lib: sbi_pmu: add callback for counter width

This patch adds a callback to fetch the number of bits implemented for a
custom firmware counter. If the callback fails or is not implemented then
width defaults to 63.

Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

diff --git a/include/sbi/sbi_pmu.h b/include/sbi/sbi_pmu.h
index c36524393bc09e41d3455f0b81c5c9473646859b..b3b75c1bad02b269c54ce461db514bb62978a60b 100644 (file)
--- a/include/sbi/sbi_pmu.h
+++ b/include/sbi/sbi_pmu.h
@@ -41,6 +41,11 @@ struct sbi_pmu_device {
        bool (*fw_counter_match_code)(uint32_t counter_index,
                                      uint32_t event_idx_code);
 
+       /**
+        * Fetch the max width of this counter in number of bits.
+        */
+       int (*fw_counter_width)(void);
+
        /**
         * Read value of custom firmware counter
         * Note: 0 <= counter_index < SBI_PMU_FW_CTR_MAX

diff --git a/lib/sbi/sbi_pmu.c b/lib/sbi/sbi_pmu.c
index 154dbdac549f433088c06b4a3f1f32c1c2e2b6bb..a99c04506f3637e88abb47a26f64d1e1249a65b4 100644 (file)
--- a/lib/sbi/sbi_pmu.c
+++ b/lib/sbi/sbi_pmu.c
@@ -761,6 +761,7 @@ unsigned long sbi_pmu_num_ctr(void)
 
 int sbi_pmu_ctr_get_info(uint32_t cidx, unsigned long *ctr_info)
 {
+       int width;
        union sbi_pmu_ctr_info cinfo = {0};
        struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
 
@@ -782,6 +783,11 @@ int sbi_pmu_ctr_get_info(uint32_t cidx, unsigned long *ctr_info)
                cinfo.type = SBI_PMU_CTR_TYPE_FW;
                /* Firmware counters are always 64 bits wide */
                cinfo.width = 63;
+               if (pmu_dev && pmu_dev->fw_counter_width) {
+                       width = pmu_dev->fw_counter_width();
+                       if (width)
+                               cinfo.width = width - 1;
+               }
        }
 
        *ctr_info = cinfo.value;