linux-kernel - [PATCH] tty: goldfish: use __raw_writel()/__raw

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Date:   Sat, 10 Oct 2020 02:47:49 +0200
From:   Laurent Vivier <laurent@...ier.eu>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        iodrag Dinic <miodrag.dinic@...s.com>,
        Laurent Vivier <laurent@...ier.eu>
Subject: [PATCH] tty: goldfish: use __raw_writel()/__raw_readl()

gf_early_console_putchar() uses __raw_writel() but the standard driver
uses writel()/readl(). This means we can't use both on the same machine
as the device is either big-endian, little-endian or native-endian.

As android implementation defines the endianness of the device is the one
of the architecture replace all writel()/readl() by
__raw_writel()/__raw_readl()

https://android.googlesource.com/platform/external/qemu/+/refs/heads/emu-master-dev/hw/char/goldfish_tty.c#222

Signed-off-by: Laurent Vivier <laurent@...ier.eu>
---
 drivers/tty/goldfish.c   | 18 +++++++++---------
 include/linux/goldfish.h |  8 ++++----
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/tty/goldfish.c b/drivers/tty/goldfish.c
index c8c5cdfc5e19..cd23a4b05c8f 100644
--- a/drivers/tty/goldfish.c
+++ b/drivers/tty/goldfish.c
@@ -61,13 +61,13 @@ static void do_rw_io(struct goldfish_tty *qtty,
 	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);
-	writel(count, base + GOLDFISH_TTY_REG_DATA_LEN);
+	__raw_writel(count, base + GOLDFISH_TTY_REG_DATA_LEN);
 
 	if (is_write)
-		writel(GOLDFISH_TTY_CMD_WRITE_BUFFER,
+		__raw_writel(GOLDFISH_TTY_CMD_WRITE_BUFFER,
 		       base + GOLDFISH_TTY_REG_CMD);
 	else
-		writel(GOLDFISH_TTY_CMD_READ_BUFFER,
+		__raw_writel(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_interrupt(int irq, void *dev_id)
 	unsigned char *buf;
 	u32 count;
 
-	count = readl(base + GOLDFISH_TTY_REG_BYTES_READY);
+	count = __raw_readl(base + GOLDFISH_TTY_REG_BYTES_READY);
 	if (count == 0)
 		return IRQ_NONE;
 
@@ -159,7 +159,7 @@ static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)
 {
 	struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
 									port);
-	writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
+	__raw_writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
 	return 0;
 }
 
@@ -167,7 +167,7 @@ static void goldfish_tty_shutdown(struct tty_port *port)
 {
 	struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,
 									port);
-	writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD);
+	__raw_writel(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 int goldfish_tty_chars_in_buffer(struct tty_struct *tty)
 {
 	struct goldfish_tty *qtty = &goldfish_ttys[tty->index];
 	void __iomem *base = qtty->base;
-	return readl(base + GOLDFISH_TTY_REG_BYTES_READY);
+	return __raw_readl(base + GOLDFISH_TTY_REG_BYTES_READY);
 }
 
 static void goldfish_tty_console_write(struct console *co, const char *b,
@@ -357,7 +357,7 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 	 * on Ranchu emulator (qemu2) returns 1 here and
 	 * driver will use physical addresses.
 	 */
-	qtty->version = readl(base + GOLDFISH_TTY_REG_VERSION);
+	qtty->version = __raw_readl(base + GOLDFISH_TTY_REG_VERSION);
 
 	/*
 	 * Goldfish TTY device on Ranchu emulator (qemu2)
@@ -376,7 +376,7 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 		}
 	}
 
-	writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD);
+	__raw_writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD);
 
 	ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,
 			  "goldfish_tty", qtty);
diff --git a/include/linux/goldfish.h b/include/linux/goldfish.h
index 265a099cd3b8..12be1601fd84 100644
--- a/include/linux/goldfish.h
+++ b/include/linux/goldfish.h
@@ -13,9 +13,9 @@ static inline void gf_write_ptr(const void *ptr, void __iomem *portl,
 {
 	const unsigned long addr = (unsigned long)ptr;
 
-	writel(lower_32_bits(addr), portl);
+	__raw_writel(lower_32_bits(addr), portl);
 #ifdef CONFIG_64BIT
-	writel(upper_32_bits(addr), porth);
+	__raw_writel(upper_32_bits(addr), porth);
 #endif
 }
 
@@ -23,9 +23,9 @@ static inline void gf_write_dma_addr(const dma_addr_t addr,
 				     void __iomem *portl,
 				     void __iomem *porth)
 {
-	writel(lower_32_bits(addr), portl);
+	__raw_writel(lower_32_bits(addr), portl);
 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
-	writel(upper_32_bits(addr), porth);
+	__raw_writel(upper_32_bits(addr), porth);
 #endif
 }
 
-- 
2.26.2