IXP4xx fixes

IXP4xx fixes

[Krzysztof Halasa]

Hello,

I'm attaching 3 IXP4xx fixes:

1. Fix Goramo Multilink GPIO conversion (regression in v3.13)
   This platform is not included by default and it seems it escaped
   testing when the GPIO was converted.

   I've noticed a patch fixing the same problem from Arnd Bergmann,
   however the other IXP4xx platforms now use the GPIO API and
   I think this single platform shouldn't be an exception.

2. Fix DMA masks (regression in v3.7)
   This patch makes IXP4xx conform to the DMA API. Newly created devices
   will have 32-bit DMA and coherent DMA masks (effectively 28-bit for
   PCI devices). dma_set_coherent_mask() will now really set the mask,
   not only test for its validity as it used to.

   A subsequent cosmetic patch for specific devices (e.g. built-in
   Ethernet and sync serial) setting DMA and coherent DMA masks may be
   needed, however it won't have any effect on the regression. Simply
   speaking, it's the core IXP4xx code that is broken (since the
   beginning I think), and it's where the fix must go.

3. Fix DMA-bounce code to allow sync from_device and to_device with
   bidirectional mappings.

   This is an issue on (probably) E100 Ethernet only. A known problem
   but few people ever cared. Fixed on X86 long ago.

   BTW this passes cleanly through DMA API debug. And it obviously
   works correctly.

This stuff is tested on Goramo Multilink and on Gateworks Cambria with
both on-chip and PCI DMA-able devices.
-- 
Krzysztof Halasa

[PATCH 1/3] IXP4xx: Fix Goramo Multilink GPIO conversion.

[Krzysztof Halasa]

arch/arm/mach-ixp4xx/goramo_mlr.c: In function 'set_scl':
arch/arm/mach-ixp4xx/goramo_mlr.c:82: error: implicit declaration of function 'gpio_line_set'

arch/arm/mach-ixp4xx/goramo_mlr.c: In function 'output_control':
arch/arm/mach-ixp4xx/goramo_mlr.c:111: error: implicit declaration of function 'gpio_line_config'
arch/arm/mach-ixp4xx/goramo_mlr.c:111: error: 'IXP4XX_GPIO_OUT' undeclared

arch/arm/mach-ixp4xx/goramo_mlr.c: In function 'hss_dcd_irq':
arch/arm/mach-ixp4xx/goramo_mlr.c:155: error: implicit declaration of function 'gpio_line_get'

arch/arm/mach-ixp4xx/goramo_mlr.c: In function 'gmlr_init':
arch/arm/mach-ixp4xx/goramo_mlr.c:416: error: 'IXP4XX_GPIO_OUT' undeclared
arch/arm/mach-ixp4xx/goramo_mlr.c:421: error: 'IXP4XX_GPIO_IN' undeclared

Signed-off-by: Krzysztof Ha?asa <khc@pm.waw.pl>

diff --git a/arch/arm/mach-ixp4xx/goramo_mlr.c b/arch/arm/mach-ixp4xx/goramo_mlr.c
index e54ff49..80bd9d6 100644
--- a/arch/arm/mach-ixp4xx/goramo_mlr.c
+++ b/arch/arm/mach-ixp4xx/goramo_mlr.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/delay.h>
+#include <linux/gpio.h>
 #include <linux/hdlc.h>
 #include <linux/i2c-gpio.h>
 #include <linux/io.h>
@@ -79,19 +80,19 @@ static u8 control_value;
 
 static void set_scl(u8 value)
 {
-	gpio_line_set(GPIO_SCL, !!value);
+	gpio_set_value(GPIO_SCL, !!value);
 	udelay(3);
 }
 
 static void set_sda(u8 value)
 {
-	gpio_line_set(GPIO_SDA, !!value);
+	gpio_set_value(GPIO_SDA, !!value);
 	udelay(3);
 }
 
 static void set_str(u8 value)
 {
-	gpio_line_set(GPIO_STR, !!value);
+	gpio_set_value(GPIO_STR, !!value);
 	udelay(3);
 }
 
@@ -108,8 +109,8 @@ static void output_control(void)
 {
 	int i;
 
-	gpio_line_config(GPIO_SCL, IXP4XX_GPIO_OUT);
-	gpio_line_config(GPIO_SDA, IXP4XX_GPIO_OUT);
+	gpio_direction_output(GPIO_SCL, 1);
+	gpio_direction_output(GPIO_SDA, 1);
 
 	for (i = 0; i < 8; i++) {
 		set_scl(0);
@@ -151,8 +152,8 @@ static int hss_set_clock(int port, unsigned int clock_type)
 
 static irqreturn_t hss_dcd_irq(int irq, void *pdev)
 {
-	int i, port = (irq == IXP4XX_GPIO_IRQ(GPIO_HSS1_DCD_N));
-	gpio_line_get(port ? GPIO_HSS1_DCD_N : GPIO_HSS0_DCD_N, &i);
+	int port = (irq == IXP4XX_GPIO_IRQ(GPIO_HSS1_DCD_N));
+	int i = gpio_get_value(port ? GPIO_HSS1_DCD_N : GPIO_HSS0_DCD_N);
 	set_carrier_cb_tab[port](pdev, !i);
 	return IRQ_HANDLED;
 }
@@ -168,7 +169,7 @@ static int hss_open(int port, void *pdev,
 	else
 		irq = IXP4XX_GPIO_IRQ(GPIO_HSS1_DCD_N);
 
-	gpio_line_get(port ? GPIO_HSS1_DCD_N : GPIO_HSS0_DCD_N, &i);
+	i = gpio_get_value(port ? GPIO_HSS1_DCD_N : GPIO_HSS0_DCD_N);
 	set_carrier_cb(pdev, !i);
 
 	set_carrier_cb_tab[!!port] = set_carrier_cb;
@@ -181,7 +182,7 @@ static int hss_open(int port, void *pdev,
 
 	set_control(port ? CONTROL_HSS1_DTR_N : CONTROL_HSS0_DTR_N, 0);
 	output_control();
-	gpio_line_set(port ? GPIO_HSS1_RTS_N : GPIO_HSS0_RTS_N, 0);
+	gpio_set_value(port ? GPIO_HSS1_RTS_N : GPIO_HSS0_RTS_N, 0);
 	return 0;
 }
 
@@ -193,7 +194,7 @@ static void hss_close(int port, void *pdev)
 
 	set_control(port ? CONTROL_HSS1_DTR_N : CONTROL_HSS0_DTR_N, 1);
 	output_control();
-	gpio_line_set(port ? GPIO_HSS1_RTS_N : GPIO_HSS0_RTS_N, 1);
+	gpio_set_value(port ? GPIO_HSS1_RTS_N : GPIO_HSS0_RTS_N, 1);
 }
 
 
@@ -413,13 +414,21 @@ static void __init gmlr_init(void)
 	if (hw_bits & CFG_HW_HAS_EEPROM)
 		device_tab[devices++] = &device_i2c; /* max index 6 */
 
-	gpio_line_config(GPIO_SCL, IXP4XX_GPIO_OUT);
-	gpio_line_config(GPIO_SDA, IXP4XX_GPIO_OUT);
-	gpio_line_config(GPIO_STR, IXP4XX_GPIO_OUT);
-	gpio_line_config(GPIO_HSS0_RTS_N, IXP4XX_GPIO_OUT);
-	gpio_line_config(GPIO_HSS1_RTS_N, IXP4XX_GPIO_OUT);
-	gpio_line_config(GPIO_HSS0_DCD_N, IXP4XX_GPIO_IN);
-	gpio_line_config(GPIO_HSS1_DCD_N, IXP4XX_GPIO_IN);
+	gpio_request(GPIO_SCL, "SCL/clock");
+	gpio_request(GPIO_SDA, "SDA/data");
+	gpio_request(GPIO_STR, "strobe");
+	gpio_request(GPIO_HSS0_RTS_N, "HSS0 RTS");
+	gpio_request(GPIO_HSS1_RTS_N, "HSS1 RTS");
+	gpio_request(GPIO_HSS0_DCD_N, "HSS0 DCD");
+	gpio_request(GPIO_HSS1_DCD_N, "HSS1 DCD");
+
+	gpio_direction_output(GPIO_SCL, 1);
+	gpio_direction_output(GPIO_SDA, 1);
+	gpio_direction_output(GPIO_STR, 0);
+	gpio_direction_output(GPIO_HSS0_RTS_N, 1);
+	gpio_direction_output(GPIO_HSS1_RTS_N, 1);
+	gpio_direction_input(GPIO_HSS0_DCD_N);
+	gpio_direction_input(GPIO_HSS1_DCD_N);
 	irq_set_irq_type(IXP4XX_GPIO_IRQ(GPIO_HSS0_DCD_N), IRQ_TYPE_EDGE_BOTH);
 	irq_set_irq_type(IXP4XX_GPIO_IRQ(GPIO_HSS1_DCD_N), IRQ_TYPE_EDGE_BOTH);
 

[PATCH 1/3] IXP4xx: Fix Goramo Multilink GPIO conversion.

[Linus Walleij]

On Sun, Mar 23, 2014 at 1:34 AM, Krzysztof Halasa <khc@pm.waw.pl> wrote:

> arch/arm/mach-ixp4xx/goramo_mlr.c: In function 'set_scl':
> arch/arm/mach-ixp4xx/goramo_mlr.c:82: error: implicit declaration of function 'gpio_line_set'
>
> arch/arm/mach-ixp4xx/goramo_mlr.c: In function 'output_control':
> arch/arm/mach-ixp4xx/goramo_mlr.c:111: error: implicit declaration of function 'gpio_line_config'
> arch/arm/mach-ixp4xx/goramo_mlr.c:111: error: 'IXP4XX_GPIO_OUT' undeclared
>
> arch/arm/mach-ixp4xx/goramo_mlr.c: In function 'hss_dcd_irq':
> arch/arm/mach-ixp4xx/goramo_mlr.c:155: error: implicit declaration of function 'gpio_line_get'
>
> arch/arm/mach-ixp4xx/goramo_mlr.c: In function 'gmlr_init':
> arch/arm/mach-ixp4xx/goramo_mlr.c:416: error: 'IXP4XX_GPIO_OUT' undeclared
> arch/arm/mach-ixp4xx/goramo_mlr.c:421: error: 'IXP4XX_GPIO_IN' undeclared
>
> Signed-off-by: Krzysztof Ha?asa <khc@pm.waw.pl>

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Mea culpa.

Arnd: can you apply this one patch directly for ARM SoC fixes and
Cc: stable at vger.kernel.org on this one?

Alternatively can you send this for fixes to arm at kernel.org with Cc:
stable added Krzysztof?

Yours,
Linus Walleij

[PATCH 1/3] IXP4xx: Fix Goramo Multilink GPIO conversion.

[Krzysztof Halasa]

Linus Walleij <linus.walleij@linaro.org> writes:

>> arch/arm/mach-ixp4xx/goramo_mlr.c:416: error: 'IXP4XX_GPIO_OUT' undeclared
>> arch/arm/mach-ixp4xx/goramo_mlr.c:421: error: 'IXP4XX_GPIO_IN' undeclared
>>
>> Signed-off-by: Krzysztof Ha?asa <khc@pm.waw.pl>
>
> Alternatively can you send this for fixes to arm at kernel.org with Cc:
> stable added Krzysztof?

Given the platform's specifics, I guess it's enough to just fix it in
mainline.
-- 
Krzysztof Halasa

[PATCH 1/3] IXP4xx: Fix Goramo Multilink GPIO conversion.

[Arnd Bergmann]

On Monday 24 March 2014, Linus Walleij wrote:
> On Sun, Mar 23, 2014 at 1:34 AM, Krzysztof Halasa <khc@pm.waw.pl> wrote:
> 
> > arch/arm/mach-ixp4xx/goramo_mlr.c: In function 'set_scl':
> > arch/arm/mach-ixp4xx/goramo_mlr.c:82: error: implicit declaration of function 'gpio_line_set'
> >
> > arch/arm/mach-ixp4xx/goramo_mlr.c: In function 'output_control':
> > arch/arm/mach-ixp4xx/goramo_mlr.c:111: error: implicit declaration of function 'gpio_line_config'
> > arch/arm/mach-ixp4xx/goramo_mlr.c:111: error: 'IXP4XX_GPIO_OUT' undeclared
> >
> > arch/arm/mach-ixp4xx/goramo_mlr.c: In function 'hss_dcd_irq':
> > arch/arm/mach-ixp4xx/goramo_mlr.c:155: error: implicit declaration of function 'gpio_line_get'
> >
> > arch/arm/mach-ixp4xx/goramo_mlr.c: In function 'gmlr_init':
> > arch/arm/mach-ixp4xx/goramo_mlr.c:416: error: 'IXP4XX_GPIO_OUT' undeclared
> > arch/arm/mach-ixp4xx/goramo_mlr.c:421: error: 'IXP4XX_GPIO_IN' undeclared
> >
> > Signed-off-by: Krzysztof Ha?asa <khc@pm.waw.pl>
> 
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
> 
> Mea culpa.
> 
> Arnd: can you apply this one patch directly for ARM SoC fixes and
> Cc: stable at vger.kernel.org on this one?
> 
> Alternatively can you send this for fixes to arm at kernel.org with Cc:
> stable added Krzysztof?

I reverted my earlier patch and applied this instead. Thanks a lot!

Did not add a stable tag, as suggested by Krzysztof.

	Arnd

[PATCH 2/3] IXP4xx: Fix DMA masks.

[Krzysztof Halasa]

Now, devices will have 32-bit default DMA masks (0xFFFFFFFF) as per DMA API.

Fixes:
$ ifconfig eth0 up
net eth0: coherent DMA mask is unset

$ ifconfig hdlc0 up
net hdlc0: coherent DMA mask is unset

Also fixes a cosmetic off-by-one bug which caused DMA transfers ending exactly
on the 64 MiB boundary to go through dmabounce unnecessarily.

Signed-off-by: Krzysztof Ha?asa <khc@pm.waw.pl>

diff --git a/arch/arm/mach-ixp4xx/common-pci.c b/arch/arm/mach-ixp4xx/common-pci.c
index 200970d..4977296 100644
--- a/arch/arm/mach-ixp4xx/common-pci.c
+++ b/arch/arm/mach-ixp4xx/common-pci.c
@@ -315,33 +315,6 @@ static int abort_handler(unsigned long addr, unsigned int fsr, struct pt_regs *r
 	return 0;
 }
 
-
-static int ixp4xx_needs_bounce(struct device *dev, dma_addr_t dma_addr, size_t size)
-{
-	return (dma_addr + size) >= SZ_64M;
-}
-
-/*
- * Setup DMA mask to 64MB on PCI devices. Ignore all other devices.
- */
-static int ixp4xx_pci_platform_notify(struct device *dev)
-{
-	if (dev_is_pci(dev)) {
-		*dev->dma_mask =  SZ_64M - 1;
-		dev->coherent_dma_mask = SZ_64M - 1;
-		dmabounce_register_dev(dev, 2048, 4096, ixp4xx_needs_bounce);
-	}
-	return 0;
-}
-
-static int ixp4xx_pci_platform_notify_remove(struct device *dev)
-{
-	if (dev_is_pci(dev))
-		dmabounce_unregister_dev(dev);
-
-	return 0;
-}
-
 void __init ixp4xx_pci_preinit(void)
 {
 	unsigned long cpuid = read_cpuid_id();
@@ -475,20 +448,8 @@ int ixp4xx_setup(int nr, struct pci_sys_data *sys)
 	pci_add_resource_offset(&sys->resources, &res[0], sys->io_offset);
 	pci_add_resource_offset(&sys->resources, &res[1], sys->mem_offset);
 
-	platform_notify = ixp4xx_pci_platform_notify;
-	platform_notify_remove = ixp4xx_pci_platform_notify_remove;
-
 	return 1;
 }
 
-int dma_set_coherent_mask(struct device *dev, u64 mask)
-{
-	if (mask >= SZ_64M - 1)
-		return 0;
-
-	return -EIO;
-}
-
 EXPORT_SYMBOL(ixp4xx_pci_read);
 EXPORT_SYMBOL(ixp4xx_pci_write);
-EXPORT_SYMBOL(dma_set_coherent_mask);
diff --git a/arch/arm/mach-ixp4xx/common.c b/arch/arm/mach-ixp4xx/common.c
index 6d68aed..12c71a4 100644
--- a/arch/arm/mach-ixp4xx/common.c
+++ b/arch/arm/mach-ixp4xx/common.c
@@ -30,8 +30,8 @@
 #include <linux/export.h>
 #include <linux/gpio.h>
 #include <linux/cpu.h>
+#include <linux/pci.h>
 #include <linux/sched_clock.h>
-
 #include <mach/udc.h>
 #include <mach/hardware.h>
 #include <mach/io.h>
@@ -40,7 +40,6 @@
 #include <asm/page.h>
 #include <asm/irq.h>
 #include <asm/system_misc.h>
-
 #include <asm/mach/map.h>
 #include <asm/mach/irq.h>
 #include <asm/mach/time.h>
@@ -578,6 +577,54 @@ void ixp4xx_restart(enum reboot_mode mode, const char *cmd)
 	}
 }
 
+#ifdef CONFIG_PCI
+static int ixp4xx_needs_bounce(struct device *dev, dma_addr_t dma_addr, size_t size)
+{
+	return (dma_addr + size) > SZ_64M;
+}
+
+static int ixp4xx_platform_notify_remove(struct device *dev)
+{
+	if (dev_is_pci(dev))
+		dmabounce_unregister_dev(dev);
+
+	return 0;
+}
+#endif
+
+/*
+ * Setup DMA mask to 64MB on PCI devices and 4 GB on all other things.
+ */
+static int ixp4xx_platform_notify(struct device *dev)
+{
+	dev->dma_mask = &dev->coherent_dma_mask;
+
+#ifdef CONFIG_PCI
+	if (dev_is_pci(dev)) {
+		dev->coherent_dma_mask = DMA_BIT_MASK(28); /* 64 MB */
+		dmabounce_register_dev(dev, 2048, 4096, ixp4xx_needs_bounce);
+		return 0;
+	}
+#endif
+
+	dev->coherent_dma_mask = DMA_BIT_MASK(32);
+	return 0;
+}
+
+int dma_set_coherent_mask(struct device *dev, u64 mask)
+{
+	if (dev_is_pci(dev))
+		mask &= DMA_BIT_MASK(28); /* 64 MB */
+
+	if ((mask & DMA_BIT_MASK(28)) == DMA_BIT_MASK(28)) {
+		dev->coherent_dma_mask = mask;
+		return 0;
+	}
+
+	return -EIO;		/* device wanted sub-64MB mask */
+}
+EXPORT_SYMBOL(dma_set_coherent_mask);
+
 #ifdef CONFIG_IXP4XX_INDIRECT_PCI
 /*
  * In the case of using indirect PCI, we simply return the actual PCI
@@ -600,12 +647,16 @@ static void ixp4xx_iounmap(void __iomem *addr)
 	if (!is_pci_memory((__force u32)addr))
 		__iounmap(addr);
 }
+#endif
 
 void __init ixp4xx_init_early(void)
 {
+	platform_notify = ixp4xx_platform_notify;
+#ifdef CONFIG_PCI
+	platform_notify_remove = ixp4xx_platform_notify_remove;
+#endif
+#ifdef CONFIG_IXP4XX_INDIRECT_PCI
 	arch_ioremap_caller = ixp4xx_ioremap_caller;
 	arch_iounmap = ixp4xx_iounmap;
-}
-#else
-void __init ixp4xx_init_early(void) {}
 #endif
+}

[PATCH 2/3] IXP4xx: Fix DMA masks.

[Simon Kågström]

On Sun, 23 Mar 2014 01:36:48 +0100
Krzysztof Halasa <khc@pm.waw.pl> wrote:

> Now, devices will have 32-bit default DMA masks (0xFFFFFFFF) as per DMA API.
> 
> Fixes:
> $ ifconfig eth0 up
>
> Signed-off-by: Krzysztof Ha?asa <khc@pm.waw.pl>

Tested-by: Simon Kagstrom <simon.kagstrom@netinsight.net>

> +#ifdef CONFIG_PCI
> +static int ixp4xx_needs_bounce(struct device *dev, dma_addr_t dma_addr, size_t size)
> +{
> +	return (dma_addr + size) > SZ_64M;
> +}
> +
> +static int ixp4xx_platform_notify_remove(struct device *dev)
> +{
> +	if (dev_is_pci(dev))
> +		dmabounce_unregister_dev(dev);
> +
> +	return 0;
> +}
> +#endif
> +
> +/*
> + * Setup DMA mask to 64MB on PCI devices and 4 GB on all other things.
> + */
> +static int ixp4xx_platform_notify(struct device *dev)
> +{
> +	dev->dma_mask = &dev->coherent_dma_mask;
> +
> +#ifdef CONFIG_PCI
> +	if (dev_is_pci(dev)) {
> +		dev->coherent_dma_mask = DMA_BIT_MASK(28); /* 64 MB */
> +		dmabounce_register_dev(dev, 2048, 4096, ixp4xx_needs_bounce);
> +		return 0;
> +	}
> +#endif

I would simply remove the #ifdef CONFIG_PCI statements: dev_is_pci(dev)
should return false at compile time if CONFIG_PCI is not set, and then
I'd trust the compiler to simply remove all dead code.

// Simon

[PATCH 2/3] IXP4xx: Fix DMA masks.

[Krzysztof Halasa]

Simon K?gstr?m <simon.kagstrom@netinsight.net> writes:

> I would simply remove the #ifdef CONFIG_PCI statements: dev_is_pci(dev)
> should return false at compile time if CONFIG_PCI is not set, and then
> I'd trust the compiler to simply remove all dead code.

This will be the same with these #ifdefs. I can imagine someone using
other compiler or e.g. -O0, and without the #ifdefs the link would fail
due to unavailability of DMA bouncer.
-- 
Krzysztof Halasa

[PATCH 2/3] IXP4xx: Fix DMA masks.

[Arnd Bergmann]

On Monday 24 March 2014, Simon K?gstr?m wrote:
> On Sun, 23 Mar 2014 01:36:48 +0100
> Krzysztof Halasa <khc@pm.waw.pl> wrote:
> 
> > Now, devices will have 32-bit default DMA masks (0xFFFFFFFF) as per DMA API.
> > 
> > Fixes:
> > $ ifconfig eth0 up
> >
> > Signed-off-by: Krzysztof Ha?asa <khc@pm.waw.pl>
> 
> Tested-by: Simon Kagstrom <simon.kagstrom@netinsight.net>

Reverted the earlier patch and applied this one, with your Tested-by tag.
Thanks!

	Arnd

[PATCH 3/3] ARM: Fix DMA-bounce code to allow sync from_device and to_device with bidirectional mappings.

[Krzysztof Halasa]

This is equivalent of a more generic change to lib/dma-debug.c which is
present since v2.6.33:

commit 42d53b4ff7d61487d18274ebdf1f70c1aef6f122
dma-debug: allow DMA_BIDIRECTIONAL mappings to be synced with DMA_FROM_DEVICE
and DMA_TO_DEVICE.

There is no need to perform full BIDIR sync (copying the buffers in case
of swiotlb and similar schemes) if we know that the owner (CPU or device)
hasn't altered the data.

Addresses the false-positive reported at
http://bugzilla.kernel.org/show_bug.cgi?id=14169

Signed-off-by: Krzysztof Ha?asa <khc@pm.waw.pl>

diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index 1143c4d..b4c17cf 100644
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -375,7 +375,7 @@ static int __dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
 
 	off = addr - buf->safe_dma_addr;
 
-	BUG_ON(buf->direction != dir);
+	BUG_ON(buf->direction != dir && buf->direction != DMA_BIDIRECTIONAL);
 
 	dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x off=%#lx) mapped to %p (dma=%#x)\n",
 		__func__, buf->ptr, virt_to_dma(dev, buf->ptr), off,
@@ -415,7 +415,7 @@ static int __dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
 
 	off = addr - buf->safe_dma_addr;
 
-	BUG_ON(buf->direction != dir);
+	BUG_ON(buf->direction != dir && buf->direction != DMA_BIDIRECTIONAL);
 
 	dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x off=%#lx) mapped to %p (dma=%#x)\n",
 		__func__, buf->ptr, virt_to_dma(dev, buf->ptr), off,

[PATCH 3/3] ARM: Fix DMA-bounce code to allow sync from_device and to_device with bidirectional mappings.

[Simon Kågström]

On Sun, 23 Mar 2014 01:38:41 +0100
Krzysztof Halasa <khc@pm.waw.pl> wrote:

> This is equivalent of a more generic change to lib/dma-debug.c which is
> present since v2.6.33:
> 
> commit 42d53b4ff7d61487d18274ebdf1f70c1aef6f122
> dma-debug: allow DMA_BIDIRECTIONAL mappings to be synced with DMA_FROM_DEVICE
> and DMA_TO_DEVICE.
> 
> There is no need to perform full BIDIR sync (copying the buffers in case
> of swiotlb and similar schemes) if we know that the owner (CPU or device)
> hasn't altered the data.
> 
> Addresses the false-positive reported at
> http://bugzilla.kernel.org/show_bug.cgi?id=14169
> 
> Signed-off-by: Krzysztof Ha?asa <khc@pm.waw.pl>

Tested-by: Simon Kagstrom <simon.kagstrom@netinsight.net>

(Tested with a e100 device which previously triggered this).

// Simon

[PATCH 3/3] ARM: Fix DMA-bounce code to allow sync from_device and to_device with bidirectional mappings.

[Arnd Bergmann]

On Sunday 23 March 2014, Krzysztof Halasa wrote:
> This is equivalent of a more generic change to lib/dma-debug.c which is
> present since v2.6.33:
> 
> commit 42d53b4ff7d61487d18274ebdf1f70c1aef6f122
> dma-debug: allow DMA_BIDIRECTIONAL mappings to be synced with DMA_FROM_DEVICE
> and DMA_TO_DEVICE.
> 
> There is no need to perform full BIDIR sync (copying the buffers in case
> of swiotlb and similar schemes) if we know that the owner (CPU or device)
> hasn't altered the data.
> 
> Addresses the false-positive reported at
> http://bugzilla.kernel.org/show_bug.cgi?id=14169
> 
> Signed-off-by: Krzysztof Ha?asa <khc@pm.waw.pl>

Looks good to me. Can you add it to Russell's patch tracker?

Acked-by: Arnd Bergmann <arnd@arndb.de>

	Arnd

> diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
> index 1143c4d..b4c17cf 100644
> --- a/arch/arm/common/dmabounce.c
> +++ b/arch/arm/common/dmabounce.c
> @@ -375,7 +375,7 @@ static int __dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
>  
>  	off = addr - buf->safe_dma_addr;
>  
> -	BUG_ON(buf->direction != dir);
> +	BUG_ON(buf->direction != dir && buf->direction != DMA_BIDIRECTIONAL);
>  
>  	dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x off=%#lx) mapped to %p (dma=%#x)\n",
>  		__func__, buf->ptr, virt_to_dma(dev, buf->ptr), off,
> @@ -415,7 +415,7 @@ static int __dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
>  
>  	off = addr - buf->safe_dma_addr;
>  
> -	BUG_ON(buf->direction != dir);
> +	BUG_ON(buf->direction != dir && buf->direction != DMA_BIDIRECTIONAL);
>  
>  	dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x off=%#lx) mapped to %p (dma=%#x)\n",
>  		__func__, buf->ptr, virt_to_dma(dev, buf->ptr), off,
>