coresight: etm4x: Drop pid argument from etm4_probe()

Coresight device pid can be retrieved from its iomem base address, which is
stored in 'struct etm4x_drvdata'. This drops pid argument from etm4_probe()
and 'struct etm4_init_arg'. Instead etm4_check_arch_features() derives the
coresight device pid with a new helper coresight_get_pid(), right before it
is consumed in etm4_hisi_match_pid().

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230710062500.45147-4-anshuman.khandual@arm.com

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index bf93147..e91e59e 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -66,7 +66,6 @@ static u64 etm4_get_access_type(struct etmv4_config *config);
 static enum cpuhp_state hp_online;
 
 struct etm4_init_arg {
-       unsigned int            pid;
        struct device           *dev;
        struct csdev_access     *csa;
 };
@@ -370,9 +369,17 @@ static void etm4_disable_arch_specific(struct etmv4_drvdata *drvdata)
 }
 
 static void etm4_check_arch_features(struct etmv4_drvdata *drvdata,
-                                     unsigned int id)
+                                    struct csdev_access *csa)
 {
-       if (etm4_hisi_match_pid(id))
+       /*
+        * TRCPIDR* registers are not required for ETMs with system
+        * instructions. They must be identified by the MIDR+REVIDRs.
+        * Skip the TRCPID checks for now.
+        */
+       if (!csa->io_mem)
+               return;
+
+       if (etm4_hisi_match_pid(coresight_get_pid(csa)))
                set_bit(ETM4_IMPDEF_HISI_CORE_COMMIT, drvdata->arch_features);
 }
 #else
@@ -385,7 +392,7 @@ static void etm4_disable_arch_specific(struct etmv4_drvdata *drvdata)
 }
 
 static void etm4_check_arch_features(struct etmv4_drvdata *drvdata,
-                                    unsigned int id)
+                                    struct csdev_access *csa)
 {
 }
 #endif /* CONFIG_ETM4X_IMPDEF_FEATURE */
@@ -1161,7 +1168,7 @@ static void etm4_init_arch_data(void *info)
        etm4_os_unlock_csa(drvdata, csa);
        etm4_cs_unlock(drvdata, csa);
 
-       etm4_check_arch_features(drvdata, init_arg->pid);
+       etm4_check_arch_features(drvdata, csa);
 
        /* find all capabilities of the tracing unit */
        etmidr0 = etm4x_relaxed_read32(csa, TRCIDR0);
@@ -2044,7 +2051,7 @@ static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg)
        return 0;
 }
 
-static int etm4_probe(struct device *dev, u32 etm_pid)
+static int etm4_probe(struct device *dev)
 {
        struct etmv4_drvdata *drvdata = dev_get_drvdata(dev);
        struct csdev_access access = { 0 };
@@ -2073,7 +2080,6 @@ static int etm4_probe(struct device *dev, u32 etm_pid)
 
        init_arg.dev = dev;
        init_arg.csa = &access;
-       init_arg.pid = etm_pid;
 
        /*
         * Serialize against CPUHP callbacks to avoid race condition
@@ -2120,7 +2126,7 @@ static int etm4_probe_amba(struct amba_device *adev, const struct amba_id *id)
 
        drvdata->base = base;
        dev_set_drvdata(dev, drvdata);
-       ret = etm4_probe(dev, id->id);
+       ret = etm4_probe(dev);
        if (!ret)
                pm_runtime_put(&adev->dev);
 
@@ -2142,12 +2148,7 @@ static int etm4_probe_platform_dev(struct platform_device *pdev)
        pm_runtime_set_active(&pdev->dev);
        pm_runtime_enable(&pdev->dev);
 
-       /*
-        * System register based devices could match the
-        * HW by reading appropriate registers on the HW
-        * and thus we could skip the PID.
-        */
-       ret = etm4_probe(&pdev->dev, 0);
+       ret = etm4_probe(&pdev->dev);
 
        pm_runtime_put(&pdev->dev);
        return ret;

diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index bf70987..255cfd2 100644 (file)
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -386,6 +386,18 @@ static inline u32 csdev_access_relaxed_read32(struct csdev_access *csa,
        return csa->read(offset, true, false);
 }
 
+#define CORESIGHT_PIDRn(i)     (0xFE0 + ((i) * 4))
+
+static inline u32 coresight_get_pid(struct csdev_access *csa)
+{
+       u32 i, pid = 0;
+
+       for (i = 0; i < 4; i++)
+               pid |= csdev_access_relaxed_read32(csa, CORESIGHT_PIDRn(i)) << (i * 8);
+
+       return pid;
+}
+
 static inline u64 csdev_access_relaxed_read_pair(struct csdev_access *csa,
                                                 u32 lo_offset, u32 hi_offset)
 {