Re: [PATCH v3 19/26] coresight: etm4x: Detect access early on the target CPU

On Wed, Oct 28, 2020 at 10:09:38PM +0000, Suzuki K Poulose wrote:

In preparation to detect the support for system instruction support, move the detection of the device access to the target CPU.

Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com

.../coresight/coresight-etm4x-core.c | 45 ++++++++++++++++--- 1 file changed, 40 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index f038bb10bc78..308674ab746c 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -56,6 +56,11 @@ static u64 etm4_get_access_type(struct etmv4_config *config); static enum cpuhp_state hp_online; +struct etm_init_arg {

s/etm_init_arg/etm4_init_arg

• struct etmv4_drvdata *drvdata;
• struct csdev_access *csa;

+};

u64 etm4x_sysreg_read(struct csdev_access *csa, u32 offset, bool _relaxed, @@ -669,6 +674,22 @@ static const struct coresight_ops etm4_cs_ops = { .source_ops = &etm4_source_ops, }; +static bool etm_init_iomem_access(struct etmv4_drvdata *drvdata,

• 		  struct csdev_access *csa)
  

+{

• *csa = CSDEV_ACCESS_IOMEM(drvdata->base);
• return true;

+}

+static bool etm_init_csdev_access(struct etmv4_drvdata *drvdata,

• 		  struct csdev_access *csa)
  

+{

• if (drvdata->base)

• return etm_init_iomem_access(drvdata, csa);
  

• return false;

+}

Returning a boolean rather than an int for the above two functions seems odd to me.

static void etm4_init_arch_data(void *info) { u32 etmidr0; @@ -677,11 +698,22 @@ static void etm4_init_arch_data(void *info) u32 etmidr3; u32 etmidr4; u32 etmidr5;

• struct etmv4_drvdata *drvdata = info;
• struct csdev_access tmp_csa = CSDEV_ACCESS_IOMEM(drvdata->base);
• struct csdev_access *csa = &tmp_csa;

• struct etm_init_arg *init_arg = info;
• struct etmv4_drvdata *drvdata;
• struct csdev_access *csa; int i;

• drvdata = init_arg->drvdata;
• csa = init_arg->csa;
• /*

• * If we are unable to detect the access mechanism,
  

• * or unable to detect the trace unit type, fail
  

• * early.
  

• */
  

• if (!etm_init_csdev_access(drvdata, csa))

• return;
  

• /* Make sure all registers are accessible */ etm4_os_unlock_csa(drvdata, csa); etm4_cs_unlock(drvdata, csa);

@@ -1524,6 +1556,7 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) struct etmv4_drvdata *drvdata; struct resource *res = &adev->res; struct coresight_desc desc = { 0 };

• struct etm_init_arg init_arg = { 0 };

drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL); if (!drvdata) @@ -1551,7 +1584,6 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) return PTR_ERR(base); drvdata->base = base;

• desc.access = CSDEV_ACCESS_IOMEM(base);

spin_lock_init(&drvdata->spinlock); @@ -1563,8 +1595,11 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id) if (!desc.name) return -ENOMEM;

• init_arg.drvdata = drvdata;
• init_arg.csa = &desc.access;
• if (smp_call_function_single(drvdata->cpu,

• 		etm4_init_arch_data,  drvdata, 1))
  

• 		etm4_init_arch_data,  &init_arg, 1))
  

  dev_err(dev, "ETM arch init failed\n");

if (etm4_arch_supported(drvdata->arch) == false) -- 2.24.1