diff mbox series

[v12,2/5] tty: goldfish: introduce gf_ioread32()/gf_iowrite32()

Message ID 20220121200738.2577697-3-laurent@vivier.eu
State Superseded
Headers show
Series None | expand

Commit Message

Laurent Vivier Jan. 21, 2022, 8:07 p.m. UTC 
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: da31de35cd2f ("tty: goldfish: use __raw_writel()/__raw_readl()")
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 drivers/tty/goldfish.c   | 20 ++++++++++----------
 include/linux/goldfish.h | 15 +++++++++++----
 2 files changed, 21 insertions(+), 14 deletions(-)

Comments

Laurent Vivier Jan. 26, 2022, 5:32 p.m. UTC | #1 
Le 26/01/2022 à 14:41, Greg KH a écrit :
> On Fri, Jan 21, 2022 at 09:07:35PM +0100, Laurent Vivier wrote:
>> Revert
>> commit da31de35cd2f ("tty: goldfish: use __raw_writel()/__raw_readl()")
> 
> Why?
> 
>> and define gf_ioread32()/gf_iowrite32() to be able to use accessors
>> defined by the architecture.
> 
> What does this do?
> 
>>
>> Cc: stable@vger.kernel.org # v5.11+
>> Fixes: da31de35cd2f ("tty: goldfish: use __raw_writel()/__raw_readl()")
>> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
>> ---
>>   drivers/tty/goldfish.c   | 20 ++++++++++----------
>>   include/linux/goldfish.h | 15 +++++++++++----
>>   2 files changed, 21 insertions(+), 14 deletions(-)
...
>> -- 
>> 2.34.1
>>
> 
> This feels like a step backwards.  Why keep this level of indirection
> for no good reason?
> 

It was proposed by Arnd on my previous iteration of the series when I wanted to update goldfish-rtc 
in the same way:

https://lore.kernel.org/all/CAK8P3a1H6-sd_+FqnOq0Zhj=L51EWuW5VCcYeTENcp3+PkTC4Q@mail.gmail.com/

Keeping __raw_XXX() functions works on most of the cases except if the current CPU endianness can 
differ from the architecture one (like a ppc64le kernel (little-endian) running a ppc64 machine 
(big-endian)).

The best solution would be to update QEMU to set the device as a little-endian one, but google 
didn't merge its implemention in upstream QEMU and this would break all other OSes using goldfish 
devices on big-endian architectures.

Thanks,
Laurent
diff mbox series

Patch

diff --git a/drivers/tty/goldfish.c b/drivers/tty/goldfish.c
index 5ed19a9857ad..10c13b93ed52 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);
-	__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_interrupt(int irq, void *dev_id)
 	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 tty_port *port, struct tty_struct *tty)
 {
 	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 tty_port *port)
 {
 	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_in_buffer(struct tty_struct *tty)
 {
 	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 platform_device *pdev)
 	 * 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 platform_device *pdev)
 		}
 	}
 
-	__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 platform_device *pdev)
 #ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE
 static void gf_early_console_putchar(struct uart_port *port, int 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)
diff --git a/include/linux/goldfish.h b/include/linux/goldfish.h
index 12be1601fd84..bcc17f95b906 100644
--- 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(const dma_addr_t addr,
 				     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
 }