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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Laurent Vivier <laurent@vivier.eu>,
        Geert Uytterhoeven <geert@linux-m68k.org>
Subject: [PATCH 5.18 748/879] tty: goldfish: Introduce gf_ioread32()/gf_iowrite32()
Date:   Tue,  7 Jun 2022 19:04:26 +0200
Message-Id: <20220607165024.567536376@linuxfoundation.org>
In-Reply-To: <20220607165002.659942637@linuxfoundation.org>
References: <20220607165002.659942637@linuxfoundation.org>
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From: Laurent Vivier <laurent@vivier.eu>

commit 2e2ac4a3327479f7e2744cdd88a5c823f2057bad upstream.

The goldfish TTY device was clearly defined as having little-endian
registers, but the switch to __raw_{read,write}l(() broke its driver
when running on big-endian kernels (if anyone ever tried this).

The m68k qemu implementation got this wrong, and assumed native-endian
registers.  While this is a bug in qemu, it is probably impossible to
fix that since there is no way of knowing which other operating systems
have started relying on that bug over the years.

Hence revert commit da31de35cd2f ("tty: goldfish: use
__raw_writel()/__raw_readl()", and define gf_ioread32()/gf_iowrite32()
to be able to use accessors defined by the architecture.

Cc: stable@vger.kernel.org # v5.11+
Fixes: da31de35cd2fb78f ("tty: goldfish: use __raw_writel()/__raw_readl()")
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Link: https://lore.kernel.org/r/20220406201523.243733-2-laurent@vivier.eu
[geert: Add rationale based on Arnd's comments]
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/goldfish.c   |   20 ++++++++++----------
 include/linux/goldfish.h |   15 +++++++++++----
 2 files changed, 21 insertions(+), 14 deletions(-)

--- a/drivers/tty/goldfish.c
+++ b/drivers/tty/goldfish.c
@@ -61,13 +61,13 @@ static void do_rw_io(struct goldfish_tty
 	spin_lock_irqsave(&qtty->lock, irq_flags);
 	gf_write_ptr((void *)address, base + GOLDFISH_TTY_REG_DATA_PTR,
 		     base + GOLDFISH_TTY_REG_DATA_PTR_HIGH);
-	__raw_writel(count, base + GOLDFISH_TTY_REG_DATA_LEN);
+	gf_iowrite32(count, base + GOLDFISH_TTY_REG_DATA_LEN);
 
 	if (is_write)
-		__raw_writel(GOLDFISH_TTY_CMD_WRITE_BUFFER,
+		gf_iowrite32(GOLDFISH_TTY_CMD_WRITE_BUFFER,
 		       base + GOLDFISH_TTY_REG_CMD);
 	else
-		__raw_writel(GOLDFISH_TTY_CMD_READ_BUFFER,
+		gf_iowrite32(GOLDFISH_TTY_CMD_READ_BUFFER,
 		       base + GOLDFISH_TTY_REG_CMD);
 
 	spin_unlock_irqrestore(&qtty->lock, irq_flags);
@@ -142,7 +142,7 @@ static irqreturn_t goldfish_tty_interrup
 	unsigned char *buf;
 	u32 count;
 
-	count = __raw_readl(base + GOLDFISH_TTY_REG_BYTES_READY);
+	count = gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY);
 	if (count == 0)
 		return IRQ_NONE;
 
@@ -159,7 +159,7 @@ static int goldfish_tty_activate(struct
 {
 	struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
 									port);
-	__raw_writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
+	gf_iowrite32(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
 	return 0;
 }
 
@@ -167,7 +167,7 @@ static void goldfish_tty_shutdown(struct
 {
 	struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
 									port);
-	__raw_writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
+	gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
 }
 
 static int goldfish_tty_open(struct tty_struct *tty, struct file *filp)
@@ -202,7 +202,7 @@ static unsigned int goldfish_tty_chars_i
 {
 	struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
 	void __iomem *base = qtty->base;
-	return __raw_readl(base + GOLDFISH_TTY_REG_BYTES_READY);
+	return gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY);
 }
 
 static void goldfish_tty_console_write(struct console *co, const char *b,
@@ -355,7 +355,7 @@ static int goldfish_tty_probe(struct pla
 	 * on Ranchu emulator (qemu2) returns 1 here and
 	 * driver will use physical addresses.
 	 */
-	qtty->version = __raw_readl(base + GOLDFISH_TTY_REG_VERSION);
+	qtty->version = gf_ioread32(base + GOLDFISH_TTY_REG_VERSION);
 
 	/*
 	 * Goldfish TTY device on Ranchu emulator (qemu2)
@@ -374,7 +374,7 @@ static int goldfish_tty_probe(struct pla
 		}
 	}
 
-	__raw_writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD);
+	gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD);
 
 	ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,
 			  "goldfish_tty", qtty);
@@ -436,7 +436,7 @@ static int goldfish_tty_remove(struct pl
 #ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE
 static void gf_early_console_putchar(struct uart_port *port, unsigned char ch)
 {
-	__raw_writel(ch, port->membase);
+	gf_iowrite32(ch, port->membase);
 }
 
 static void gf_early_write(struct console *con, const char *s, unsigned int n)
--- a/include/linux/goldfish.h
+++ b/include/linux/goldfish.h
@@ -8,14 +8,21 @@
 
 /* Helpers for Goldfish virtual platform */
 
+#ifndef gf_ioread32
+#define gf_ioread32 ioread32
+#endif
+#ifndef gf_iowrite32
+#define gf_iowrite32 iowrite32
+#endif
+
 static inline void gf_write_ptr(const void *ptr, void __iomem *portl,
 				void __iomem *porth)
 {
 	const unsigned long addr = (unsigned long)ptr;
 
-	__raw_writel(lower_32_bits(addr), portl);
+	gf_iowrite32(lower_32_bits(addr), portl);
 #ifdef CONFIG_64BIT
-	__raw_writel(upper_32_bits(addr), porth);
+	gf_iowrite32(upper_32_bits(addr), porth);
 #endif
 }
 
@@ -23,9 +30,9 @@ static inline void gf_write_dma_addr(con
 				     void __iomem *portl,
 				     void __iomem *porth)
 {
-	__raw_writel(lower_32_bits(addr), portl);
+	gf_iowrite32(lower_32_bits(addr), portl);
 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
-	__raw_writel(upper_32_bits(addr), porth);
+	gf_iowrite32(upper_32_bits(addr), porth);
 #endif
 }