arm_mpam: Add quirk framework

The MPAM specification includes the MPAMF_IIDR, which serves to uniquely
identify the MSC implementation through a combination of implementer
details, product ID, variant, and revision. Certain hardware issues/errata
can be resolved using software workarounds.

Introduce a quirk framework to allow workarounds to be enabled based on the
MPAMF_IIDR value.

Tested-by: Gavin Shan <gshan@redhat.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Zeng Heng <zengheng4@huawei.com>
Tested-by: Punit Agrawal <punit.agrawal@oss.qualcomm.com>
Tested-by: Jesse Chick <jessechick@os.amperecomputing.com>
Reviewed-by: Zeng Heng <zengheng4@huawei.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Co-developed-by: Ben Horgan <ben.horgan@arm.com>
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Co-developed-by: James Morse <james.morse@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>

diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index 37b31a1cf376ce9d50925b7bca96f363e4f85064..e66631f3f7321cb02935bc48a9770654019e4238 100644 (file)
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -630,6 +630,30 @@ static struct mpam_msc_ris *mpam_get_or_create_ris(struct mpam_msc *msc,
        return ERR_PTR(-ENOENT);
 }
 
+static const struct mpam_quirk mpam_quirks[] = {
+       { NULL } /* Sentinel */
+};
+
+static void mpam_enable_quirks(struct mpam_msc *msc)
+{
+       const struct mpam_quirk *quirk;
+
+       for (quirk = &mpam_quirks[0]; quirk->iidr_mask; quirk++) {
+               int err = 0;
+
+               if (quirk->iidr != (msc->iidr & quirk->iidr_mask))
+                       continue;
+
+               if (quirk->init)
+                       err = quirk->init(msc, quirk);
+
+               if (err)
+                       continue;
+
+               mpam_set_quirk(quirk->workaround, msc);
+       }
+}
+
 /*
  * IHI009A.a has this nugget: "If a monitor does not support automatic behaviour
  * of NRDY, software can use this bit for any purpose" - so hardware might not
@@ -864,8 +888,11 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc)
        /* Grab an IDR value to find out how many RIS there are */
        mutex_lock(&msc->part_sel_lock);
        idr = mpam_msc_read_idr(msc);
+       msc->iidr = mpam_read_partsel_reg(msc, IIDR);
        mutex_unlock(&msc->part_sel_lock);
 
+       mpam_enable_quirks(msc);
+
        msc->ris_max = FIELD_GET(MPAMF_IDR_RIS_MAX, idr);
 
        /* Use these values so partid/pmg always starts with a valid value */
@@ -1972,6 +1999,7 @@ static bool mpam_has_cmax_wd_feature(struct mpam_props *props)
  * resulting safe value must be compatible with both. When merging values in
  * the tree, all the aliasing resources must be handled first.
  * On mismatch, parent is modified.
+ * Quirks on an MSC will apply to all MSC in that class.
  */
 static void __props_mismatch(struct mpam_props *parent,
                             struct mpam_props *child, bool alias)
@@ -2091,6 +2119,7 @@ static void __props_mismatch(struct mpam_props *parent,
  * nobble the class feature, as we can't configure all the resources.
  * e.g. The L3 cache is composed of two resources with 13 and 17 portion
  * bitmaps respectively.
+ * Quirks on an MSC will apply to all MSC in that class.
  */
 static void
 __class_props_mismatch(struct mpam_class *class, struct mpam_vmsc *vmsc)
@@ -2104,6 +2133,9 @@ __class_props_mismatch(struct mpam_class *class, struct mpam_vmsc *vmsc)
        dev_dbg(dev, "Merging features for class:0x%lx &= vmsc:0x%lx\n",
                (long)cprops->features, (long)vprops->features);
 
+       /* Merge quirks */
+       class->quirks |= vmsc->msc->quirks;
+
        /* Take the safe value for any common features */
        __props_mismatch(cprops, vprops, false);
 }

diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
index 68906c6ebfb01053192bc7d92f39f13499644e36..01858365cd9e730031cec37e5fab2affe4e83105 100644 (file)
--- a/drivers/resctrl/mpam_internal.h
+++ b/drivers/resctrl/mpam_internal.h
@@ -85,6 +85,8 @@ struct mpam_msc {
        u8                      pmg_max;
        unsigned long           ris_idxs;
        u32                     ris_max;
+       u32                     iidr;
+       u16                     quirks;
 
        /*
         * error_irq_lock is taken when registering/unregistering the error
@@ -216,6 +218,28 @@ struct mpam_props {
 #define mpam_set_feature(_feat, x)     __set_bit(_feat, (x)->features)
 #define mpam_clear_feature(_feat, x)   __clear_bit(_feat, (x)->features)
 
+/* Workaround bits for msc->quirks */
+enum mpam_device_quirks {
+       MPAM_QUIRK_LAST
+};
+
+#define mpam_has_quirk(_quirk, x)      ((1 << (_quirk) & (x)->quirks))
+#define mpam_set_quirk(_quirk, x)      ((x)->quirks |= (1 << (_quirk)))
+
+struct mpam_quirk {
+       int (*init)(struct mpam_msc *msc, const struct mpam_quirk *quirk);
+
+       u32 iidr;
+       u32 iidr_mask;
+
+       enum mpam_device_quirks workaround;
+};
+
+#define MPAM_IIDR_MATCH_ONE    (FIELD_PREP_CONST(MPAMF_IIDR_PRODUCTID,   0xfff) | \
+                                FIELD_PREP_CONST(MPAMF_IIDR_VARIANT,     0xf)   | \
+                                FIELD_PREP_CONST(MPAMF_IIDR_REVISION,    0xf)   | \
+                                FIELD_PREP_CONST(MPAMF_IIDR_IMPLEMENTER, 0xfff))
+
 /* The values for MSMON_CFG_MBWU_FLT.RWBW */
 enum mon_filter_options {
        COUNT_BOTH      = 0,
@@ -259,6 +283,7 @@ struct mpam_class {
 
        struct mpam_props       props;
        u32                     nrdy_usec;
+       u16                     quirks;
        u8                      level;
        enum mpam_class_types   type;