Merge tag 'riscv-for-linus-5.20-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull more RISC-V updates from Palmer Dabbelt:
 "There's still a handful of new features in here, but there are a lot
  of fixes/cleanups as well:

   - Support for the Zicbom extension for explicit cache-block
     management, along with the necessary bits to make the non-standard
     cache management ops on the Allwinner D1 function

   - Support for the Zihintpause extension, which codifies a go-slow
     instruction used for cpu_relax()

   - Support for the Sstc extension for supervisor-mode timer/counter
     management

   - Many device tree fixes and cleanups, including a large set for the
     Canaan device trees

   - A handful of fixes and cleanups for the PMU driver"

* tag 'riscv-for-linus-5.20-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (43 commits)
  dt-bindings: gpio: sifive: add gpio-line-names
  wireguard: selftests: set CONFIG_NONPORTABLE on riscv32
  RISC-V: KVM: Support sstc extension
  RISC-V: Improve SBI definitions
  RISC-V: Move counter info definition to sbi header file
  RISC-V: Fix SBI PMU calls for RV32
  RISC-V: Update user page mapping only once during start
  RISC-V: Fix counter restart during overflow for RV32
  RISC-V: Prefer sstc extension if available
  RISC-V: Enable sstc extension parsing from DT
  RISC-V: Add SSTC extension CSR details
  riscv:uprobe fix SR_SPIE set/clear handling
  dt-bindings: riscv: fix SiFive l2-cache's cache-sets
  riscv: ensure cpu_ops_sbi is declared
  RISC-V: cpu_ops_spinwait.c should include head.h
  RISC-V: Declare cpu_ops_spinwait in <asm/cpu_ops.h>
  riscv: dts: starfive: correct number of external interrupts
  riscv: dts: sifive unmatched: Add PWM controlled LEDs
  riscv/purgatory: Omit use of bin2c
  riscv/purgatory: hard-code obj-y in Makefile
  ...

1 files changed, 24 insertions, 1 deletions

diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
index e460df7ed799..969a552da8d2 100644
--- a/drivers/clocksource/timer-riscv.c
+++ b/drivers/clocksource/timer-riscv.c
@@ -7,6 +7,9 @@
  * either be read from the "time" and "timeh" CSRs, and can use the SBI to
  * setup events, or directly accessed using MMIO registers.
  */
+
+#define pr_fmt(fmt) "riscv-timer: " fmt
+
 #include <linux/clocksource.h>
 #include <linux/clockchips.h>
 #include <linux/cpu.h>
@@ -20,14 +23,28 @@
 #include <linux/of_irq.h>
 #include <clocksource/timer-riscv.h>
 #include <asm/smp.h>
+#include <asm/hwcap.h>
 #include <asm/sbi.h>
 #include <asm/timex.h>
 
+static DEFINE_STATIC_KEY_FALSE(riscv_sstc_available);
+
 static int riscv_clock_next_event(unsigned long delta,
 		struct clock_event_device *ce)
 {
+	u64 next_tval = get_cycles64() + delta;
+
 	csr_set(CSR_IE, IE_TIE);
-	sbi_set_timer(get_cycles64() + delta);
+	if (static_branch_likely(&riscv_sstc_available)) {
+#if defined(CONFIG_32BIT)
+		csr_write(CSR_STIMECMP, next_tval & 0xFFFFFFFF);
+		csr_write(CSR_STIMECMPH, next_tval >> 32);
+#else
+		csr_write(CSR_STIMECMP, next_tval);
+#endif
+	} else
+		sbi_set_timer(next_tval);
+
 	return 0;
 }
 
@@ -166,6 +183,12 @@ static int __init riscv_timer_init_dt(struct device_node *n)
 	if (error)
 		pr_err("cpu hp setup state failed for RISCV timer [%d]\n",
 		       error);
+
+	if (riscv_isa_extension_available(NULL, SSTC)) {
+		pr_info("Timer interrupt in S-mode is available via sstc extension\n");
+		static_branch_enable(&riscv_sstc_available);
+	}
+
 	return error;
 }