| Message ID | 20220809223401.24599-4-mike.leach@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | coresight: Add new API to allocate trace source ID values | expand |
On 09/08/2022 23:33, Mike Leach wrote: > Updates the STM driver to use the trace ID allocation API. > This uses the _system_id calls to allocate an ID on device poll, > and release on device remove. > > The sysfs access to the STMTRACEIDR register has been changed from RW > to RO. Having this value as writable is not appropriate for the new > Trace ID scheme - and had potential to cause errors in the previous > scheme if values clashed with other sources. > > Signed-off-by: Mike Leach <mike.leach@linaro.org> > Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > drivers/hwtracing/coresight/coresight-stm.c | 41 +++++++-------------- > 1 file changed, 14 insertions(+), 27 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c > index bb14a3a8a921..9ef3e923a930 100644 > --- a/drivers/hwtracing/coresight/coresight-stm.c > +++ b/drivers/hwtracing/coresight/coresight-stm.c > @@ -31,6 +31,7 @@ > #include <linux/stm.h> > > #include "coresight-priv.h" > +#include "coresight-trace-id.h" > > #define STMDMASTARTR 0xc04 > #define STMDMASTOPR 0xc08 > @@ -615,24 +616,7 @@ static ssize_t traceid_show(struct device *dev, > val = drvdata->traceid; > return sprintf(buf, "%#lx\n", val); > } > - > -static ssize_t traceid_store(struct device *dev, > - struct device_attribute *attr, > - const char *buf, size_t size) > -{ > - int ret; > - unsigned long val; > - struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent); > - > - ret = kstrtoul(buf, 16, &val); > - if (ret) > - return ret; > - > - /* traceid field is 7bit wide on STM32 */ > - drvdata->traceid = val & 0x7f; > - return size; > -} > -static DEVICE_ATTR_RW(traceid); > +static DEVICE_ATTR_RO(traceid); > > #define coresight_stm_reg(name, offset) \ > coresight_simple_reg32(struct stm_drvdata, name, offset) > @@ -819,14 +803,6 @@ static void stm_init_default_data(struct stm_drvdata *drvdata) > */ > drvdata->stmsper = ~0x0; > > - /* > - * The trace ID value for *ETM* tracers start at CPU_ID * 2 + 0x10 and > - * anything equal to or higher than 0x70 is reserved. Since 0x00 is > - * also reserved the STM trace ID needs to be higher than 0x00 and > - * lowner than 0x10. > - */ > - drvdata->traceid = 0x1; > - > /* Set invariant transaction timing on all channels */ > bitmap_clear(drvdata->chs.guaranteed, 0, drvdata->numsp); > } > @@ -854,7 +830,7 @@ static void stm_init_generic_data(struct stm_drvdata *drvdata, > > static int stm_probe(struct amba_device *adev, const struct amba_id *id) > { > - int ret; > + int ret, trace_id; > void __iomem *base; > struct device *dev = &adev->dev; > struct coresight_platform_data *pdata = NULL; > @@ -938,12 +914,22 @@ static int stm_probe(struct amba_device *adev, const struct amba_id *id) > goto stm_unregister; > } > > + trace_id = coresight_trace_id_get_system_id(); > + if (trace_id < 0) { The above API returns "INVALID_ID" and not a negative error status. I think it is better to fix the API to return: ret < 0 - If there is any error - Otherwise a positive integer And the users should be kept unaware of which ID is valid or invalid. Suzuki
Hi Suzuki, On Mon, 3 Oct 2022 at 10:04, Suzuki K Poulose <suzuki.poulose@arm.com> wrote: > > On 09/08/2022 23:33, Mike Leach wrote: > > Updates the STM driver to use the trace ID allocation API. > > This uses the _system_id calls to allocate an ID on device poll, > > and release on device remove. > > > > The sysfs access to the STMTRACEIDR register has been changed from RW > > to RO. Having this value as writable is not appropriate for the new > > Trace ID scheme - and had potential to cause errors in the previous > > scheme if values clashed with other sources. > > > > Signed-off-by: Mike Leach <mike.leach@linaro.org> > > Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> > > --- > > drivers/hwtracing/coresight/coresight-stm.c | 41 +++++++-------------- > > 1 file changed, 14 insertions(+), 27 deletions(-) > > > > diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c > > index bb14a3a8a921..9ef3e923a930 100644 > > --- a/drivers/hwtracing/coresight/coresight-stm.c > > +++ b/drivers/hwtracing/coresight/coresight-stm.c > > @@ -31,6 +31,7 @@ > > #include <linux/stm.h> > > > > #include "coresight-priv.h" > > +#include "coresight-trace-id.h" > > > > #define STMDMASTARTR 0xc04 > > #define STMDMASTOPR 0xc08 > > @@ -615,24 +616,7 @@ static ssize_t traceid_show(struct device *dev, > > val = drvdata->traceid; > > return sprintf(buf, "%#lx\n", val); > > } > > - > > -static ssize_t traceid_store(struct device *dev, > > - struct device_attribute *attr, > > - const char *buf, size_t size) > > -{ > > - int ret; > > - unsigned long val; > > - struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent); > > - > > - ret = kstrtoul(buf, 16, &val); > > - if (ret) > > - return ret; > > - > > - /* traceid field is 7bit wide on STM32 */ > > - drvdata->traceid = val & 0x7f; > > - return size; > > -} > > -static DEVICE_ATTR_RW(traceid); > > +static DEVICE_ATTR_RO(traceid); > > > > #define coresight_stm_reg(name, offset) \ > > coresight_simple_reg32(struct stm_drvdata, name, offset) > > @@ -819,14 +803,6 @@ static void stm_init_default_data(struct stm_drvdata *drvdata) > > */ > > drvdata->stmsper = ~0x0; > > > > - /* > > - * The trace ID value for *ETM* tracers start at CPU_ID * 2 + 0x10 and > > - * anything equal to or higher than 0x70 is reserved. Since 0x00 is > > - * also reserved the STM trace ID needs to be higher than 0x00 and > > - * lowner than 0x10. > > - */ > > - drvdata->traceid = 0x1; > > - > > /* Set invariant transaction timing on all channels */ > > bitmap_clear(drvdata->chs.guaranteed, 0, drvdata->numsp); > > } > > @@ -854,7 +830,7 @@ static void stm_init_generic_data(struct stm_drvdata *drvdata, > > > > static int stm_probe(struct amba_device *adev, const struct amba_id *id) > > { > > - int ret; > > + int ret, trace_id; > > void __iomem *base; > > struct device *dev = &adev->dev; > > struct coresight_platform_data *pdata = NULL; > > @@ -938,12 +914,22 @@ static int stm_probe(struct amba_device *adev, const struct amba_id *id) > > goto stm_unregister; > > } > > > > + trace_id = coresight_trace_id_get_system_id(); > > + if (trace_id < 0) { > > The above API returns "INVALID_ID" and not a negative error status. > I think it is better to fix the API to return: > > ret < 0 - If there is any error > - Otherwise a positive integer > And the users should be kept unaware of which ID is valid or invalid. > coresight_trace_id_get_system_id() returns the ID if one can be allocated or -EINVAL if not. Not sure what you are looking at here. Mike > Suzuki
On 06/10/2022 14:54, Mike Leach wrote: > Hi Suzuki, > > On Mon, 3 Oct 2022 at 10:04, Suzuki K Poulose <suzuki.poulose@arm.com> wrote: >> >> On 09/08/2022 23:33, Mike Leach wrote: >>> Updates the STM driver to use the trace ID allocation API. >>> This uses the _system_id calls to allocate an ID on device poll, >>> and release on device remove. >>> >>> The sysfs access to the STMTRACEIDR register has been changed from RW >>> to RO. Having this value as writable is not appropriate for the new >>> Trace ID scheme - and had potential to cause errors in the previous >>> scheme if values clashed with other sources. >>> >>> Signed-off-by: Mike Leach <mike.leach@linaro.org> >>> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> >>> @@ -854,7 +830,7 @@ static void stm_init_generic_data(struct stm_drvdata *drvdata, >>> >>> static int stm_probe(struct amba_device *adev, const struct amba_id *id) >>> { >>> - int ret; >>> + int ret, trace_id; >>> void __iomem *base; >>> struct device *dev = &adev->dev; >>> struct coresight_platform_data *pdata = NULL; >>> @@ -938,12 +914,22 @@ static int stm_probe(struct amba_device *adev, const struct amba_id *id) >>> goto stm_unregister; >>> } >>> >>> + trace_id = coresight_trace_id_get_system_id(); >>> + if (trace_id < 0) { >> >> The above API returns "INVALID_ID" and not a negative error status. >> I think it is better to fix the API to return: >> >> ret < 0 - If there is any error >> - Otherwise a positive integer >> And the users should be kept unaware of which ID is valid or invalid. >> > > coresight_trace_id_get_system_id() returns the ID if one can be > allocated or -EINVAL if not. > > Not sure what you are looking at here. Sorry, indeed I was mistaken there. It is the get_cpu_id() which returns the INVALID_ID on failure. Please could we make that consistent with this scheme ? i.e, < 0 on error. Also, please could we add a comment above the exported functions on their entry/exit criteria ? It is not clearly evident, unless we follow the code and figure out. Cheers Suzuki
Hi suzuki, On Fri, 7 Oct 2022 at 18:53, Suzuki K Poulose <suzuki.poulose@arm.com> wrote: > > On 06/10/2022 14:54, Mike Leach wrote: > > Hi Suzuki, > > > > On Mon, 3 Oct 2022 at 10:04, Suzuki K Poulose <suzuki.poulose@arm.com> wrote: > >> > >> On 09/08/2022 23:33, Mike Leach wrote: > >>> Updates the STM driver to use the trace ID allocation API. > >>> This uses the _system_id calls to allocate an ID on device poll, > >>> and release on device remove. > >>> > >>> The sysfs access to the STMTRACEIDR register has been changed from RW > >>> to RO. Having this value as writable is not appropriate for the new > >>> Trace ID scheme - and had potential to cause errors in the previous > >>> scheme if values clashed with other sources. > >>> > >>> Signed-off-by: Mike Leach <mike.leach@linaro.org> > >>> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> > > >>> @@ -854,7 +830,7 @@ static void stm_init_generic_data(struct stm_drvdata *drvdata, > >>> > >>> static int stm_probe(struct amba_device *adev, const struct amba_id *id) > >>> { > >>> - int ret; > >>> + int ret, trace_id; > >>> void __iomem *base; > >>> struct device *dev = &adev->dev; > >>> struct coresight_platform_data *pdata = NULL; > >>> @@ -938,12 +914,22 @@ static int stm_probe(struct amba_device *adev, const struct amba_id *id) > >>> goto stm_unregister; > >>> } > >>> > >>> + trace_id = coresight_trace_id_get_system_id(); > >>> + if (trace_id < 0) { > >> > >> The above API returns "INVALID_ID" and not a negative error status. > >> I think it is better to fix the API to return: > >> > >> ret < 0 - If there is any error > >> - Otherwise a positive integer > >> And the users should be kept unaware of which ID is valid or invalid. > >> > > > > coresight_trace_id_get_system_id() returns the ID if one can be > > allocated or -EINVAL if not. > > > > Not sure what you are looking at here. > > Sorry, indeed I was mistaken there. It is the get_cpu_id() which > returns the INVALID_ID on failure. Please could we make that > consistent with this scheme ? i.e, < 0 on error. > That also returns -EINVAL, as both call the same underlying allocator. However happy to add on the comments for the exported functions Regards Mike > Also, please could we add a comment above the exported functions > on their entry/exit criteria ? It is not clearly evident, unless > we follow the code and figure out. > > Cheers > Suzuki >
On 11/10/2022 12:10, Mike Leach wrote: > Hi suzuki, > > On Fri, 7 Oct 2022 at 18:53, Suzuki K Poulose <suzuki.poulose@arm.com> wrote: >> >> On 06/10/2022 14:54, Mike Leach wrote: >>> Hi Suzuki, >>> >>> On Mon, 3 Oct 2022 at 10:04, Suzuki K Poulose <suzuki.poulose@arm.com> wrote: >>>> >>>> On 09/08/2022 23:33, Mike Leach wrote: >>>>> Updates the STM driver to use the trace ID allocation API. >>>>> This uses the _system_id calls to allocate an ID on device poll, >>>>> and release on device remove. >>>>> >>>>> The sysfs access to the STMTRACEIDR register has been changed from RW >>>>> to RO. Having this value as writable is not appropriate for the new >>>>> Trace ID scheme - and had potential to cause errors in the previous >>>>> scheme if values clashed with other sources. >>>>> >>>>> Signed-off-by: Mike Leach <mike.leach@linaro.org> >>>>> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> >> >>>>> @@ -854,7 +830,7 @@ static void stm_init_generic_data(struct stm_drvdata *drvdata, >>>>> >>>>> static int stm_probe(struct amba_device *adev, const struct amba_id *id) >>>>> { >>>>> - int ret; >>>>> + int ret, trace_id; >>>>> void __iomem *base; >>>>> struct device *dev = &adev->dev; >>>>> struct coresight_platform_data *pdata = NULL; >>>>> @@ -938,12 +914,22 @@ static int stm_probe(struct amba_device *adev, const struct amba_id *id) >>>>> goto stm_unregister; >>>>> } >>>>> >>>>> + trace_id = coresight_trace_id_get_system_id(); >>>>> + if (trace_id < 0) { >>>> >>>> The above API returns "INVALID_ID" and not a negative error status. >>>> I think it is better to fix the API to return: >>>> >>>> ret < 0 - If there is any error >>>> - Otherwise a positive integer >>>> And the users should be kept unaware of which ID is valid or invalid. >>>> >>> >>> coresight_trace_id_get_system_id() returns the ID if one can be >>> allocated or -EINVAL if not. >>> >>> Not sure what you are looking at here. >> >> Sorry, indeed I was mistaken there. It is the get_cpu_id() which >> returns the INVALID_ID on failure. Please could we make that >> consistent with this scheme ? i.e, < 0 on error. >> > > That also returns -EINVAL, as both call the same underlying allocator. You're right, the check in coresight_trace_id_map_get_cpu_id(), confused me. > However happy to add on the comments for the exported functions Yes, please. Thanks Mike Suzuki
diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c index bb14a3a8a921..9ef3e923a930 100644 --- a/drivers/hwtracing/coresight/coresight-stm.c +++ b/drivers/hwtracing/coresight/coresight-stm.c @@ -31,6 +31,7 @@ #include <linux/stm.h> #include "coresight-priv.h" +#include "coresight-trace-id.h" #define STMDMASTARTR 0xc04 #define STMDMASTOPR 0xc08 @@ -615,24 +616,7 @@ static ssize_t traceid_show(struct device *dev, val = drvdata->traceid; return sprintf(buf, "%#lx\n", val); } - -static ssize_t traceid_store(struct device *dev, - struct device_attribute *attr, - const char *buf, size_t size) -{ - int ret; - unsigned long val; - struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent); - - ret = kstrtoul(buf, 16, &val); - if (ret) - return ret; - - /* traceid field is 7bit wide on STM32 */ - drvdata->traceid = val & 0x7f; - return size; -} -static DEVICE_ATTR_RW(traceid); +static DEVICE_ATTR_RO(traceid); #define coresight_stm_reg(name, offset) \ coresight_simple_reg32(struct stm_drvdata, name, offset) @@ -819,14 +803,6 @@ static void stm_init_default_data(struct stm_drvdata *drvdata) */ drvdata->stmsper = ~0x0; - /* - * The trace ID value for *ETM* tracers start at CPU_ID * 2 + 0x10 and - * anything equal to or higher than 0x70 is reserved. Since 0x00 is - * also reserved the STM trace ID needs to be higher than 0x00 and - * lowner than 0x10. - */ - drvdata->traceid = 0x1; - /* Set invariant transaction timing on all channels */ bitmap_clear(drvdata->chs.guaranteed, 0, drvdata->numsp); } @@ -854,7 +830,7 @@ static void stm_init_generic_data(struct stm_drvdata *drvdata, static int stm_probe(struct amba_device *adev, const struct amba_id *id) { - int ret; + int ret, trace_id; void __iomem *base; struct device *dev = &adev->dev; struct coresight_platform_data *pdata = NULL; @@ -938,12 +914,22 @@ static int stm_probe(struct amba_device *adev, const struct amba_id *id) goto stm_unregister; } + trace_id = coresight_trace_id_get_system_id(); + if (trace_id < 0) { + ret = trace_id; + goto cs_unregister; + } + drvdata->traceid = (u8)trace_id; + pm_runtime_put(&adev->dev); dev_info(&drvdata->csdev->dev, "%s initialized\n", (char *)coresight_get_uci_data(id)); return 0; +cs_unregister: + coresight_unregister(drvdata->csdev); + stm_unregister: stm_unregister_device(&drvdata->stm); return ret; @@ -953,6 +939,7 @@ static void stm_remove(struct amba_device *adev) { struct stm_drvdata *drvdata = dev_get_drvdata(&adev->dev); + coresight_trace_id_put_system_id(drvdata->traceid); coresight_unregister(drvdata->csdev); stm_unregister_device(&drvdata->stm);