[PATCH v2] ARM: pxa: transition to dmaengine phase 1

From: Robert Jarzmik
Date: Sat Jun 06 2015 - 17:13:03 EST

In order to slowly transition pxa to dmaengine, the legacy code will now
rely on dmaengine to request a channel.

This implies that PXA architecture selects DMADEVICES and PXA_DMA,
which is not pretty. Yet it enables PXA drivers to be ported one by one,
with part of them using dmaengine, and the other part using the legacy
code.

Signed-off-by: Robert Jarzmik <robert.jarzmik@xxxxxxx>

---
Since v1: removed Kconfig selects
added the mmp_pdma platform devices for legacy platforms
fixed the legacy dma interrupt handler to cooperate with mmp_pdma
---
arch/arm/mach-pxa/devices.c | 37 ++++++++++++++++++++++++++++++++++++
arch/arm/mach-pxa/pxa25x.c | 1 +
arch/arm/mach-pxa/pxa27x.c | 1 +
arch/arm/mach-pxa/pxa3xx.c | 1 +
arch/arm/plat-pxa/dma.c | 22 ++++++++++-----------
arch/arm/plat-pxa/include/plat/dma.h | 15 +++++++++++++++
6 files changed, 66 insertions(+), 11 deletions(-)

diff --git a/arch/arm/mach-pxa/devices.c b/arch/arm/mach-pxa/devices.c
index 3543466..e6ce669 100644
--- a/arch/arm/mach-pxa/devices.c
+++ b/arch/arm/mach-pxa/devices.c
@@ -17,6 +17,7 @@
#include <linux/platform_data/camera-pxa.h>
#include <mach/audio.h>
#include <mach/hardware.h>
+#include <linux/platform_data/mmp_dma.h>
#include <linux/platform_data/mtd-nand-pxa3xx.h>

#include "devices.h"
@@ -1193,3 +1194,39 @@ void __init pxa2xx_set_spi_info(unsigned id, struct pxa2xx_spi_master *info)
pd->dev.platform_data = info;
platform_device_add(pd);
}
+
+static struct mmp_dma_platdata pxa_dma_pdata = {
+ .dma_channels = 0,
+};
+
+static struct resource pxa_dma_resource[] = {
+ [0] = {
+ .start = 0x40000000,
+ .end = 0x4000ffff,
+ .flags = IORESOURCE_MEM,
+ },
+ [1] = {
+ .start = IRQ_DMA,
+ .end = IRQ_DMA,
+ .flags = IORESOURCE_IRQ,
+ },
+};
+
+static u64 pxadma_dmamask = 0xffffffffUL;
+
+static struct platform_device pxa2xx_pxa_dma = {
+ .name = "pxa-dma",
+ .id = 0,
+ .dev = {
+ .dma_mask = &pxadma_dmamask,
+ .coherent_dma_mask = 0xffffffff,
+ },
+ .num_resources = ARRAY_SIZE(pxa_dma_resource),
+ .resource = pxa_dma_resource,
+};
+
+void __init pxa2xx_set_dmac_info(int nb_channels)
+{
+ pxa_dma_pdata.dma_channels = nb_channels;
+ pxa_register_device(&pxa2xx_pxa_dma, &pxa_dma_pdata);
+}
diff --git a/arch/arm/mach-pxa/pxa25x.c b/arch/arm/mach-pxa/pxa25x.c
index 23a90c6..1dc85ff 100644
--- a/arch/arm/mach-pxa/pxa25x.c
+++ b/arch/arm/mach-pxa/pxa25x.c
@@ -206,6 +206,7 @@ static int __init pxa25x_init(void)
register_syscore_ops(&pxa_irq_syscore_ops);
register_syscore_ops(&pxa2xx_mfp_syscore_ops);

+ pxa2xx_set_dmac_info(16);
pxa_register_device(&pxa25x_device_gpio, &pxa25x_gpio_info);
ret = platform_add_devices(pxa25x_devices,
ARRAY_SIZE(pxa25x_devices));
diff --git a/arch/arm/mach-pxa/pxa27x.c b/arch/arm/mach-pxa/pxa27x.c
index b5abdeb..e6aae9e 100644
--- a/arch/arm/mach-pxa/pxa27x.c
+++ b/arch/arm/mach-pxa/pxa27x.c
@@ -310,6 +310,7 @@ static int __init pxa27x_init(void)
if (!of_have_populated_dt()) {
pxa_register_device(&pxa27x_device_gpio,
&pxa27x_gpio_info);
+ pxa2xx_set_dmac_info(32);
ret = platform_add_devices(devices,
ARRAY_SIZE(devices));
}
diff --git a/arch/arm/mach-pxa/pxa3xx.c b/arch/arm/mach-pxa/pxa3xx.c
index bd4cbef..aa85ec1 100644
--- a/arch/arm/mach-pxa/pxa3xx.c
+++ b/arch/arm/mach-pxa/pxa3xx.c
@@ -431,6 +431,7 @@ static int __init pxa3xx_init(void)
if (of_have_populated_dt())
return 0;

+ pxa2xx_set_dmac_info(32);
ret = platform_add_devices(devices, ARRAY_SIZE(devices));
if (ret)
return ret;
diff --git a/arch/arm/plat-pxa/dma.c b/arch/arm/plat-pxa/dma.c
index d92f07f..de2b061 100644
--- a/arch/arm/plat-pxa/dma.c
+++ b/arch/arm/plat-pxa/dma.c
@@ -289,7 +289,8 @@ int pxa_request_dma (char *name, pxa_dma_prio prio,
/* try grabbing a DMA channel with the requested priority */
for (i = 0; i < num_dma_channels; i++) {
if ((dma_channels[i].prio == prio) &&
- !dma_channels[i].name) {
+ !dma_channels[i].name &&
+ !pxad_toggle_reserved_channel(i)) {
found = 1;
break;
}
@@ -326,13 +327,14 @@ void pxa_free_dma (int dma_ch)
local_irq_save(flags);
DCSR(dma_ch) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
dma_channels[dma_ch].name = NULL;
+ pxad_toggle_reserved_channel(dma_ch);
local_irq_restore(flags);
}
EXPORT_SYMBOL(pxa_free_dma);

static irqreturn_t dma_irq_handler(int irq, void *dev_id)
{
- int i, dint = DINT;
+ int i, dint = DINT, done = 0;
struct dma_channel *channel;

while (dint) {
@@ -341,16 +343,13 @@ static irqreturn_t dma_irq_handler(int irq, void *dev_id)
channel = &dma_channels[i];
if (channel->name && channel->irq_handler) {
channel->irq_handler(i, channel->data);
- } else {
- /*
- * IRQ for an unregistered DMA channel:
- * let's clear the interrupts and disable it.
- */
- printk (KERN_WARNING "spurious IRQ for DMA channel %d\n", i);
- DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
+ done++;
}
}
- return IRQ_HANDLED;
+ if (done)
+ return IRQ_HANDLED;
+ else
+ return IRQ_NONE;
}

int __init pxa_init_dma(int irq, int num_ch)
@@ -372,7 +371,8 @@ int __init pxa_init_dma(int irq, int num_ch)
spin_lock_init(&dma_channels[i].lock);
}

- ret = request_irq(irq, dma_irq_handler, 0, "DMA", NULL);
+ ret = request_irq(irq, dma_irq_handler, IRQF_SHARED, "DMA",
+ dma_channels);
if (ret) {
printk (KERN_CRIT "Wow! Can't register IRQ for DMA\n");
kfree(dma_channels);
diff --git a/arch/arm/plat-pxa/include/plat/dma.h b/arch/arm/plat-pxa/include/plat/dma.h
index a7b91dc..33ac1a9e 100644
--- a/arch/arm/plat-pxa/include/plat/dma.h
+++ b/arch/arm/plat-pxa/include/plat/dma.h
@@ -82,4 +82,19 @@ int pxa_request_dma (char *name,

void pxa_free_dma (int dma_ch);

+/*
+ * Cooperation with pxa_dma + dmaengine while there remains at least one pxa
+ * driver not converted to dmaengine.
+ */
+#if defined(CONFIG_PXA_DMA)
+extern int pxad_toggle_reserved_channel(int legacy_channel);
+#else
+static inline pxad_toggle_reserved_channel(int legacy_channel)
+{
+ return 0;
+}
+#endif
+
+extern void __init pxa2xx_set_dmac_info(int nb_channels);
+
#endif /* __PLAT_DMA_H */
--
2.1.4

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