Re: [PATCH 2/2] coresight: tmc: Configure AXI write burst size

On Wed, 1 Sept 2021 at 14:12, Tanmay Jagdale tanmay@marvell.com wrote:

The current driver sets the write burst size initiated by TMC-ETR on AXI bus to a fixed value of 16. Make this configurable by reading the value specified in fwnode. If not specified, then default to 16.

Introduced a "max_burst_size" variable in tmc_drvdata structure to facilitate this change.

Signed-off-by: Tanmay Jagdale tanmay@marvell.com

.../hwtracing/coresight/coresight-tmc-core.c | 21 +++++++++++++++++-- .../hwtracing/coresight/coresight-tmc-etr.c | 3 ++- drivers/hwtracing/coresight/coresight-tmc.h | 6 +++++- 3 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c index 74c6323d4d6a..d0276af82494 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-core.c +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c @@ -432,6 +432,21 @@ static u32 tmc_etr_get_default_buffer_size(struct device *dev) return size; }

+static u32 tmc_etr_get_max_burst_size(struct device *dev) +{

•   u32 burst_size;
  

•   if (fwnode_property_read_u32(dev->fwnode, "arm,max-burst-size",
  

•                                &burst_size))
  

•           return TMC_AXICTL_WR_BURST_16;
  

•   /* Only permissible values are 0 to 15 */
  

•   if (burst_size > 0xF)
  

•           burst_size = TMC_AXICTL_WR_BURST_16;
  

•   return burst_size;
  

+}

static int tmc_probe(struct amba_device *adev, const struct amba_id *id) { int ret = 0; @@ -469,10 +484,12 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id) /* This device is not associated with a session */ drvdata->pid = -1;

•   if (drvdata->config_type == TMC_CONFIG_TYPE_ETR)
  

•   if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
            drvdata->size = tmc_etr_get_default_buffer_size(dev);
  

•   else
  

•           drvdata->max_burst_size = tmc_etr_get_max_burst_size(dev);
  

•   } else {
            drvdata->size = readl_relaxed(drvdata->base + TMC_RSZ) * 4;
  

•   }
  
    desc.dev = dev;
    desc.groups = coresight_tmc_groups;
  

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index acdb59e0e661..0ac2a611110b 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -982,7 +982,8 @@ static void __tmc_etr_enable_hw(struct tmc_drvdata *drvdata)

    axictl = readl_relaxed(drvdata->base + TMC_AXICTL);
    axictl &= ~TMC_AXICTL_CLEAR_MASK;

•   axictl |= (TMC_AXICTL_PROT_CTL_B1 | TMC_AXICTL_WR_BURST_16);
  

•   axictl |= TMC_AXICTL_PROT_CTL_B1;
  

•   axictl |= TMC_AXICTL_WR_BURST(drvdata->max_burst_size);
    axictl |= TMC_AXICTL_AXCACHE_OS;
  
    if (tmc_etr_has_cap(drvdata, TMC_ETR_AXI_ARCACHE)) {
  

diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h index b91ec7dde7bc..6bec20a392b3 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.h +++ b/drivers/hwtracing/coresight/coresight-tmc.h @@ -70,7 +70,8 @@ #define TMC_AXICTL_PROT_CTL_B0 BIT(0) #define TMC_AXICTL_PROT_CTL_B1 BIT(1) #define TMC_AXICTL_SCT_GAT_MODE BIT(7) -#define TMC_AXICTL_WR_BURST_16 0xF00 +#define TMC_AXICTL_WR_BURST(v) (((v) & 0xf) << 8) +#define TMC_AXICTL_WR_BURST_16 0xf /* Write-back Read and Write-allocate */ #define TMC_AXICTL_AXCACHE_OS (0xf << 2) #define TMC_AXICTL_ARCACHE_OS (0xf << 16) @@ -174,6 +175,8 @@ struct etr_buf {

• @etr_buf: details of buffer used in TMC-ETR
• @len: size of the available trace for ETF/ETB.
• @size: trace buffer size for this TMC (common for all modes).

• • @max_burst_size: The maximum burst size that can be initiated by

• •         TMC-ETR on AXI bus.
    

  • @mode: how this TMC is being used.
  • @config_type: TMC variant, must be of type @tmc_config_type.
  • @memwidth: width of the memory interface databus, in bytes.

@@ -198,6 +201,7 @@ struct tmc_drvdata { }; u32 len; u32 size;

•   u32                     max_burst_size;
    u32                     mode;
    enum tmc_config_type    config_type;
    enum tmc_mem_intf_width memwidth;
  

-- 2.25.1

Reviewed-by: Mike Leach mike.leach@linaro.org