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From: marek.vasut@gmail.com
To: devicetree@vger.kernel.org
Cc: Marek Vasut <marek.vasut+renesas@gmail.com>,
	Rob Herring <robh+dt@kernel.org>,
	Frank Rowand <frowand.list@gmail.com>,
	linux-renesas-soc@vger.kernel.org
Subject: [PATCH V2] of: Fix of_empty_ranges_quirk()
Date: Sat,  7 Sep 2019 18:15:37 +0200
Message-ID: <20190907161537.27258-1-marek.vasut@gmail.com> (raw)

From: Marek Vasut <marek.vasut+renesas@gmail.com>

The of_empty_ranges_quirk() returns a mix of boolean and signed integer
types, which cannot work well. Replace that with boolean only and fix
usage logic in of_translate_one() -- the check should trigger when the
ranges are NULL and the quirk is applicable on the hardware.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: linux-renesas-soc@vger.kernel.org
To: devicetree@vger.kernel.org
---
V2: - Rename of_empty_ranges_quirk() to of_missing_ranges_is_ok()
    - Move comment into the of_missing_ranges_is_ok() function
    - Make of_missing_ranges_is_ok() a bit more readable by adding
      a variable marking the quirk_state as initialized.
    - Reinstate check for !of_missing_ranges_is_ok() in of_translate_one()
---
 drivers/of/address.c | 47 ++++++++++++++++++++++++--------------------
 1 file changed, 26 insertions(+), 21 deletions(-)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index 978427a9d5e6..df82ef88823f 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -473,21 +473,42 @@ static struct of_bus *of_match_bus(struct device_node *np)
 	return NULL;
 }
 
-static int of_empty_ranges_quirk(struct device_node *np)
+static bool of_missing_ranges_is_ok(struct device_node *np)
 {
+	/*
+	 * Normally, an absence of a "ranges" property means we are
+	 * crossing a non-translatable boundary, and thus the addresses
+	 * below the current cannot be converted to CPU physical ones.
+	 * Unfortunately, while this is very clear in the spec, it's not
+	 * what Apple understood, and they do have things like /uni-n or
+	 * /ht nodes with no "ranges" property and a lot of perfectly
+	 * useable mapped devices below them. Thus we treat the absence of
+	 * "ranges" as equivalent to an empty "ranges" property which means
+	 * a 1:1 translation at that level. It's up to the caller not to try
+	 * to translate addresses that aren't supposed to be translated in
+	 * the first place. --BenH.
+	 *
+	 * As far as we know, this damage only exists on Apple machines, so
+	 * This code is only enabled on powerpc.
+	 */
+
 	if (IS_ENABLED(CONFIG_PPC)) {
 		/* To save cycles, we cache the result for global "Mac" setting */
-		static int quirk_state = -1;
+		static int quirk_state_initialized;
+		static bool quirk_state;
 
 		/* PA-SEMI sdc DT bug */
 		if (of_device_is_compatible(np, "1682m-sdc"))
 			return true;
 
 		/* Make quirk cached */
-		if (quirk_state < 0)
+		if (!quirk_state_initialized) {
+			quirk_state_initialized = 1;
 			quirk_state =
 				of_machine_is_compatible("Power Macintosh") ||
 				of_machine_is_compatible("MacRISC");
+		}
+
 		return quirk_state;
 	}
 	return false;
@@ -502,25 +523,9 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus,
 	int rone;
 	u64 offset = OF_BAD_ADDR;
 
-	/*
-	 * Normally, an absence of a "ranges" property means we are
-	 * crossing a non-translatable boundary, and thus the addresses
-	 * below the current cannot be converted to CPU physical ones.
-	 * Unfortunately, while this is very clear in the spec, it's not
-	 * what Apple understood, and they do have things like /uni-n or
-	 * /ht nodes with no "ranges" property and a lot of perfectly
-	 * useable mapped devices below them. Thus we treat the absence of
-	 * "ranges" as equivalent to an empty "ranges" property which means
-	 * a 1:1 translation at that level. It's up to the caller not to try
-	 * to translate addresses that aren't supposed to be translated in
-	 * the first place. --BenH.
-	 *
-	 * As far as we know, this damage only exists on Apple machines, so
-	 * This code is only enabled on powerpc. --gcl
-	 */
 	ranges = of_get_property(parent, rprop, &rlen);
-	if (ranges == NULL && !of_empty_ranges_quirk(parent)) {
-		pr_debug("no ranges; cannot translate\n");
+	if (ranges == NULL && !of_missing_ranges_is_ok(parent)) {
+		pr_err("no ranges; cannot translate\n");
 		return 1;
 	}
 	if (ranges == NULL || rlen == 0) {
-- 
2.23.0.rc1


             reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-07 16:15 marek.vasut [this message]
2019-09-09 17:37 ` Rob Herring
2019-09-14 16:00   ` Marek Vasut
2019-09-13 15:29 ` Rob Herring
2019-09-14 16:05   ` Marek Vasut

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