linux-kernel - [PATCH v2 3/5] clocksource/drivers/timer-riscv: Remove MMIO related stuff

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Date:   Sat, 27 Jun 2020 21:49:55 +0530
From:   Anup Patel <anup.patel@....com>
To:     Palmer Dabbelt <palmer@...belt.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Rob Herring <robh+dt@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     Damien Le Moal <damien.lemoal@....com>,
        Atish Patra <atish.patra@....com>,
        Alistair Francis <Alistair.Francis@....com>,
        Anup Patel <anup@...infault.org>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, Anup Patel <anup.patel@....com>
Subject: [PATCH v2 3/5] clocksource/drivers/timer-riscv: Remove MMIO related stuff

Right now the RISC-V timer is convoluted to support:
1. Linux RISC-V S-mode (with MMU) where it will use TIME CSR
   for clocksource and SBI timer calls for clockevent device.
2. Linux RISC-V M-mode (without MMU) where it will use CLINT
   MMIO counter register for clocksource and CLINT MMIO compare
   register for clockevent device.

This patch removes MMIO related stuff from RISC-V timer driver
so that we can have a separate CLINT timer driver.

Signed-off-by: Anup Patel <anup.patel@....com>
---
 arch/riscv/Kconfig                |  2 +-
 arch/riscv/include/asm/timex.h    | 28 +++++++---------------------
 drivers/clocksource/Kconfig       |  2 +-
 drivers/clocksource/timer-riscv.c | 17 ++---------------
 4 files changed, 11 insertions(+), 38 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 448a9952aa2f..868bbc4d0803 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -72,7 +72,7 @@ config RISCV
 	select PCI_DOMAINS_GENERIC if PCI
 	select PCI_MSI if PCI
 	select RISCV_INTC
-	select RISCV_TIMER
+	select RISCV_TIMER if RISCV_SBI
 	select SPARSEMEM_STATIC if 32BIT
 	select SPARSE_IRQ
 	select SYSCTL_EXCEPTION_TRACE
diff --git a/arch/riscv/include/asm/timex.h b/arch/riscv/include/asm/timex.h
index bad2a7c2cda5..a3fb85d505d4 100644
--- a/arch/riscv/include/asm/timex.h
+++ b/arch/riscv/include/asm/timex.h
@@ -7,41 +7,27 @@
 #define _ASM_RISCV_TIMEX_H
 
 #include <asm/csr.h>
-#include <asm/mmio.h>
 
 typedef unsigned long cycles_t;
 
-extern u64 __iomem *riscv_time_val;
-extern u64 __iomem *riscv_time_cmp;
-
-#ifdef CONFIG_64BIT
-#define mmio_get_cycles()	readq_relaxed(riscv_time_val)
-#else
-#define mmio_get_cycles()	readl_relaxed(riscv_time_val)
-#define mmio_get_cycles_hi()	readl_relaxed(((u32 *)riscv_time_val) + 1)
-#endif
-
 static inline cycles_t get_cycles(void)
 {
-	if (IS_ENABLED(CONFIG_RISCV_SBI))
-		return csr_read(CSR_TIME);
-	return mmio_get_cycles();
+	return csr_read(CSR_TIME);
 }
 #define get_cycles get_cycles
 
+static inline u32 get_cycles_hi(void)
+{
+	return csr_read(CSR_TIMEH);
+}
+#define get_cycles_hi get_cycles_hi
+
 #ifdef CONFIG_64BIT
 static inline u64 get_cycles64(void)
 {
 	return get_cycles();
 }
 #else /* CONFIG_64BIT */
-static inline u32 get_cycles_hi(void)
-{
-	if (IS_ENABLED(CONFIG_RISCV_SBI))
-		return csr_read(CSR_TIMEH);
-	return mmio_get_cycles_hi();
-}
-
 static inline u64 get_cycles64(void)
 {
 	u32 hi, lo;
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 91418381fcd4..8c6a0f1274af 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -649,7 +649,7 @@ config ATCPIT100_TIMER
 
 config RISCV_TIMER
 	bool "Timer for the RISC-V platform"
-	depends on GENERIC_SCHED_CLOCK && RISCV
+	depends on GENERIC_SCHED_CLOCK && RISCV_SBI
 	default y
 	select TIMER_PROBE
 	select TIMER_OF
diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
index 9de1dabfb126..c51c5ed15aa7 100644
--- a/drivers/clocksource/timer-riscv.c
+++ b/drivers/clocksource/timer-riscv.c
@@ -19,26 +19,13 @@
 #include <linux/of_irq.h>
 #include <asm/smp.h>
 #include <asm/sbi.h>
-
-u64 __iomem *riscv_time_cmp;
-u64 __iomem *riscv_time_val;
-
-static inline void mmio_set_timer(u64 val)
-{
-	void __iomem *r;
-
-	r = riscv_time_cmp + cpuid_to_hartid_map(smp_processor_id());
-	writeq_relaxed(val, r);
-}
+#include <asm/timex.h>
 
 static int riscv_clock_next_event(unsigned long delta,
 		struct clock_event_device *ce)
 {
 	csr_set(CSR_IE, IE_TIE);
-	if (IS_ENABLED(CONFIG_RISCV_SBI))
-		sbi_set_timer(get_cycles64() + delta);
-	else
-		mmio_set_timer(get_cycles64() + delta);
+	sbi_set_timer(get_cycles64() + delta);
 	return 0;
 }
 
-- 
2.25.1