Linux-Watchdog Archive on lore.kernel.org
 help / color / Atom feed
From: Ivan Mikhaylov <i.mikhaylov@yadro.com>
To: Guenter Roeck <linux@roeck-us.net>,
	Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Joel Stanley <joel@jms.id.au>, Andrew Jeffery <andrew@aj.id.au>,
	<linux-watchdog@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-aspeed@lists.ozlabs.org>, <linux-kernel@vger.kernel.org>,
	Alexander Amelkin <a.amelkin@yadro.com>,
	<openbmc@lists.ozlabs.org>, Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>, <devicetree@vger.kernel.org>,
	Ivan Mikhaylov <i.mikhaylov@yadro.com>
Subject: [PATCH v2 3/4] watchdog/aspeed: add support for dual boot
Date: Mon, 26 Aug 2019 13:46:35 +0300
Message-ID: <20190826104636.19324-4-i.mikhaylov@yadro.com> (raw)
In-Reply-To: <20190826104636.19324-1-i.mikhaylov@yadro.com>

Set WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION into WDT_CLEAR_TIMEOUT_STATUS
to clear out boot code source and re-enable access to the primary SPI flash
chip while booted via wdt2 from the alternate chip.

AST2400 datasheet says:
"In the 2nd flash booting mode, all the address mapping to CS0# would be
re-directed to CS1#. And CS0# is not accessable under this mode. To access
CS0#, firmware should clear the 2nd boot mode register in the WDT2 status
register WDT30.bit[1]."

Signed-off-by: Ivan Mikhaylov <i.mikhaylov@yadro.com>
---
 drivers/watchdog/aspeed_wdt.c | 62 ++++++++++++++++++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index cc71861e033a..bbc42847c0e3 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -53,6 +53,8 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
 #define   WDT_CTRL_ENABLE		BIT(0)
 #define WDT_TIMEOUT_STATUS	0x10
 #define   WDT_TIMEOUT_STATUS_BOOT_SECONDARY	BIT(1)
+#define WDT_CLEAR_TIMEOUT_STATUS	0x14
+#define   WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION	BIT(0)
 
 /*
  * WDT_RESET_WIDTH controls the characteristics of the external pulse (if
@@ -165,6 +167,57 @@ static int aspeed_wdt_restart(struct watchdog_device *wdd,
 	return 0;
 }
 
+/* access_cs0 shows if cs0 is accessible, hence the reverted bit */
+static ssize_t access_cs0_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct aspeed_wdt *wdt = dev_get_drvdata(dev);
+	uint32_t status = readl(wdt->base + WDT_TIMEOUT_STATUS);
+
+	return sprintf(buf, "%u\n",
+			!(status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY));
+}
+
+static ssize_t access_cs0_store(struct device *dev,
+			      struct device_attribute *attr,
+			      const char *buf, size_t size)
+{
+	struct aspeed_wdt *wdt = dev_get_drvdata(dev);
+	unsigned long val;
+
+	if (kstrtoul(buf, 10, &val))
+		return -EINVAL;
+
+	if (val)
+		writel(WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION,
+			wdt->base + WDT_CLEAR_TIMEOUT_STATUS);
+
+	return size;
+}
+
+/*
+ * At alternate side the 'access_cs0' sysfs node provides:
+ *   ast2400: a way to get access to the primary SPI flash chip at CS0
+ *            after booting from the alternate chip at CS1.
+ *   ast2500: a way to restore the normal address mapping from
+ *            (CS0->CS1, CS1->CS0) to (CS0->CS0, CS1->CS1).
+ *
+ * Clearing the boot code selection and timeout counter also resets to the
+ * initial state the chip select line mapping. When the SoC is in normal
+ * mapping state (i.e. booted from CS0), clearing those bits does nothing for
+ * both versions of the SoC. For alternate boot mode (booted from CS1 due to
+ * wdt2 expiration) the behavior differs as described above.
+ *
+ * This option can be used with wdt2 (watchdog1) only.
+ */
+static DEVICE_ATTR_RW(access_cs0);
+
+static struct attribute *bswitch_attrs[] = {
+	&dev_attr_access_cs0.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(bswitch);
+
 static const struct watchdog_ops aspeed_wdt_ops = {
 	.start		= aspeed_wdt_start,
 	.stop		= aspeed_wdt_stop,
@@ -306,9 +359,16 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 	}
 
 	status = readl(wdt->base + WDT_TIMEOUT_STATUS);
-	if (status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY)
+	if (status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY) {
 		wdt->wdd.bootstatus = WDIOF_CARDRESET;
 
+		if (of_device_is_compatible(np, "aspeed,ast2400-wdt") ||
+			of_device_is_compatible(np, "aspeed,ast2500-wdt"))
+			wdt->wdd.groups = bswitch_groups;
+	}
+
+	dev_set_drvdata(dev, wdt);
+
 	return devm_watchdog_register_device(dev, &wdt->wdd);
 }
 
-- 
2.20.1


  parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-26 10:46 [PATCH v2 0/4] add dual-boot support Ivan Mikhaylov
2019-08-26 10:46 ` [PATCH v2 1/4] vesnin: add wdt2 section with alt-boot option Ivan Mikhaylov
2019-08-26 10:46 ` [PATCH v2 2/4] vesnin: add secondary SPI flash chip Ivan Mikhaylov
2019-08-26 10:46 ` Ivan Mikhaylov [this message]
2019-08-27  0:14   ` [PATCH v2 3/4] watchdog/aspeed: add support for dual boot Guenter Roeck
2019-08-27  9:24     ` Ivan Mikhaylov
2019-08-27 13:06       ` Guenter Roeck
2019-08-26 10:46 ` [PATCH v2 4/4] dt-bindings/watchdog: Add access_cs0 option for alt-boot Ivan Mikhaylov
2019-08-26 23:57   ` Andrew Jeffery
2019-08-27  0:08     ` Guenter Roeck
2019-08-27  0:11       ` Andrew Jeffery
2019-08-29 22:56   ` Rob Herring

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190826104636.19324-4-i.mikhaylov@yadro.com \
    --to=i.mikhaylov@yadro.com \
    --cc=a.amelkin@yadro.com \
    --cc=andrew@aj.id.au \
    --cc=devicetree@vger.kernel.org \
    --cc=joel@jms.id.au \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-aspeed@lists.ozlabs.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-watchdog@vger.kernel.org \
    --cc=linux@roeck-us.net \
    --cc=mark.rutland@arm.com \
    --cc=openbmc@lists.ozlabs.org \
    --cc=robh+dt@kernel.org \
    --cc=wim@linux-watchdog.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Watchdog Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-watchdog/0 linux-watchdog/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-watchdog linux-watchdog/ https://lore.kernel.org/linux-watchdog \
		linux-watchdog@vger.kernel.org
	public-inbox-index linux-watchdog

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-watchdog


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git