linux-kernel - [RFT PATCH v3 25/27] tty: serial: samsung_tty: Add earlycon support for Apple UARTs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20210304213902.83903-26-marcan@marcan.st>
Date:   Fri,  5 Mar 2021 06:39:00 +0900
From:   Hector Martin <marcan@...can.st>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     Hector Martin <marcan@...can.st>, Marc Zyngier <maz@...nel.org>,
        Rob Herring <robh@...nel.org>, Arnd Bergmann <arnd@...nel.org>,
        Olof Johansson <olof@...om.net>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Mark Kettenis <mark.kettenis@...all.nl>,
        Tony Lindgren <tony@...mide.com>,
        Mohamed Mediouni <mohamed.mediouni@...amail.com>,
        Stan Skowronek <stan@...ellium.com>,
        Alexander Graf <graf@...zon.com>,
        Will Deacon <will@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Mark Rutland <mark.rutland@....com>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jonathan Corbet <corbet@....net>,
        Catalin Marinas <catalin.marinas@....com>,
        Christoph Hellwig <hch@...radead.org>,
        "David S. Miller" <davem@...emloft.net>,
        devicetree@...r.kernel.org, linux-serial@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
        linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
        Arnd Bergmann <arnd@...db.de>
Subject: [RFT PATCH v3 25/27] tty: serial: samsung_tty: Add earlycon support for Apple UARTs

Earlycon support is identical to S3C2410, but Apple SoCs also need
MMIO mapped as nGnRnE. This is handled generically for normal drivers
including the normal UART path here, but earlycon uses fixmap and
runs before that scaffolding is ready.

Since this is the only case where we need this fix, it makes more
sense to do it here in the UART driver instead of introducing a
whole fdt nonposted-mmio resolver just for earlycon/fixmap.

Suggested-by: Arnd Bergmann <arnd@...db.de>
Signed-off-by: Hector Martin <marcan@...can.st>
---
 drivers/tty/serial/samsung_tty.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index 5ef37c4538ce..80df842bf4c7 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -3001,6 +3001,23 @@ OF_EARLYCON_DECLARE(s5pv210, "samsung,s5pv210-uart",
 			s5pv210_early_console_setup);
 OF_EARLYCON_DECLARE(exynos4210, "samsung,exynos4210-uart",
 			s5pv210_early_console_setup);
+
+/* Apple S5L */
+static int __init apple_s5l_early_console_setup(struct earlycon_device *device,
+						const char *opt)
+{
+	/* Close enough to S3C2410 for earlycon... */
+	device->port.private_data = &s3c2410_early_console_data;
+
+#ifdef CONFIG_ARM64
+	/* ... but we need to override the existing fixmap entry as nGnRnE */
+	__set_fixmap(FIX_EARLYCON_MEM_BASE, device->port.mapbase,
+		     __pgprot(PROT_DEVICE_nGnRnE));
+#endif
+	return samsung_early_console_setup(device, opt);
+}
+
+OF_EARLYCON_DECLARE(s5l, "apple,s5l-uart", apple_s5l_early_console_setup);
 #endif
 
 MODULE_ALIAS("platform:samsung-uart");
-- 
2.30.0