508565] Deleting MTD partitions on "spi0.0": [ 233.516784] OF: ERROR: memory leak, expected refcount 1 instead of 2, of_node_get()/of_node_put() unbalanced - destroy cset entry: attach overlay node /spi/spi-sram@0 remove spi device mchp23k256 success! Not sure it is worth to fix issues like this, but at least, we can tesing them now. -[1]--------------------------------------------------------- /dts-v1/; /plugin/; &{/spi} { spi-sram@0 { #address-cells = <1>; #size-cells = <1>; compatible = "microchip,mchp23k256"; reg = <0>; spi-max-frequency = <20000000>; }; }; ------------------------------------------------------- Regards, Wei Yongjun > > -Frank > >> >> Add a new device by command: >> $ cat test.dtbo > /sys/class/spi_master/spi0/overlay_fdto >> >> Remove the device by command: >> $ echo remove > /sys/class/spi_master/spi0/overlay_fdto >> >> Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> >> --- >> drivers/spi/Kconfig | 2 ++ >> drivers/spi/spi-mockup.c | 48 ++++++++++++++++++++++++++++++++++++++++ >> 2 files changed, 50 insertions(+) >> >> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig >> index e0f0fa2746ad..4b7c84ddb367 100644 >> --- a/drivers/spi/Kconfig >> +++ b/drivers/spi/Kconfig >> @@ -1161,6 +1161,8 @@ config SPI_TLE62X0 >> config SPI_MOCKUP >> tristate "SPI controller Testing Driver" >> depends on OF >> + select OF_EARLY_FLATTREE >> + select OF_RESOLVE >> select BPF_EVENTS >> help >> This enables SPI controller testing driver, which provides a way to >> diff --git a/drivers/spi/spi-mockup.c b/drivers/spi/spi-mockup.c >> index 7a93b194ee53..404ad821bf6a 100644 >> --- a/drivers/spi/spi-mockup.c >> +++ b/drivers/spi/spi-mockup.c >> @@ -21,6 +21,9 @@ >> struct mockup_spi { >> struct mutex lock; >> struct spi_device *devs[MOCKUP_CHIPSELECT_MAX]; >> + >> + void *fdto; >> + int ovcs_id; >> }; >> >> static struct spi_master *to_spi_master(struct device *dev) >> @@ -145,9 +148,53 @@ delete_device_store(struct device *dev, struct device_attribute *attr, >> } >> static DEVICE_ATTR_WO(delete_device); >> >> +static ssize_t >> +overlay_fdto_store(struct device *dev, struct device_attribute *attr, >> + const char *buf, size_t count) >> +{ >> + struct spi_master *master = to_spi_master(dev); >> + struct mockup_spi *mock = spi_master_get_devdata(master); >> + int ret; >> + >> + mutex_lock(&mock->lock); >> + >> + if (strncmp(buf, "remove\n", count) == 0) { >> + if (mock->ovcs_id < 0) { >> + ret = -ENOENT; >> + goto out_unlock; >> + } >> + of_overlay_remove(&mock->ovcs_id); >> + kfree(mock->fdto); >> + mock->ovcs_id = -1; >> + mock->fdto = NULL; >> + } else { >> + if (mock->ovcs_id >= 0) { >> + ret = -EINVAL; >> + goto out_unlock; >> + } >> + mock->fdto = kmemdup(buf, count, GFP_KERNEL); >> + if (!mock->fdto) { >> + ret = -ENOMEM; >> + goto out_unlock; >> + } >> + ret = of_overlay_fdt_apply(mock->fdto, count, &mock->ovcs_id); >> + if (ret < 0) >> + goto out_unlock; >> + } >> + >> + mutex_unlock(&mock->lock); >> + return count; >> + >> +out_unlock: >> + mutex_unlock(&mock->lock); >> + return ret; >> +} >> +static DEVICE_ATTR_WO(overlay_fdto); >> + >> static struct attribute *spi_mockup_attrs[] = { >> &dev_attr_new_device.attr, >> &dev_attr_delete_device.attr, >> + &dev_attr_overlay_fdto.attr, >> NULL >> }; >> ATTRIBUTE_GROUPS(spi_mockup); >> @@ -227,6 +274,7 @@ static int spi_mockup_probe(struct platform_device *pdev) >> >> mock = spi_master_get_devdata(master); >> mutex_init(&mock->lock); >> + mock->ovcs_id = -1; >> >> ret = spi_register_master(master); >> if (ret) { >
On Fri, Aug 26, 2022 at 02:43:40PM +0000, Wei Yongjun wrote: > Add a runtime device tree overlay interface for device need dts file. > With it its possible to use device tree overlays without having to use > a per-platform overlay manager. Why would an entirely virtual device like this need to appear in DT? DT is supposed to be a hardware description and this clearly isn't hardware, nor is it something we're providing to a VM.
On 8/30/22 05:27, Mark Brown wrote: > On Fri, Aug 26, 2022 at 02:43:40PM +0000, Wei Yongjun wrote: > >> Add a runtime device tree overlay interface for device need dts file. >> With it its possible to use device tree overlays without having to use >> a per-platform overlay manager. > > Why would an entirely virtual device like this need to appear in > DT? DT is supposed to be a hardware description and this clearly > isn't hardware, nor is it something we're providing to a VM. Good point. Patch 3 seems to not be needed. -Frank
On 2022/8/31 3:24, Frank Rowand wrote: > On 8/30/22 05:27, Mark Brown wrote: >> On Fri, Aug 26, 2022 at 02:43:40PM +0000, Wei Yongjun wrote: >> >>> Add a runtime device tree overlay interface for device need dts file. >>> With it its possible to use device tree overlays without having to use >>> a per-platform overlay manager. >> >> Why would an entirely virtual device like this need to appear in >> DT? DT is supposed to be a hardware description and this clearly >> isn't hardware, nor is it something we're providing to a VM. > > Good point. Patch 3 seems to not be needed. Yes, will drop it in next version. Thanks, Wei Yongjun
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index e0f0fa2746ad..4b7c84ddb367 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -1161,6 +1161,8 @@ config SPI_TLE62X0 config SPI_MOCKUP tristate "SPI controller Testing Driver" depends on OF + select OF_EARLY_FLATTREE + select OF_RESOLVE select BPF_EVENTS help This enables SPI controller testing driver, which provides a way to diff --git a/drivers/spi/spi-mockup.c b/drivers/spi/spi-mockup.c index 7a93b194ee53..404ad821bf6a 100644 --- a/drivers/spi/spi-mockup.c +++ b/drivers/spi/spi-mockup.c @@ -21,6 +21,9 @@ struct mockup_spi { struct mutex lock; struct spi_device *devs[MOCKUP_CHIPSELECT_MAX]; + + void *fdto; + int ovcs_id; }; static struct spi_master *to_spi_master(struct device *dev) @@ -145,9 +148,53 @@ delete_device_store(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR_WO(delete_device); +static ssize_t +overlay_fdto_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct spi_master *master = to_spi_master(dev); + struct mockup_spi *mock = spi_master_get_devdata(master); + int ret; + + mutex_lock(&mock->lock); + + if (strncmp(buf, "remove\n", count) == 0) { + if (mock->ovcs_id < 0) { + ret = -ENOENT; + goto out_unlock; + } + of_overlay_remove(&mock->ovcs_id); + kfree(mock->fdto); + mock->ovcs_id = -1; + mock->fdto = NULL; + } else { + if (mock->ovcs_id >= 0) { + ret = -EINVAL; + goto out_unlock; + } + mock->fdto = kmemdup(buf, count, GFP_KERNEL); + if (!mock->fdto) { + ret = -ENOMEM; + goto out_unlock; + } + ret = of_overlay_fdt_apply(mock->fdto, count, &mock->ovcs_id); + if (ret < 0) + goto out_unlock; + } + + mutex_unlock(&mock->lock); + return count; + +out_unlock: + mutex_unlock(&mock->lock); + return ret; +} +static DEVICE_ATTR_WO(overlay_fdto); + static struct attribute *spi_mockup_attrs[] = { &dev_attr_new_device.attr, &dev_attr_delete_device.attr, + &dev_attr_overlay_fdto.attr, NULL }; ATTRIBUTE_GROUPS(spi_mockup); @@ -227,6 +274,7 @@ static int spi_mockup_probe(struct platform_device *pdev) mock = spi_master_get_devdata(master); mutex_init(&mock->lock); + mock->ovcs_id = -1; ret = spi_register_master(master); if (ret) {
Add a runtime device tree overlay interface for device need dts file. With it its possible to use device tree overlays without having to use a per-platform overlay manager. Add a new device by command: $ cat test.dtbo > /sys/class/spi_master/spi0/overlay_fdto Remove the device by command: $ echo remove > /sys/class/spi_master/spi0/overlay_fdto Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> --- drivers/spi/Kconfig | 2 ++ drivers/spi/spi-mockup.c | 48 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 50 insertions(+)