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Message-ID: <20200729195617.GB3073178@xps15>
Date: Wed, 29 Jul 2020 13:56:17 -0600
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Suzuki K Poulose <suzuki.poulose@....com>
Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
mike.leach@...aro.org, coresight@...ts.linaro.org
Subject: Re: [RFC PATCH 02/14] coresight: Introduce device access abstraction
On Wed, Jul 22, 2020 at 06:20:28PM +0100, Suzuki K Poulose wrote:
> We are about to introduce support for sysreg access to ETMv4.4+
> component. Since there are generic routines that access the
> registers (e.g, CS_LOCK/UNLOCK , claim/disclaim operations, timeout)
> and in order to preserve the logic of these operations at a single place
> we introduce an abstraction layer for the accesses to a given device.
> This will also be helpful in consolidating the sysfs.attribute helpers,
> that we define per driver.
Please drop the last sentence, it doesn't add to the current patch.
>
> Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
> Cc: Mike Leach <mike.leach@...aro.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
> ---
> drivers/hwtracing/coresight/coresight-catu.c | 1 +
> drivers/hwtracing/coresight/coresight-cti.c | 1 +
> drivers/hwtracing/coresight/coresight-etb10.c | 1 +
> drivers/hwtracing/coresight/coresight-etm3x.c | 1 +
> drivers/hwtracing/coresight/coresight-etm4x.c | 1 +
> .../hwtracing/coresight/coresight-funnel.c | 1 +
> .../coresight/coresight-replicator.c | 1 +
> drivers/hwtracing/coresight/coresight-stm.c | 1 +
> drivers/hwtracing/coresight/coresight-tmc.c | 1 +
> drivers/hwtracing/coresight/coresight-tpiu.c | 1 +
> drivers/hwtracing/coresight/coresight.c | 49 ++++++
> include/linux/coresight.h | 156 ++++++++++++++++++
> 12 files changed, 215 insertions(+)
>
> diff --git a/drivers/hwtracing/coresight/coresight-catu.c b/drivers/hwtracing/coresight/coresight-catu.c
> index 1801804a7762..6299ff7b8a14 100644
> --- a/drivers/hwtracing/coresight/coresight-catu.c
> +++ b/drivers/hwtracing/coresight/coresight-catu.c
> @@ -551,6 +551,7 @@ static int catu_probe(struct amba_device *adev, const struct amba_id *id)
> dev->platform_data = pdata;
>
> drvdata->base = base;
> + catu_desc.access.base = base;
> catu_desc.pdata = pdata;
> catu_desc.dev = dev;
> catu_desc.groups = catu_groups;
> diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
> index 3ccc703dc940..c810ea3ba155 100644
> --- a/drivers/hwtracing/coresight/coresight-cti.c
> +++ b/drivers/hwtracing/coresight/coresight-cti.c
> @@ -865,6 +865,7 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
> return PTR_ERR(base);
>
> drvdata->base = base;
> + cti_desc.access.base = base;
>
> dev_set_drvdata(dev, drvdata);
>
> diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
> index 03e3f2590191..0f2735e15119 100644
> --- a/drivers/hwtracing/coresight/coresight-etb10.c
> +++ b/drivers/hwtracing/coresight/coresight-etb10.c
> @@ -755,6 +755,7 @@ static int etb_probe(struct amba_device *adev, const struct amba_id *id)
> return PTR_ERR(base);
>
> drvdata->base = base;
> + desc.access.base = base;
>
> spin_lock_init(&drvdata->spinlock);
>
> diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
> index bf22dcfd3327..7ddcb7fcb2d6 100644
> --- a/drivers/hwtracing/coresight/coresight-etm3x.c
> +++ b/drivers/hwtracing/coresight/coresight-etm3x.c
> @@ -805,6 +805,7 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id)
> return PTR_ERR(base);
>
> drvdata->base = base;
> + desc.access.base = base;
>
> spin_lock_init(&drvdata->spinlock);
>
> diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
> index cb83fb77ded6..7bb74c659c4f 100644
> --- a/drivers/hwtracing/coresight/coresight-etm4x.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.c
> @@ -1501,6 +1501,7 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id)
> return PTR_ERR(base);
>
> drvdata->base = base;
> + desc.access.base = base;
>
> spin_lock_init(&drvdata->spinlock);
>
> diff --git a/drivers/hwtracing/coresight/coresight-funnel.c b/drivers/hwtracing/coresight/coresight-funnel.c
> index 900690a9f7f0..67fc3e3b77d8 100644
> --- a/drivers/hwtracing/coresight/coresight-funnel.c
> +++ b/drivers/hwtracing/coresight/coresight-funnel.c
> @@ -242,6 +242,7 @@ static int funnel_probe(struct device *dev, struct resource *res)
> }
> drvdata->base = base;
> desc.groups = coresight_funnel_groups;
> + desc.access.base = base;
> }
>
> dev_set_drvdata(dev, drvdata);
> diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
> index 78acf29c49ca..65704ada20a5 100644
> --- a/drivers/hwtracing/coresight/coresight-replicator.c
> +++ b/drivers/hwtracing/coresight/coresight-replicator.c
> @@ -254,6 +254,7 @@ static int replicator_probe(struct device *dev, struct resource *res)
> }
> drvdata->base = base;
> desc.groups = replicator_groups;
> + desc.access.base = base;
> }
>
> if (fwnode_property_present(dev_fwnode(dev),
> diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
> index 673d2f56ed1e..c8509cc78512 100644
> --- a/drivers/hwtracing/coresight/coresight-stm.c
> +++ b/drivers/hwtracing/coresight/coresight-stm.c
> @@ -881,6 +881,7 @@ static int stm_probe(struct amba_device *adev, const struct amba_id *id)
> if (IS_ERR(base))
> return PTR_ERR(base);
> drvdata->base = base;
> + desc.access.base = base;
>
> ret = stm_get_stimulus_area(dev, &ch_res);
> if (ret)
> diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
> index 7040d583bed9..b49795ad6861 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc.c
> @@ -458,6 +458,7 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
> }
>
> drvdata->base = base;
> + desc.access.base = base;
>
> spin_lock_init(&drvdata->spinlock);
>
> diff --git a/drivers/hwtracing/coresight/coresight-tpiu.c b/drivers/hwtracing/coresight/coresight-tpiu.c
> index f8583e4032a6..7ef7649f48ad 100644
> --- a/drivers/hwtracing/coresight/coresight-tpiu.c
> +++ b/drivers/hwtracing/coresight/coresight-tpiu.c
> @@ -149,6 +149,7 @@ static int tpiu_probe(struct amba_device *adev, const struct amba_id *id)
> return PTR_ERR(base);
>
> drvdata->base = base;
> + desc.access.base = base;
>
> /* Disable tpiu to support older devices */
> tpiu_disable_hw(drvdata);
> diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
> index e9c90f2de34a..38e9c03ab754 100644
> --- a/drivers/hwtracing/coresight/coresight.c
> +++ b/drivers/hwtracing/coresight/coresight.c
> @@ -1387,6 +1387,54 @@ static int __init coresight_init(void)
> }
> postcore_initcall(coresight_init);
>
> +u32 coresight_relaxed_read32(struct coresight_device *csdev, u32 offset)
> +{
> + return csdev_access_relaxed_read32(&csdev->access, offset);
> +}
> +
> +u32 coresight_read32(struct coresight_device *csdev, u32 offset)
> +{
> + return csdev_access_read32(&csdev->access, offset);
> +}
> +
> +void coresight_relaxed_write32(struct coresight_device *csdev,
> + u32 val,
> + u32 offset)
> +{
> +
Extra line
> + csdev_access_relaxed_write32(&csdev->access, val, offset);
> +}
> +
> +
> +void coresight_write32(struct coresight_device *csdev, u32 val, u32 offset)
> +{
> + csdev_access_write32(&csdev->access, val, offset);
> +}
> +
> +u64 coresight_relaxed_read64(struct coresight_device *csdev, u32 offset)
> +{
> + return csdev_access_relaxed_read64(&csdev->access, offset);
> +}
> +
> +u64 coresight_read64(struct coresight_device *csdev, u32 offset)
> +{
> + return csdev_access_read64(&csdev->access, offset);
> +}
> +
> +void coresight_relaxed_write64(struct coresight_device *csdev,
> + u64 val,
> + u32 offset)
> +{
> +
Extra line
> + csdev_access_relaxed_write64(&csdev->access, val, offset);
> +}
> +
> +
> +void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset)
> +{
> + csdev_access_write64(&csdev->access, val, offset);
> +}
> +
> /*
> * coresight_release_platform_data: Release references to the devices connected
> * to the output port of this device.
> @@ -1451,6 +1499,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
> csdev->type = desc->type;
> csdev->subtype = desc->subtype;
> csdev->ops = desc->ops;
> + csdev->access = desc->access;
> csdev->orphan = false;
>
> csdev->dev.type = &coresight_dev_type[desc->type];
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index 58fffdecdbfd..81ac708689f8 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -7,6 +7,7 @@
> #define _LINUX_CORESIGHT_H
>
> #include <linux/device.h>
> +#include <linux/io.h>
> #include <linux/perf_event.h>
> #include <linux/sched.h>
>
> @@ -114,6 +115,32 @@ struct coresight_platform_data {
> struct coresight_connection *conns;
> };
>
> +/**
> + * struct csdev_access - Abstraction of a CoreSight device access.
> + *
> + * @no_iomem : True if the device doesn't have iomem access.
> + * @base : When no_iomem == false, base address of the component
> + * @read : Read from the given "offset" of the given instance.
> + * @write : Write "val" to the given "offset".
> + */
> +struct csdev_access {
> + bool no_iomem;
I find the no_iomen to be difficult to understand, especially when prefixed with
'!'. Using "has_iomem" would be a lot more intuitive and would avoid extra
mental gymnastics.
> + union {
> + void __iomem *base;
> + struct {
> + u64 (*read)(struct csdev_access *csa,
> + u32 offset,
> + bool relaxed,
> + bool _64bit);
> + void (*write)(struct csdev_access *csa,
> + u64 val,
> + u32 offset,
> + bool relaxed,
> + bool _64bit);
> + };
> + };
> +};
> +
> /**
> * struct coresight_desc - description of a component required from drivers
> * @type: as defined by @coresight_dev_type.
> @@ -134,6 +161,7 @@ struct coresight_desc {
> struct device *dev;
> const struct attribute_group **groups;
> const char *name;
> + struct csdev_access access;
No documentation
> };
>
> /**
> @@ -186,6 +214,7 @@ struct coresight_sysfs_link {
> * @def_sink: cached reference to default sink found for this device.
> * @ect_dev: Associated cross trigger device. Not part of the trace data
> * path or connections.
> + * @csa: Device i/o access abstraction for this device.
> * @nr_links: number of sysfs links created to other components from this
> * device. These will appear in the "connections" group.
> * @has_conns_grp: Have added a "connections" group for sysfs links.
> @@ -205,6 +234,7 @@ struct coresight_device {
> struct coresight_device *def_sink;
> /* cross trigger handling */
> struct coresight_device *ect_dev;
> + struct csdev_access access;
Documentation and field don't match.
> /* sysfs links between components */
> int nr_links;
> bool has_conns_grp;
> @@ -324,6 +354,79 @@ struct coresight_ops {
> const struct coresight_ops_ect *ect_ops;
> };
>
> +static inline u32 csdev_access_relaxed_read32(struct csdev_access *csa,
> + u32 offset)
> +{
> + if (likely(!csa->no_iomem))
> + return readl_relaxed(csa->base + offset);
> + return csa->read(csa, offset, true, false);
> +}
> +
> +static inline u64 csdev_access_relaxed_read64(struct csdev_access *csa,
> + u32 offset)
> +{
> + if (likely(!csa->no_iomem))
> + return readq_relaxed(csa->base + offset);
> + return csa->read(csa, offset, true, true);
> +}
> +
> +static inline u32 csdev_access_read32(struct csdev_access *csa, u32 offset)
> +{
> + if (likely(!csa->no_iomem))
> + return readl(csa->base + offset);
> + return csa->read(csa, offset, false, false);
> +}
> +
> +static inline u64 csdev_access_read64(struct csdev_access *csa, u32 offset)
> +{
> + if (likely(!csa->no_iomem))
> + return readq(csa->base + offset);
> + return csa->read(csa, offset, false, true);
> +}
> +
All of the above don't have a new line after the if() condition while the ones
below do. Please pick a heurisitic and stick with it throughout.
> +static inline void csdev_access_relaxed_write32(struct csdev_access *csa,
> + u32 val,
> + u32 offset)
> +{
> + if (likely(!csa->no_iomem))
> + return writel_relaxed(val, csa->base + offset);
> +
> + return csa->write(csa, val, offset, true, false);
> +}
> +
> +static inline void csdev_access_relaxed_write64(struct csdev_access *csa,
> + u64 val,
> + u32 offset)
> +{
> + if (likely(!csa->no_iomem))
> + return writeq_relaxed(val, csa->base + offset);
> +
> + return csa->write(csa, val, offset, true, true);
> +}
> +
> +static inline void csdev_access_write32(struct csdev_access *csa, u32 val, u32 offset)
> +{
> + if (likely(!csa->no_iomem))
> + return writel(val, csa->base + offset);
> +
> + return csa->write(csa, val, offset, false, false);
> +}
> +
> +static inline void csdev_access_write64(struct csdev_access *csa, u64 val, u32 offset)
> +{
> + if (likely(!csa->no_iomem))
> + return writeq(val, csa->base + offset);
> +
> + return csa->write(csa, val, offset, false, true);
> +}
> +
> +
> +u64 coresight_relaxed_read64(struct coresight_device *csdev, u32 offset);
> +u64 coresight_read64(struct coresight_device *csdev, u32 offset);
> +void coresight_relaxed_write64(struct coresight_device *csdev,
> + u64 val, u32 offset);
> +void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset);
> +
> #ifdef CONFIG_CORESIGHT
> extern struct coresight_device *
> coresight_register(struct coresight_desc *desc);
> @@ -342,6 +445,14 @@ extern char *coresight_alloc_device_name(struct coresight_dev_list *devs,
> struct device *dev);
>
> extern bool coresight_loses_context_with_cpu(struct device *dev);
> +
> +u32 coresight_relaxed_read32(struct coresight_device *csdev, u32 offset);
> +u32 coresight_read32(struct coresight_device *csdev, u32 offset);
> +void coresight_write32(struct coresight_device *csdev, u32 val, u32 offset);
> +void coresight_relaxed_write32(struct coresight_device *csdev,
> + u32 val,
> + u32 offset);
> +
Why are the 64 bit version outside of the #ifdef and the 32 bit within?
> #else
> static inline struct coresight_device *
> coresight_register(struct coresight_desc *desc) { return NULL; }
> @@ -368,6 +479,51 @@ static inline bool coresight_loses_context_with_cpu(struct device *dev)
> {
> return false;
> }
> +
> +static inline u32 coresight_relaxed_read32(struct coresight_device *csdev, u32 offset)
> +{
> + WARN_ON_ONCE(1);
> + return 0;
> +}
> +
> +static inline u32 coresight_read32(struct coresight_device *csdev, u32 offset)
> +{
> + WARN_ON_ONCE(1);
> + return 0;
> +}
> +
> +static void coresight_write32(struct coresight_device *csdev, u32 val, u32 offset)
> +{
> +}
> +
> +static void coresight_relaxed_write32(struct coresight_device *csdev,
> + u32 val, u32 offset);
> +{
> +}
> +
> +static inline u64 coresight_relaxed_read64(struct coresight_device *csdev,
> + u32 offset)
> +{
> + WARN_ON_ONCE(1);
> + return 0;
> +}
> +
> +static inline u64 coresight_read64(struct coresight_device *csdev, u32 offset)
> +{
> + WARN_ON_ONCE(1);
Not sure about the motivation behind using WARN_ON_ONCE(), and only in the read
functions. I would simply return 0 here. After all if CONFIG_CORESIGHT is not
defined they won't make it very far.
> + return 0;
> +}
> +
> +static inline void coresight_relaxed_write64(struct coresight_device *csdev,
> + u64 val,
> + u32 offset)
> +{
> +}
> +
> +static inline void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset)
> +{
> +}
> +
> #endif
I will likely come back to this patch once I have reviewed the rest of the set.
>
> extern int coresight_get_cpu(struct device *dev);
> --
> 2.24.1
>
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