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[PATCH v2 0/7] MIPS: Miscellaneous fixes related to Android Mips emulator

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  [PATCH v2 0/7] MIPS: Miscellaneous fixes related to Android Mips emulator Aleksandar Markovic <aleksandar.markovic@rt-rk.com> - 2017-06-28 18:00 +0200
    [PATCH v2 6/7] tty: goldfish: Use streaming DMA for r/w operations on Ranchu platforms Aleksandar Markovic <aleksandar.markovic@rt-rk.com> - 2017-06-28 18:00 +0200
    [PATCH v2 7/7] tty: goldfish: Implement support for kernel 'earlycon' parameter Aleksandar Markovic <aleksandar.markovic@rt-rk.com> - 2017-06-28 18:00 +0200
    Re: [PATCH v2 0/7] MIPS: Miscellaneous fixes related to Android Mips  emulator Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-28 20:00 +0200

#1676872 — [PATCH v2 0/7] MIPS: Miscellaneous fixes related to Android Mips emulator

From: Aleksandar Markovic <aleksandar.markovic@imgtec.com>

v1->v2:

    - the patch on PREF usage in memcpy dropped as not needed
    - updated recipient lists using get_maintainer.pl
    - rebased to the latest kernel code

This series contains an assortment of changes necessary for proper
operation of Android emulator for Mips. However, we think that wider
kernel community may benefit from them too.

Aleksandar Markovic (1):
  MIPS: math-emu: Handle zero accumulator case in MADDF and MSUBF
    separately

Lingfeng Yang (1):
  input: goldfish: Fix multitouch event handling

Miodrag Dinic (5):
  MIPS: cmdline: Add support for 'memmap' parameter
  MIPS: build: Fix "-modd-spreg" switch usage when compiling for
    mips32r6
  MIPS: unaligned: Add DSP lwx & lhx missaligned access support
  tty: goldfish: Use streaming DMA for r/w operations on Ranchu
    platforms
  tty: goldfish: Implement support for kernel 'earlycon' parameter

 arch/mips/Makefile                       |   2 +-
 arch/mips/include/uapi/asm/inst.h        |  11 ++
 arch/mips/kernel/setup.c                 |  40 +++++++
 arch/mips/kernel/unaligned.c             | 174 ++++++++++++++++++-------------
 arch/mips/math-emu/dp_maddf.c            |   5 +-
 arch/mips/math-emu/sp_maddf.c            |   5 +-
 drivers/input/keyboard/goldfish_events.c |  33 +++++-
 drivers/tty/Kconfig                      |   3 +
 drivers/tty/goldfish.c                   | 145 ++++++++++++++++++++++++--
 9 files changed, 329 insertions(+), 89 deletions(-)

-- 
2.7.4

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#1676882 — [PATCH v2 6/7] tty: goldfish: Use streaming DMA for r/w operations on Ranchu platforms

From: Miodrag Dinic <miodrag.dinic@imgtec.com>

Implement tty r/w operations using streaming DMA.

Goldfish tty for Ranchu platforms has been modified to use
streaming DMA mappings for read/write operations. This change
eliminates the need for snooping through the TLB in QEMU using
cpu_get_phys_page_debug() which does not guarantee that it will
return the valid va -> pa mapping.

The streaming DMA mapping is implemented using dma_map_single() per
transfer, while dma_unmap_single() is used for unmapping right after
the DMA transfer.

Using DMA API is the proper way for handling r/w transfers and
makes this driver more portable, thus effectively eliminating
the need for virt_to_page() and page_to_phys() conversions.

This change does not affect the old style Goldfish tty behaviour
which is still used by the Goldfish emulator. Version register has
been added and probed to see which platform is running this driver.
Reading from the new GOLDFISH_TTY_VERSION register using the Goldfish
emulator will return 0 and driver will work with virtual addresses.
Whereas if run on Ranchu it returns 1, and thus DMA is used.

Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtech.com>
---
 drivers/tty/goldfish.c | 119 ++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 108 insertions(+), 11 deletions(-)

diff --git a/drivers/tty/goldfish.c b/drivers/tty/goldfish.c
index 996bd47..acd50fa 100644
--- a/drivers/tty/goldfish.c
+++ b/drivers/tty/goldfish.c
@@ -22,6 +22,8 @@
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/goldfish.h>
+#include <linux/mm.h>
+#include <linux/dma-mapping.h>
 
 enum {
 	GOLDFISH_TTY_PUT_CHAR       = 0x00,
@@ -32,6 +34,8 @@ enum {
 	GOLDFISH_TTY_DATA_LEN       = 0x14,
 	GOLDFISH_TTY_DATA_PTR_HIGH  = 0x18,
 
+	GOLDFISH_TTY_VERSION		= 0x20,
+
 	GOLDFISH_TTY_CMD_INT_DISABLE    = 0,
 	GOLDFISH_TTY_CMD_INT_ENABLE     = 1,
 	GOLDFISH_TTY_CMD_WRITE_BUFFER   = 2,
@@ -45,6 +49,8 @@ struct goldfish_tty {
 	u32 irq;
 	int opencount;
 	struct console console;
+	u32 version;
+	struct device *dev;
 };
 
 static DEFINE_MUTEX(goldfish_tty_lock);
@@ -53,24 +59,94 @@ static u32 goldfish_tty_line_count = 8;
 static u32 goldfish_tty_current_line_count;
 static struct goldfish_tty *goldfish_ttys;
 
-static void goldfish_tty_do_write(int line, const char *buf, unsigned count)
+static inline void do_rw_io(struct goldfish_tty *qtty,
+				unsigned long address,
+				unsigned int count,
+				int is_write)
 {
 	unsigned long irq_flags;
-	struct goldfish_tty *qtty = &goldfish_ttys[line];
 	void __iomem *base = qtty->base;
+
 	spin_lock_irqsave(&qtty->lock, irq_flags);
-	gf_write_ptr(buf, base + GOLDFISH_TTY_DATA_PTR,
+	gf_write_ptr((void *)address, base + GOLDFISH_TTY_DATA_PTR,
 				base + GOLDFISH_TTY_DATA_PTR_HIGH);
 	writel(count, base + GOLDFISH_TTY_DATA_LEN);
-	writel(GOLDFISH_TTY_CMD_WRITE_BUFFER, base + GOLDFISH_TTY_CMD);
+
+	if (is_write)
+		writel(GOLDFISH_TTY_CMD_WRITE_BUFFER, base + GOLDFISH_TTY_CMD);
+	else
+		writel(GOLDFISH_TTY_CMD_READ_BUFFER, base + GOLDFISH_TTY_CMD);
+
 	spin_unlock_irqrestore(&qtty->lock, irq_flags);
 }
 
+static inline void goldfish_tty_rw(struct goldfish_tty *qtty,
+				unsigned long addr,
+				unsigned int count,
+				int is_write)
+{
+	dma_addr_t dma_handle;
+	enum dma_data_direction dma_dir;
+
+	dma_dir = (is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
+	if (qtty->version) {
+		/*
+		 * Goldfish TTY for Ranchu platform uses
+		 * physical addresses and DMA for read/write operations
+		 */
+		unsigned long addr_end = addr + count;
+
+		while (addr < addr_end) {
+			unsigned long pg_end = (addr & PAGE_MASK) + PAGE_SIZE;
+			unsigned long next =
+					pg_end < addr_end ? pg_end : addr_end;
+			unsigned long avail = next - addr;
+
+			/*
+			 * Map the buffer's virtual address to the DMA address
+			 * so the buffer can be accessed by the device.
+			 */
+			dma_handle = dma_map_single(qtty->dev,
+						(void *)addr, avail, dma_dir);
+
+			if (dma_mapping_error(qtty->dev, dma_handle)) {
+				dev_err(qtty->dev, "tty: DMA mapping error.\n");
+				return;
+			}
+			do_rw_io(qtty, dma_handle, avail, is_write);
+
+			/*
+			 * Unmap the previously mapped region after
+			 * the completion of the read/write operation.
+			 */
+			dma_unmap_single(qtty->dev, dma_handle, avail, dma_dir);
+
+			addr += avail;
+		}
+	} else {
+		/*
+		 * Old style Goldfish TTY used on the Goldfish platform
+		 * uses virtual addresses.
+		 */
+		do_rw_io(qtty, addr, count, is_write);
+	}
+
+}
+
+static void goldfish_tty_do_write(int line, const char *buf,
+				unsigned int count)
+{
+	struct goldfish_tty *qtty = &goldfish_ttys[line];
+	unsigned long address = (unsigned long)(void *)buf;
+
+	goldfish_tty_rw(qtty, address, count, 1);
+}
+
 static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
 {
 	struct goldfish_tty *qtty = dev_id;
 	void __iomem *base = qtty->base;
-	unsigned long irq_flags;
+	unsigned long address;
 	unsigned char *buf;
 	u32 count;
 
@@ -79,12 +155,10 @@ static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
 		return IRQ_NONE;
 
 	count = tty_prepare_flip_string(&qtty->port, &buf, count);
-	spin_lock_irqsave(&qtty->lock, irq_flags);
-	gf_write_ptr(buf, base + GOLDFISH_TTY_DATA_PTR,
-				base + GOLDFISH_TTY_DATA_PTR_HIGH);
-	writel(count, base + GOLDFISH_TTY_DATA_LEN);
-	writel(GOLDFISH_TTY_CMD_READ_BUFFER, base + GOLDFISH_TTY_CMD);
-	spin_unlock_irqrestore(&qtty->lock, irq_flags);
+
+	address = (unsigned long)(void *)buf;
+	goldfish_tty_rw(qtty, address, count, 0);
+
 	tty_schedule_flip(&qtty->port);
 	return IRQ_HANDLED;
 }
@@ -271,6 +345,29 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 	qtty->port.ops = &goldfish_port_ops;
 	qtty->base = base;
 	qtty->irq = irq;
+	qtty->dev = &pdev->dev;
+
+	/* Goldfish TTY device used by the Goldfish emulator
+	 * should identify itself with 0, forcing the driver
+	 * to use virtual addresses. Goldfish TTY device
+	 * on Ranchu emulator (qemu2) returns 1 here and
+	 * driver will use physical addresses.
+	 */
+	qtty->version = readl(base + GOLDFISH_TTY_VERSION);
+
+	/* Goldfish TTY device on Ranchu emulator (qemu2)
+	 * will use DMA for read/write IO operations.
+	 */
+	if (qtty->version > 0) {
+		/* Initialize dma_mask to 32-bits.
+		 */
+		if (!pdev->dev.dma_mask)
+			pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
+		if (dma_set_mask(&pdev->dev, DMA_BIT_MASK(32))) {
+			dev_err(&pdev->dev, "No suitable DMA available.\n");
+			goto err_create_driver_failed;
+		}
+	}
 
 	writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_CMD);
 
-- 
2.7.4

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#1676883 — [PATCH v2 7/7] tty: goldfish: Implement support for kernel 'earlycon' parameter

From: Miodrag Dinic <miodrag.dinic@imgtec.com>

Add early console functionality to the Goldfish tty driver.

When 'earlycon' kernel command line parameter is used with no options,
the early console is determined by the 'stdout-path' property in device
tree's 'chosen' node. This is illustrated in the following device tree
source example:

Device tree example:

    chosen {
        stdout-path = "/goldfish_tty@1f004000";
    };

    goldfish_tty@1f004000 {
        interrupts = <0xc>;
        reg = <0x1f004000 0x0 0x1000>;
        compatible = "google,goldfish-tty", "generic,goldfish-tty";
    };

Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
---
 drivers/tty/Kconfig    |  3 +++
 drivers/tty/goldfish.c | 26 ++++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index 9510305..873e0ba 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -392,6 +392,9 @@ config PPC_EARLY_DEBUG_EHV_BC_HANDLE
 config GOLDFISH_TTY
 	tristate "Goldfish TTY Driver"
 	depends on GOLDFISH
+	select SERIAL_CORE
+	select SERIAL_CORE_CONSOLE
+	select SERIAL_EARLYCON
 	help
 	  Console and system TTY driver for the Goldfish virtual platform.
 
diff --git a/drivers/tty/goldfish.c b/drivers/tty/goldfish.c
index acd50fa..22b7ad5 100644
--- a/drivers/tty/goldfish.c
+++ b/drivers/tty/goldfish.c
@@ -1,6 +1,7 @@
 /*
  * Copyright (C) 2007 Google, Inc.
  * Copyright (C) 2012 Intel, Inc.
+ * Copyright (C) 2017 Imagination Technologies Ltd.
  *
  * This software is licensed under the terms of the GNU General Public
  * License version 2, as published by the Free Software Foundation, and
@@ -24,6 +25,7 @@
 #include <linux/goldfish.h>
 #include <linux/mm.h>
 #include <linux/dma-mapping.h>
+#include <linux/serial_core.h>
 
 enum {
 	GOLDFISH_TTY_PUT_CHAR       = 0x00,
@@ -427,6 +429,30 @@ static int goldfish_tty_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static void gf_early_console_putchar(struct uart_port *port, int ch)
+{
+	__raw_writel(ch, port->membase);
+}
+
+static void gf_early_write(struct console *con, const char *s, unsigned int n)
+{
+	struct earlycon_device *dev = con->data;
+
+	uart_console_write(&dev->port, s, n, gf_early_console_putchar);
+}
+
+static int __init gf_earlycon_setup(struct earlycon_device *device,
+					const char *opt)
+{
+	if (!device->port.membase)
+		return -ENODEV;
+
+	device->con->write = gf_early_write;
+	return 0;
+}
+
+OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup);
+
 static const struct of_device_id goldfish_tty_of_match[] = {
 	{ .compatible = "google,goldfish-tty", },
 	{},
-- 
2.7.4

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#1676990 — Re: [PATCH v2 0/7] MIPS: Miscellaneous fixes related to Android Mips emulator

On Wed, Jun 28, 2017 at 05:56:24PM +0200, Aleksandar Markovic wrote:
> From: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
> 
> v1->v2:
> 
>     - the patch on PREF usage in memcpy dropped as not needed
>     - updated recipient lists using get_maintainer.pl
>     - rebased to the latest kernel code
> 
> This series contains an assortment of changes necessary for proper
> operation of Android emulator for Mips. However, we think that wider
> kernel community may benefit from them too.

This is nice, thanks for these.

How well does these patches "work" with the recent goldfish
images/kernels that are out there?  I know the goldfish platform has
been revamped a lot recently, and I would not like to see these changes
cause things to break there :)

Also, any chance to get some google reviewers for these changes?  I
don't think you added any to the cc: list, how come?

thanks,

greg k-h

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