Re: [PATCH v5 07/14] coresight: cti: Add device tree support for custom CTI.

From: Mike Leach <mike.leach@linaro.org>
To: Suzuki Kuruppassery Poulose <suzuki.poulose@arm.com>
Cc: Coresight ML <coresight@lists.linaro.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	devicetree@vger.kernel.org,
	"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
	Mathieu Poirier <mathieu.poirier@linaro.org>
Subject: Re: [PATCH v5 07/14] coresight: cti: Add device tree support for custom CTI.
Date: Tue, 3 Dec 2019 14:05:52 +0000	[thread overview]
Message-ID: <CAJ9a7Vgce=i9JEV2JRThj74wKYRNcR24RBu5qKqnspcVcqhwiQ@mail.gmail.com> (raw)
In-Reply-To: <efac03bc-4a38-8f5c-46d5-9ffc58b2d2bb@arm.com>

Hi Suzuki,

On Fri, 29 Nov 2019 at 14:18, Suzuki Kuruppassery Poulose
<suzuki.poulose@arm.com> wrote:
>
> On 19/11/2019 23:19, Mike Leach wrote:
> > Adds support for CTIs whose connections are implementation defined at
> > hardware design time, and not constrained by v8 architecture.
> >
> > These CTIs have no standard connection setup, all the settings have to
> > be defined in the device tree files. The patch creates a set of connections
> > and trigger signals based on the information provided.
> >
> > Signed-off-by: Mike Leach <mike.leach@linaro.org>
> > ---
> >   .../coresight/coresight-cti-platform.c        | 250 +++++++++++++++++-
> >   .../hwtracing/coresight/coresight-cti-sysfs.c |  11 +
> >   2 files changed, 257 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-cti-platform.c b/drivers/hwtracing/coresight/coresight-cti-platform.c
> > index 790dd30b85f5..9c1ff432b487 100644
> > --- a/drivers/hwtracing/coresight/coresight-cti-platform.c
> > +++ b/drivers/hwtracing/coresight/coresight-cti-platform.c
> > @@ -13,9 +13,19 @@
> >   #define NR_V8PE_OUT_SIGS    3
> >   #define NR_V8ETM_INOUT_SIGS 4
> >
> > +/* CTI device tree trigger connection node keyword */
> > +#define CTI_DT_CONNS         "trig-conns"
> > +
> >   /* CTI device tree connection property keywords */
> >   #define CTI_DT_V8ARCH               "arm,cti-v8-arch"
> >   #define CTI_DT_CSDEV_ASSOC  "arm,cs-dev-assoc"
> > +#define CTI_DT_TRIGIN_SIGS   "arm,trig-in-sigs"
> > +#define CTI_DT_TRIGOUT_SIGS  "arm,trig-out-sigs"
> > +#define CTI_DT_TRIGIN_TYPES  "arm,trig-in-types"
> > +#define CTI_DT_TRIGOUT_TYPES "arm,trig-out-types"
> > +#define CTI_DT_FILTER_OUT_SIGS       "arm,trig-filters"
> > +#define CTI_DT_CONN_NAME     "arm,trig-conn-name"
> > +#define CTI_DT_CTM_ID                "arm,cti-ctm-id"
> >
> >   /*
> >    * Find a registered coresight device from a device fwnode.
> > @@ -68,6 +78,12 @@ static const char *of_cti_get_node_name(const struct device_node *node)
> >               return node->full_name;
> >       return "unknown";
> >   }
> > +
> > +static bool of_cti_node_name_eq(const struct device_node *node,
> > +                             const char *name)
> > +{
> > +     return of_node_name_eq(node, name);
> > +}
> >   #else
> >   static int of_cti_get_cpu_at_node(const struct device_node *node)
> >   {
> > @@ -78,6 +94,12 @@ static const char *of_cti_get_node_name(const struct device_node *node)
> >   {
> >       return "unknown";
> >   }
> > +
> > +static bool of_cti_node_name_eq(const struct device_node *node,
> > +                             const char *name)
> > +{
> > +     return false;
> > +}
> >   #endif
>
> nit: You don't need this wrapper of_node_name_eq() is already defined to
> return false for !CONFIG_OF.
>
>

OK.

> >
> >   static int cti_plat_get_cpu_at_node(struct fwnode_handle *fwnode)
> > @@ -94,6 +116,14 @@ static const char *cti_plat_get_node_name(struct fwnode_handle *fwnode)
> >       return "unknown";
> >   }
> >
> > +static bool cti_plat_node_name_eq(struct fwnode_handle *fwnode,
> > +                               const char *name)
> > +{
> > +     if (is_of_node(fwnode))
> > +             return of_cti_node_name_eq(to_of_node(fwnode), name);
>
> As mentioned above you could simply use of_node_name_eq() here.
>
> > +     return false;
> > +}
> > +
> >   static int cti_plat_create_v8_etm_connection(struct device *dev,
> >                                            struct cti_drvdata *drvdata)
> >   {
> > @@ -205,6 +235,214 @@ static int cti_plat_create_v8_connections(struct device *dev,
> >       return ret;
> >   }
> >
> > +static int cti_plat_count_sig_elements(const struct fwnode_handle *fwnode,
> > +                                    const char *name)
> > +{
> > +     int nr_elem = fwnode_property_count_u32(fwnode, name);
> > +
> > +     return (nr_elem < 0 ? 0 : nr_elem);
> > +}
> > +
> > +static int cti_plat_read_trig_group(struct cti_trig_grp *tgrp,
> > +                                 const struct fwnode_handle *fwnode,
> > +                                 const char *grp_name)
> > +{
> > +     int idx, err = 0;
> > +     u32 *values;
> > +
> > +     if (!tgrp->nr_sigs)
> > +             return 0;
> > +
> > +     values = kcalloc(tgrp->nr_sigs, sizeof(u32), GFP_KERNEL);
> > +     if (!values)
> > +             return -ENOMEM;
> > +
> > +     err = fwnode_property_read_u32_array(fwnode, grp_name,
> > +                                          values, tgrp->nr_sigs);
> > +
> > +     if (!err) {
> > +             /* set the signal usage mask */
> > +             for (idx = 0; idx < tgrp->nr_sigs; idx++)
> > +                     tgrp->used_mask |= BIT(values[idx]);
> > +     }
> > +
> > +     kfree(values);
> > +     return err;
> > +}
> > +
> > +static int cti_plat_read_trig_types(struct cti_trig_grp *tgrp,
> > +                                 const struct fwnode_handle *fwnode,
> > +                                 const char *type_name)
> > +{
> > +     int items, used = 0, err = 0, nr_sigs;
> > +     u32 *values = NULL, i;
> > +
> > +     /* allocate an array according to number of signals in connection */
> > +     nr_sigs = tgrp->nr_sigs;
> > +     if (!nr_sigs)
> > +             return 0;
> > +
> > +     /* see if any types have been included in the device description */
> > +     items = cti_plat_count_sig_elements(fwnode, type_name);
> > +     if (items > nr_sigs)
> > +             return -EINVAL;
> > +
> > +     /* need an array to store the values iff there are any */
> > +     if (items) {
> > +             values = kcalloc(items, sizeof(u32), GFP_KERNEL);
> > +             if (!values)
> > +                     return -ENOMEM;
> > +
> > +             err = fwnode_property_read_u32_array(fwnode, type_name,
> > +                                                  values, items);
> > +             if (err)
> > +                     goto read_trig_types_out;
> > +     }
> > +
> > +     /*
> > +      * Match type id to signal index, 1st type to 1st index etc.
> > +      * If fewer types than signals default remainder to GEN_IO.
> > +      */
> > +     for (i = 0; i < nr_sigs; i++) {
> > +             if (used < items) {
> > +                     tgrp->sig_types[i] =
> > +                             values[i] < CTI_TRIG_MAX ? values[i] : GEN_IO;
> > +                     used++;
>
> Do we really need "used" here ? Couldn't this be :
>
No we don't - I'll fix it.

>                 if (i < items) {
>
>                 }
>
> > +             } else {
>
>    +                    /* Mark the undefined connections as GEN_IO */ ?
>
> > +                     tgrp->sig_types[i] = GEN_IO;
> > +             }
> > +     }
>
> ...
>
> > +
> > +     /* read the connection name if set - may be overridden by later */
> > +     fwnode_property_read_string(fwnode, CTI_DT_CONN_NAME, &assoc_name);
> > +
> > +     /* associated cpu ? */
> > +     cpuid = cti_plat_get_cpu_at_node(fwnode);
> > +     if (cpuid >= 0) {
> > +             drvdata->ctidev.cpu = cpuid;
> > +             scnprintf(cpu_name_str, sizeof(cpu_name_str), "cpu%d", cpuid);
> > +             assoc_name = cpu_name_str;
> > +     } else {
> > +             /* associated device ? */
> > +             cs_fwnode = fwnode_find_reference(fwnode,
> > +                                               CTI_DT_CSDEV_ASSOC, 0);
>
> > +             if (!IS_ERR_OR_NULL(cs_fwnode)) {
>
> --- Cut - here --
> > +                     csdev = cti_get_assoc_csdev_by_fwnode(cs_fwnode);
> > +                     if (csdev) /* use device name if csdev found */
> > +                             assoc_name = dev_name(&csdev->dev);
> > +                     else  /* otherwise node name for later association */
> > +                             assoc_name = cti_plat_get_node_name(cs_fwnode);
>
> --- end - here --
>
> I believe we do this for arm_v8 architected connections too. May be make
> this a helper ?
>
OK

> > +                     fwnode_handle_put(cs_fwnode);
> > +             }
> > +     }
> > +     /* set up a connection */
> > +     err = cti_add_connection_entry(dev, drvdata, tc, csdev, assoc_name);
> > +
> > +create_con_err:
> > +     return err;
> > +}
> > +
> > +static int cti_plat_create_impdef_connections(struct device *dev,
> > +                                           struct cti_drvdata *drvdata)
> > +{
> > +     int rc = 0;
> > +     struct fwnode_handle *fwnode = dev_fwnode(dev);
> > +     struct fwnode_handle *child = NULL;
> > +
> > +     if (IS_ERR_OR_NULL(fwnode))
> > +             return -EINVAL;
> > +
> > +     fwnode_for_each_child_node(fwnode, child) {
> > +             if (cti_plat_node_name_eq(child, CTI_DT_CONNS))
> > +                     rc = cti_plat_create_connection(dev, drvdata, child);
> > +             if (rc != 0)
> > +                     break;
>
> minor nit: To make it more obvious :
>
>                 if (cti_plat_node_name_eq(child, CTI_DT_CONNS)) {
>                         rc = cti_plat_create_connection(dev, drvdata,
>                                                         child);
>                         if (rc)
>                                 break;
>                 }
>
> Suzuki

Thanks

Mike

--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK