lib: utils/timer: Add Andes fdt timer support

Since we can get the PLMT base address and timer frequency from
device tree, move plmt timer device to fdt timer framework.

dts example (Quad-core AX45MP):

  cpus {
      ...
      timebase-frequency = <0x3938700>;
      ...
  }
  soc {
      ...
      plmt0@e6000000 {
          compatible = "andestech,plmt0";
          reg = <0x00 0xe6000000 0x00 0x100000>;
          interrupts-extended = <&cpu0_intc 0x07
                                 &cpu1_intc 0x07
                                 &cpu2_intc 0x07
                                 &cpu3_intc 0x07>;
      };
      ...
  }

Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

lib/utils/timer/Kconfig

@@ -14,10 +14,19 @@ config FDT_TIMER_MTIMER
 	select TIMER_MTIMER
 	default n
 
+config FDT_TIMER_PLMT
+	bool "Andes PLMT FDT driver"
+	select TIMER_PLMT
+	default n
+
 endif
 
 config TIMER_MTIMER
 	bool "ACLINT MTIMER support"
 	default n
 
+config TIMER_PLMT
+	bool "Andes PLMT support"
+	default n
+
 endmenu

lib/utils/timer/andes_plmt.c

@@ -0,0 +1,104 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2022 Andes Technology Corporation
+ *
+ * Authors:
+ *   Yu Chien Peter Lin <peterlin@andestech.com>
+ */
+
+#include <sbi/riscv_asm.h>
+#include <sbi/riscv_io.h>
+#include <sbi/sbi_domain.h>
+#include <sbi/sbi_error.h>
+#include <sbi/sbi_timer.h>
+#include <sbi_utils/timer/andes_plmt.h>
+
+struct plmt_data plmt;
+
+static u64 plmt_timer_value(void)
+{
+#if __riscv_xlen == 64
+	return readq_relaxed(plmt.time_val);
+#else
+	u32 lo, hi;
+
+	do {
+		hi = readl_relaxed((void *)plmt.time_val + 0x04);
+		lo = readl_relaxed(plmt.time_val);
+	} while (hi != readl_relaxed((void *)plmt.time_val + 0x04));
+
+	return ((u64)hi << 32) | (u64)lo;
+#endif
+}
+
+static void plmt_timer_event_stop(void)
+{
+	u32 target_hart = current_hartid();
+
+	if (plmt.hart_count <= target_hart)
+		ebreak();
+
+	/* Clear PLMT Time Compare */
+#if __riscv_xlen == 64
+	writeq_relaxed(-1ULL, &plmt.time_cmp[target_hart]);
+#else
+	writel_relaxed(-1UL, &plmt.time_cmp[target_hart]);
+	writel_relaxed(-1UL, (void *)(&plmt.time_cmp[target_hart]) + 0x04);
+#endif
+}
+
+static void plmt_timer_event_start(u64 next_event)
+{
+	u32 target_hart = current_hartid();
+
+	if (plmt.hart_count <= target_hart)
+		ebreak();
+
+	/* Program PLMT Time Compare */
+#if __riscv_xlen == 64
+	writeq_relaxed(next_event, &plmt.time_cmp[target_hart]);
+#else
+	u32 mask = -1UL;
+
+	writel_relaxed(next_event & mask, &plmt.time_cmp[target_hart]);
+	writel_relaxed(next_event >> 32,
+		       (void *)(&plmt.time_cmp[target_hart]) + 0x04);
+#endif
+}
+
+static struct sbi_timer_device plmt_timer = {
+	.name		   = "andes_plmt",
+	.timer_freq	   = DEFAULT_AE350_PLMT_FREQ,
+	.timer_value	   = plmt_timer_value,
+	.timer_event_start = plmt_timer_event_start,
+	.timer_event_stop  = plmt_timer_event_stop
+};
+
+int plmt_cold_timer_init(struct plmt_data *plmt)
+{
+	int rc;
+
+	/* Add PLMT region to the root domain */
+	rc = sbi_domain_root_add_memrange(
+		(unsigned long)plmt->time_val, plmt->size, PLMT_REGION_ALIGN,
+		SBI_DOMAIN_MEMREGION_MMIO | SBI_DOMAIN_MEMREGION_READABLE);
+	if (rc)
+		return rc;
+
+	plmt_timer.timer_freq = plmt->timer_freq;
+
+	sbi_timer_set_device(&plmt_timer);
+
+	return 0;
+}
+
+int plmt_warm_timer_init(void)
+{
+	if (!plmt.time_val)
+		return SBI_ENODEV;
+
+	plmt_timer_event_stop();
+
+	return 0;
+}

lib/utils/timer/fdt_timer_plmt.c

@@ -0,0 +1,51 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2022 Andes Technology Corporation
+ *
+ * Authors:
+ *   Yu Chien Peter Lin <peterlin@andestech.com>
+ */
+
+#include <sbi_utils/fdt/fdt_helper.h>
+#include <sbi_utils/timer/fdt_timer.h>
+#include <sbi_utils/timer/andes_plmt.h>
+
+extern struct plmt_data plmt;
+
+static int fdt_plmt_cold_timer_init(void *fdt, int nodeoff,
+				    const struct fdt_match *match)
+{
+	int rc;
+	unsigned long plmt_base;
+
+	rc = fdt_parse_plmt_node(fdt, nodeoff, &plmt_base, &plmt.size,
+				 &plmt.hart_count);
+	if (rc)
+		return rc;
+
+	plmt.time_val = (u64 *)plmt_base;
+	plmt.time_cmp = (u64 *)(plmt_base + 0x8);
+
+	rc = fdt_parse_timebase_frequency(fdt, &plmt.timer_freq);
+	if (rc)
+		return rc;
+
+	rc = plmt_cold_timer_init(&plmt);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
+static const struct fdt_match timer_plmt_match[] = {
+	{ .compatible = "andestech,plmt0" },
+	{},
+};
+
+struct fdt_timer fdt_timer_plmt = {
+	.match_table = timer_plmt_match,
+	.cold_init   = fdt_plmt_cold_timer_init,
+	.warm_init   = plmt_warm_timer_init,
+	.exit	     = NULL,
+};

lib/utils/timer/objects.mk

@@ -8,9 +8,13 @@
 #
 
 libsbiutils-objs-$(CONFIG_TIMER_MTIMER) += timer/aclint_mtimer.o
+libsbiutils-objs-$(CONFIG_TIMER_PLMT) += timer/andes_plmt.o
 
 libsbiutils-objs-$(CONFIG_FDT_TIMER) += timer/fdt_timer.o
 libsbiutils-objs-$(CONFIG_FDT_TIMER) += timer/fdt_timer_drivers.o
 
 carray-fdt_timer_drivers-$(CONFIG_FDT_TIMER_MTIMER) += fdt_timer_mtimer
 libsbiutils-objs-$(CONFIG_FDT_TIMER_MTIMER) += timer/fdt_timer_mtimer.o
+
+carray-fdt_timer_drivers-$(CONFIG_FDT_TIMER_PLMT) += fdt_timer_plmt
+libsbiutils-objs-$(CONFIG_FDT_TIMER_PLMT) += timer/fdt_timer_plmt.o