[PATCH v4 14/30] arm64: Add support for timer initialization through ACPI

[Nikos Nikoleris <nikos.nikoleris@arm.com>]

For systems with ACPI support, we can discover timers through the ACPI
GTDT table. This change implements the code to discover timers through
the GTDT and adds ACPI support in timer_save_state. This change
retains the default behavior; we check if a valid DT is provided, if
not, we try to discover timers using ACPI.

Signed-off-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
 arm/Makefile.common |  1 +
 arm/micro-bench.c   |  4 +-
 arm/timer.c         | 10 ++---
 lib/acpi.h          | 18 +++++++++
 lib/arm/asm/timer.h |  2 +
 lib/arm/setup.c     | 39 -------------------
 lib/arm/timer.c     | 92 +++++++++++++++++++++++++++++++++++++++++++++
 7 files changed, 120 insertions(+), 46 deletions(-)
 create mode 100644 lib/arm/timer.c

diff --git a/arm/Makefile.common b/arm/Makefile.common
index 3a726c20..c02dd906 100644
--- a/arm/Makefile.common
+++ b/arm/Makefile.common
@@ -53,6 +53,7 @@ cflatobjs += lib/arm/psci.o
 cflatobjs += lib/arm/smp.o
 cflatobjs += lib/arm/delay.o
 cflatobjs += lib/arm/gic.o lib/arm/gic-v2.o lib/arm/gic-v3.o
+cflatobjs += lib/arm/timer.o
 
 ifeq ($(CONFIG_EFI),y)
 cflatobjs += lib/acpi.o
diff --git a/arm/micro-bench.c b/arm/micro-bench.c
index 84366125..5be9b189 100644
--- a/arm/micro-bench.c
+++ b/arm/micro-bench.c
@@ -43,7 +43,7 @@ static void gic_irq_handler(struct pt_regs *regs)
 	irq_received = true;
 	gic_write_eoir(irqstat);
 
-	if (irqstat == PPI(TIMER_VTIMER_IRQ)) {
+	if (irqstat == TIMER_VTIMER_IRQ) {
 		write_sysreg((ARCH_TIMER_CTL_IMASK | ARCH_TIMER_CTL_ENABLE),
 			     cntv_ctl_el0);
 		isb();
@@ -229,7 +229,7 @@ static bool timer_prep(void)
 		assert_msg(0, "Unreachable");
 	}
 
-	writel(1 << PPI(TIMER_VTIMER_IRQ), gic_isenabler);
+	writel(1 << TIMER_VTIMER_IRQ, gic_isenabler);
 	write_sysreg(ARCH_TIMER_CTL_IMASK | ARCH_TIMER_CTL_ENABLE, cntv_ctl_el0);
 	isb();
 
diff --git a/arm/timer.c b/arm/timer.c
index c4e7b10f..a4a82812 100644
--- a/arm/timer.c
+++ b/arm/timer.c
@@ -139,7 +139,7 @@ static struct timer_info ptimer_info = {
 
 static void set_timer_irq_enabled(struct timer_info *info, bool enabled)
 {
-	u32 val = 1 << PPI(info->irq);
+	u32 val = 1 << info->irq;
 
 	if (enabled)
 		writel(val, gic_isenabler);
@@ -153,9 +153,9 @@ static void irq_handler(struct pt_regs *regs)
 	u32 irqstat = gic_read_iar();
 	u32 irqnr = gic_iar_irqnr(irqstat);
 
-	if (irqnr == PPI(vtimer_info.irq)) {
+	if (irqnr == vtimer_info.irq) {
 		info = &vtimer_info;
-	} else if (irqnr == PPI(ptimer_info.irq)) {
+	} else if (irqnr == ptimer_info.irq) {
 		info = &ptimer_info;
 	} else {
 		if (irqnr != GICC_INT_SPURIOUS)
@@ -185,9 +185,9 @@ static bool gic_timer_check_state(struct timer_info *info,
 	/* Wait for up to 1s for the GIC to sample the interrupt. */
 	for (i = 0; i < 10; i++) {
 		mdelay(100);
-		if (gic_irq_state(PPI(info->irq)) == expected_state) {
+		if (gic_irq_state(info->irq) == expected_state) {
 			mdelay(100);
-			if (gic_irq_state(PPI(info->irq)) == expected_state)
+			if (gic_irq_state(info->irq) == expected_state)
 				return true;
 		}
 	}
diff --git a/lib/acpi.h b/lib/acpi.h
index 02ca8958..9d974ee2 100644
--- a/lib/acpi.h
+++ b/lib/acpi.h
@@ -18,6 +18,7 @@
 #define FACP_SIGNATURE ACPI_SIGNATURE('F','A','C','P')
 #define FACS_SIGNATURE ACPI_SIGNATURE('F','A','C','S')
 #define SPCR_SIGNATURE ACPI_SIGNATURE('S','P','C','R')
+#define GTDT_SIGNATURE ACPI_SIGNATURE('G','T','D','T')
 
 #define ACPI_SIGNATURE_8BYTE(c1, c2, c3, c4, c5, c6, c7, c8) \
 	(((uint64_t)(ACPI_SIGNATURE(c1, c2, c3, c4))) |	     \
@@ -170,6 +171,23 @@ struct spcr_descriptor {
 	u32 reserved2;
 };
 
+struct acpi_table_gtdt {
+	ACPI_TABLE_HEADER_DEF	/* ACPI common table header */
+	u64 counter_block_addresss;
+	u32 reserved;
+	u32 secure_el1_interrupt;
+	u32 secure_el1_flags;
+	u32 non_secure_el1_interrupt;
+	u32 non_secure_el1_flags;
+	u32 virtual_timer_interrupt;
+	u32 virtual_timer_flags;
+	u32 non_secure_el2_interrupt;
+	u32 non_secure_el2_flags;
+	u64 counter_read_block_address;
+	u32 platform_timer_count;
+	u32 platform_timer_offset;
+};
+
 #pragma pack(0)
 
 void set_efi_rsdp(struct acpi_table_rsdp *rsdp);
diff --git a/lib/arm/asm/timer.h b/lib/arm/asm/timer.h
index f75cc67f..aaf839fc 100644
--- a/lib/arm/asm/timer.h
+++ b/lib/arm/asm/timer.h
@@ -27,5 +27,7 @@ extern struct timer_state __timer_state;
 #define TIMER_PTIMER_IRQ (__timer_state.ptimer.irq)
 #define TIMER_VTIMER_IRQ (__timer_state.vtimer.irq)
 
+void timer_save_state(void);
+
 #endif /* !__ASSEMBLY__ */
 #endif /* _ASMARM_TIMER_H_ */
diff --git a/lib/arm/setup.c b/lib/arm/setup.c
index bcdf0d78..1572c64e 100644
--- a/lib/arm/setup.c
+++ b/lib/arm/setup.c
@@ -35,8 +35,6 @@
 
 extern unsigned long etext;
 
-struct timer_state __timer_state;
-
 char *initrd;
 u32 initrd_size;
 
@@ -199,43 +197,6 @@ static void mem_init(phys_addr_t freemem_start)
 	page_alloc_ops_enable();
 }
 
-static void timer_save_state(void)
-{
-	const struct fdt_property *prop;
-	const void *fdt = dt_fdt();
-	int node, len;
-	u32 *data;
-
-	node = fdt_node_offset_by_compatible(fdt, -1, "arm,armv8-timer");
-	assert(node >= 0 || node == -FDT_ERR_NOTFOUND);
-
-	if (node == -FDT_ERR_NOTFOUND) {
-		__timer_state.ptimer.irq = -1;
-		__timer_state.vtimer.irq = -1;
-		return;
-	}
-
-	/*
-	 * From Linux devicetree timer binding documentation
-	 *
-	 * interrupts <type irq flags>:
-	 *	secure timer irq
-	 *	non-secure timer irq		(ptimer)
-	 *	virtual timer irq		(vtimer)
-	 *	hypervisor timer irq
-	 */
-	prop = fdt_get_property(fdt, node, "interrupts", &len);
-	assert(prop && len == (4 * 3 * sizeof(u32)));
-
-	data = (u32 *)prop->data;
-	assert(fdt32_to_cpu(data[3]) == 1 /* PPI */);
-	__timer_state.ptimer.irq = fdt32_to_cpu(data[4]);
-	__timer_state.ptimer.irq_flags = fdt32_to_cpu(data[5]);
-	assert(fdt32_to_cpu(data[6]) == 1 /* PPI */);
-	__timer_state.vtimer.irq = fdt32_to_cpu(data[7]);
-	__timer_state.vtimer.irq_flags = fdt32_to_cpu(data[8]);
-}
-
 void setup(const void *fdt, phys_addr_t freemem_start)
 {
 	void *freemem;
diff --git a/lib/arm/timer.c b/lib/arm/timer.c
new file mode 100644
index 00000000..ae702e41
--- /dev/null
+++ b/lib/arm/timer.c
@@ -0,0 +1,92 @@
+/*
+ * Initialize timers.
+ *
+ * Copyright (C) 2022, Arm Ltd., Nikos Nikoleris <nikos.nikoleris@arm.com>
+ * Copyright (C) 2014, Red Hat Inc, Andrew Jones <drjones@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+#include <libcflat.h>
+#include <acpi.h>
+#include <devicetree.h>
+#include <libfdt/libfdt.h>
+#include <asm/gic.h>
+#include <asm/timer.h>
+
+struct timer_state __timer_state;
+
+static void timer_save_state_fdt(void)
+{
+	const struct fdt_property *prop;
+	const void *fdt = dt_fdt();
+	int node, len;
+	u32 *data;
+
+	node = fdt_node_offset_by_compatible(fdt, -1, "arm,armv8-timer");
+	assert(node >= 0 || node == -FDT_ERR_NOTFOUND);
+
+	if (node == -FDT_ERR_NOTFOUND) {
+		__timer_state.ptimer.irq = -1;
+		__timer_state.vtimer.irq = -1;
+		return;
+	}
+
+	/*
+	 * From Linux devicetree timer binding documentation
+	 *
+	 * interrupts <type irq flags>:
+	 *      secure timer irq
+	 *      non-secure timer irq            (ptimer)
+	 *      virtual timer irq               (vtimer)
+	 *      hypervisor timer irq
+	 */
+	prop = fdt_get_property(fdt, node, "interrupts", &len);
+	assert(prop && len == (4 * 3 * sizeof(u32)));
+
+	data = (u32 *) prop->data;
+	assert(fdt32_to_cpu(data[3]) == 1 /* PPI */ );
+	__timer_state.ptimer.irq = PPI(fdt32_to_cpu(data[4]));
+	__timer_state.ptimer.irq_flags = fdt32_to_cpu(data[5]);
+	assert(fdt32_to_cpu(data[6]) == 1 /* PPI */ );
+	__timer_state.vtimer.irq = PPI(fdt32_to_cpu(data[7]));
+	__timer_state.vtimer.irq_flags = fdt32_to_cpu(data[8]);
+}
+
+#ifdef CONFIG_EFI
+
+#include <acpi.h>
+
+static void timer_save_state_acpi(void)
+{
+	struct acpi_table_gtdt *gtdt = find_acpi_table_addr(GTDT_SIGNATURE);
+
+	if (!gtdt) {
+		printf("Cannot find ACPI GTDT");
+		__timer_state.ptimer.irq = -1;
+		__timer_state.vtimer.irq = -1;
+		return;
+	}
+
+	__timer_state.ptimer.irq = gtdt->non_secure_el1_interrupt;
+	__timer_state.ptimer.irq_flags = gtdt->non_secure_el1_flags;
+
+	__timer_state.vtimer.irq = gtdt->virtual_timer_interrupt;
+	__timer_state.vtimer.irq_flags = gtdt->virtual_timer_flags;
+}
+
+#else
+
+static void timer_save_state_acpi(void)
+{
+	assert_msg(false, "ACPI not available");
+}
+
+#endif
+
+void timer_save_state(void)
+{
+	if (dt_available())
+		timer_save_state_fdt();
+	else
+		timer_save_state_acpi();
+}
-- 
2.25.1