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Message-Id: <1398418275-9671-4-git-send-email-marc.zyngier@arm.com>
Date: Fri, 25 Apr 2014 10:31:11 +0100
From: Marc Zyngier <marc.zyngier@....com>
To: linux-kernel@...r.kernel.org, rtc-linux@...glegroups.com
Cc: Russell King <linux@....linux.org.uk>,
Will Deacon <will.deacon@....com>,
Catalin Marinas <catalin.marinas@....com>,
Alessandro Zummo <a.zummo@...ertech.it>
Subject: [PATCH 3/7] rtc-cmos: allow MMIO to be used when initialized from FDT
Currently, rtc-cmos mandates the use of an I/O port. If the
resource obtained from the device tree is instead a memory mapped
range, the probing will fail.
Let the cmos_of_init function try to ioremap the range obtained
from FDT. Should this fail, fallback to the normal I/O port.
Tested on KVM/ARM with kvmtools as the backend for RTC emulation.
Signed-off-by: Marc Zyngier <marc.zyngier@....com>
---
drivers/rtc/Kconfig | 3 +++
drivers/rtc/rtc-cmos.c | 67 ++++++++++++++++++++++++++++++++++++++++++-----
include/asm-generic/rtc.h | 5 ++++
3 files changed, 68 insertions(+), 7 deletions(-)
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 2e565f8..7e88866 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -677,6 +677,9 @@ config RTC_DRV_CMOS
This driver can also be built as a module. If so, the module
will be called rtc-cmos.
+config RTC_DRV_CMOS_MMIO
+ bool
+
config RTC_DRV_ALPHA
bool "Alpha PC-style CMOS"
depends on ALPHA
diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index be2dd17..d535e72 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -37,6 +37,7 @@
#include <linux/log2.h>
#include <linux/pm.h>
#include <linux/of.h>
+#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/dmi.h>
@@ -66,6 +67,41 @@ struct cmos_rtc {
static const char driver_name[] = "rtc_cmos";
+#ifdef CONFIG_RTC_DRV_CMOS_MMIO
+static void __iomem *rtc_cmos_base;
+
+static u8 do_cmos_read(u8 reg)
+{
+ u8 val;
+
+ if (rtc_cmos_base) {
+ writeb(reg, rtc_cmos_base);
+ val = readb(rtc_cmos_base + 1);
+ } else {
+ val = CMOS_READ(reg);
+ }
+
+ return val;
+}
+
+static void do_cmos_write(u8 val, u8 reg)
+{
+ if (rtc_cmos_base) {
+ writeb(reg, rtc_cmos_base);
+ writeb(val, rtc_cmos_base + 1);
+ } else {
+ CMOS_WRITE(val, reg);
+ }
+}
+
+static inline void rtc_cmos_set_base(void __iomem *base)
+{
+ rtc_cmos_base = base;
+}
+#else
+static void rtc_cmos_set_base(void __iomem *base) {}
+#endif
+
/* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;
* always mask it against the irq enable bits in RTC_CONTROL. Bit values
* are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.
@@ -663,13 +699,23 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
return -ENODEV;
/* Claim I/O ports ASAP, minimizing conflict with legacy driver.
- *
- * REVISIT non-x86 systems may instead use memory space resources
- * (needing ioremap etc), not i/o space resources like this ...
+ * MMIO gets requested the same way, not that it matters much.
*/
- ports = request_region(ports->start,
- resource_size(ports),
- driver_name);
+ switch(resource_type(ports)) {
+ case IORESOURCE_IO:
+ ports = request_region(ports->start,
+ resource_size(ports),
+ driver_name);
+ break;
+ case IORESOURCE_MEM:
+ ports = request_mem_region(ports->start,
+ resource_size(ports),
+ driver_name);
+ break;
+ default: /* Martian I/O??? */
+ ports = NULL;
+ }
+
if (!ports) {
dev_dbg(dev, "i/o registers already in use\n");
return -EBUSY;
@@ -1160,10 +1206,17 @@ static inline void cmos_of_init(struct platform_device *pdev) {}
static int __init cmos_platform_probe(struct platform_device *pdev)
{
+ struct resource *ports;
+
cmos_of_init(pdev);
+
+ ports = platform_get_resource(pdev, IORESOURCE_IO, 0);
+ if (!ports)
+ ports = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
cmos_wake_setup(&pdev->dev);
return cmos_do_probe(&pdev->dev,
- platform_get_resource(pdev, IORESOURCE_IO, 0),
+ ports,
platform_get_irq(pdev, 0));
}
diff --git a/include/asm-generic/rtc.h b/include/asm-generic/rtc.h
index 1ad3e78..236693b 100644
--- a/include/asm-generic/rtc.h
+++ b/include/asm-generic/rtc.h
@@ -28,6 +28,10 @@
#define RTC_24H 0x02 /* 24 hour mode - else hours bit 7 means pm */
#define RTC_DST_EN 0x01 /* auto switch DST - works f. USA only */
+#ifdef CONFIG_RTC_DRV_CMOS_MMIO
+static u8 do_cmos_read(u8 reg);
+static void do_cmos_write(u8 val, u8 reg);
+#else
static inline u8 do_cmos_read(u8 reg)
{
return CMOS_READ(reg);
@@ -37,6 +41,7 @@ static inline void do_cmos_write(u8 val, u8 reg)
{
CMOS_WRITE(val, reg);
}
+#endif
static inline unsigned long rtc_cmos_lock(void)
{
--
1.8.3.4
--
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