linux-kernel - [PATCH 1/3] ARM: at91: flush the L2 cache before entering cpu idle

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Date:   Fri, 6 Jan 2017 14:59:45 +0800
From:   Wenyou Yang <wenyou.yang@...el.com>
To:     Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
        Russell King <linux@....linux.org.uk>,
        Nicolas Ferre <nicolas.ferre@...el.com>,
        "Rob Herring" <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>
CC:     <linux-kernel@...r.kernel.org>,
        Wenyou Yang <wenyou.yang@...rochip.com>,
        <devicetree@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Wenyou Yang <wenyou.yang@...el.com>
Subject: [PATCH 1/3] ARM: at91: flush the L2 cache before entering cpu idle

For the SoCs such as SAMA5D2 and SAMA5D4 which have L2 cache,
flush the L2 cache first before entering the cpu idle.

Signed-off-by: Wenyou Yang <wenyou.yang@...el.com>
---

 arch/arm/mach-at91/pm.c       | 19 +++++++++++++++++++
 drivers/memory/atmel-sdramc.c |  1 +
 2 files changed, 20 insertions(+)

diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
index b4332b727e9c..1a60dede1a01 100644
--- a/arch/arm/mach-at91/pm.c
+++ b/arch/arm/mach-at91/pm.c
@@ -289,6 +289,24 @@ static void at91_ddr_standby(void)
 		at91_ramc_write(1, AT91_DDRSDRC_LPR, saved_lpr1);
 }
 
+static void at91_ddr_cache_standby(void)
+{
+	u32 saved_lpr;
+
+	flush_cache_all();
+	outer_disable();
+
+	saved_lpr = at91_ramc_read(0, AT91_DDRSDRC_LPR);
+	at91_ramc_write(0, AT91_DDRSDRC_LPR, (saved_lpr &
+			(~AT91_DDRSDRC_LPCB)) | AT91_DDRSDRC_LPCB_SELF_REFRESH);
+
+	cpu_do_idle();
+
+	at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr);
+
+	outer_resume();
+}
+
 /* We manage both DDRAM/SDRAM controllers, we need more than one value to
  * remember.
  */
@@ -324,6 +342,7 @@ static const struct of_device_id const ramc_ids[] __initconst = {
 	{ .compatible = "atmel,at91sam9260-sdramc", .data = at91sam9_sdram_standby },
 	{ .compatible = "atmel,at91sam9g45-ddramc", .data = at91_ddr_standby },
 	{ .compatible = "atmel,sama5d3-ddramc", .data = at91_ddr_standby },
+	{ .compatible = "atmel,sama5d4-ddramc", .data = at91_ddr_cache_standby },
 	{ /*sentinel*/ }
 };
 
diff --git a/drivers/memory/atmel-sdramc.c b/drivers/memory/atmel-sdramc.c
index b418b39af180..7e5c5c6c1348 100644
--- a/drivers/memory/atmel-sdramc.c
+++ b/drivers/memory/atmel-sdramc.c
@@ -48,6 +48,7 @@ static const struct of_device_id atmel_ramc_of_match[] = {
 	{ .compatible = "atmel,at91sam9260-sdramc", .data = &at91rm9200_caps, },
 	{ .compatible = "atmel,at91sam9g45-ddramc", .data = &at91sam9g45_caps, },
 	{ .compatible = "atmel,sama5d3-ddramc", .data = &sama5d3_caps, },
+	{ .compatible = "atmel,sama5d4-ddramc", .data = &sama5d3_caps, },
 	{},
 };
 
-- 
2.11.0