Accessing the HW configuration register each time the memory width is needed simply doesn't make sense. It is much more efficient to read the value once and keep a reference for later use.
Signed-off-by: Mathieu Poirier <mathieu.poir...@linaro.org> --- drivers/hwtracing/coresight/coresight-tmc-etf.c | 14 +--------- drivers/hwtracing/coresight/coresight-tmc.c | 34 +++++++++++++++++++++++++ drivers/hwtracing/coresight/coresight-tmc.h | 10 +++++--- 3 files changed, 41 insertions(+), 17 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c index cc88c15ba45c..981c5ca75e36 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c @@ -41,25 +41,13 @@ void tmc_etb_enable_hw(struct tmc_drvdata *drvdata) static void tmc_etb_dump_hw(struct tmc_drvdata *drvdata) { - enum tmc_mem_intf_width memwidth; - u8 memwords; char *bufp; u32 read_data; int i; - memwidth = BMVAL(readl_relaxed(drvdata->base + CORESIGHT_DEVID), 8, 10); - if (memwidth == TMC_MEM_INTF_WIDTH_32BITS) - memwords = 1; - else if (memwidth == TMC_MEM_INTF_WIDTH_64BITS) - memwords = 2; - else if (memwidth == TMC_MEM_INTF_WIDTH_128BITS) - memwords = 4; - else - memwords = 8; - bufp = drvdata->buf; while (1) { - for (i = 0; i < memwords; i++) { + for (i = 0; i < drvdata->memwidth; i++) { read_data = readl_relaxed(drvdata->base + TMC_RRD); if (read_data == 0xFFFFFFFF) return; diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c index 55806352b1f1..cb030a09659d 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.c +++ b/drivers/hwtracing/coresight/coresight-tmc.c @@ -193,6 +193,39 @@ static const struct file_operations tmc_fops = { .llseek = no_llseek, }; +static enum tmc_mem_intf_width tmc_get_memwidth(u32 devid) +{ + enum tmc_mem_intf_width memwidth; + + /* + * Excerpt from the TRM: + * + * DEVID::MEMWIDTH[10:8] + * 0x2 Memory interface databus is 32 bits wide. + * 0x3 Memory interface databus is 64 bits wide. + * 0x4 Memory interface databus is 128 bits wide. + * 0x5 Memory interface databus is 256 bits wide. + */ + switch (BMVAL(devid, 8, 10)) { + case 0x2: + memwidth = TMC_MEM_INTF_WIDTH_32BITS; + break; + case 0x3: + memwidth = TMC_MEM_INTF_WIDTH_64BITS; + break; + case 0x4: + memwidth = TMC_MEM_INTF_WIDTH_128BITS; + break; + case 0x5: + memwidth = TMC_MEM_INTF_WIDTH_256BITS; + break; + default: + memwidth = 0; + } + + return memwidth; +} + #define coresight_tmc_simple_func(name, offset) \ coresight_simple_func(struct tmc_drvdata, name, offset) @@ -306,6 +339,7 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id) devid = readl_relaxed(drvdata->base + CORESIGHT_DEVID); drvdata->config_type = BMVAL(devid, 6, 7); + drvdata->memwidth = tmc_get_memwidth(devid); if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) { if (np) diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h index 9b4c215d2b6b..12a097f3d06c 100644 --- a/drivers/hwtracing/coresight/coresight-tmc.h +++ b/drivers/hwtracing/coresight/coresight-tmc.h @@ -81,10 +81,10 @@ enum tmc_mode { }; enum tmc_mem_intf_width { - TMC_MEM_INTF_WIDTH_32BITS = 0x2, - TMC_MEM_INTF_WIDTH_64BITS = 0x3, - TMC_MEM_INTF_WIDTH_128BITS = 0x4, - TMC_MEM_INTF_WIDTH_256BITS = 0x5, + TMC_MEM_INTF_WIDTH_32BITS = 1, + TMC_MEM_INTF_WIDTH_64BITS = 2, + TMC_MEM_INTF_WIDTH_128BITS = 4, + TMC_MEM_INTF_WIDTH_256BITS = 8, }; /** @@ -101,6 +101,7 @@ enum tmc_mem_intf_width { * @size: @buf size. * @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. * @trigger_cntr: amount of words to store after a trigger. */ struct tmc_drvdata { @@ -117,6 +118,7 @@ struct tmc_drvdata { u32 size; local_t mode; enum tmc_config_type config_type; + enum tmc_mem_intf_width memwidth; u32 trigger_cntr; }; -- 2.5.0