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authorEric Miao <eric.miao@marvell.com>2009-01-20 12:06:01 +0800
committerEric Miao <eric.miao@marvell.com>2009-03-23 10:11:31 +0800
commitbd5ce4332328c1fe473690a86b2e6a4157be038f (patch)
tree785aa105d3752b2df92b1792e799e3f39e1b0411 /arch/arm/plat-pxa
parente2bb5befd7b0ae2d045f4413a97db52340edec13 (diff)
downloadop-kernel-dev-bd5ce4332328c1fe473690a86b2e6a4157be038f.zip
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[ARM] pxa: introduce plat-pxa for PXA common code and add DMA support
1. introduce folder of 'arch/arm/plat-pxa' for common code across different PXA processor families 2. initially moved DMA code into plat-pxa 3. common code in <mach/dma.h> moved into <plat/dma.h>, new processors should implement its own <mach/dma.h>, provide the following required definitions and '#include <plat/dma.h>' in the end: - DMAC_REGS_VIRT for mapped virtual address of the DMA registers' physical I/O memory Signed-off-by: Eric Miao <eric.miao@marvell.com>
Diffstat (limited to 'arch/arm/plat-pxa')
-rw-r--r--arch/arm/plat-pxa/Kconfig3
-rw-r--r--arch/arm/plat-pxa/Makefile6
-rw-r--r--arch/arm/plat-pxa/dma.c144
-rw-r--r--arch/arm/plat-pxa/include/plat/dma.h85
4 files changed, 238 insertions, 0 deletions
diff --git a/arch/arm/plat-pxa/Kconfig b/arch/arm/plat-pxa/Kconfig
new file mode 100644
index 0000000..b158e98
--- /dev/null
+++ b/arch/arm/plat-pxa/Kconfig
@@ -0,0 +1,3 @@
+if PLAT_PXA
+
+endif
diff --git a/arch/arm/plat-pxa/Makefile b/arch/arm/plat-pxa/Makefile
new file mode 100644
index 0000000..dcc3cea
--- /dev/null
+++ b/arch/arm/plat-pxa/Makefile
@@ -0,0 +1,6 @@
+#
+# Makefile for code common across different PXA processor families
+#
+
+obj-y := dma.o
+
diff --git a/arch/arm/plat-pxa/dma.c b/arch/arm/plat-pxa/dma.c
new file mode 100644
index 0000000..70aeee4
--- /dev/null
+++ b/arch/arm/plat-pxa/dma.c
@@ -0,0 +1,144 @@
+/*
+ * linux/arch/arm/plat-pxa/dma.c
+ *
+ * PXA DMA registration and IRQ dispatching
+ *
+ * Author: Nicolas Pitre
+ * Created: Nov 15, 2001
+ * Copyright: MontaVista Software Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/errno.h>
+
+#include <asm/system.h>
+#include <asm/irq.h>
+#include <mach/hardware.h>
+#include <mach/dma.h>
+
+struct dma_channel {
+ char *name;
+ pxa_dma_prio prio;
+ void (*irq_handler)(int, void *);
+ void *data;
+};
+
+static struct dma_channel *dma_channels;
+static int num_dma_channels;
+
+int pxa_request_dma (char *name, pxa_dma_prio prio,
+ void (*irq_handler)(int, void *),
+ void *data)
+{
+ unsigned long flags;
+ int i, found = 0;
+
+ /* basic sanity checks */
+ if (!name || !irq_handler)
+ return -EINVAL;
+
+ local_irq_save(flags);
+
+ do {
+ /* 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) {
+ found = 1;
+ break;
+ }
+ }
+ /* if requested prio group is full, try a hier priority */
+ } while (!found && prio--);
+
+ if (found) {
+ DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
+ dma_channels[i].name = name;
+ dma_channels[i].irq_handler = irq_handler;
+ dma_channels[i].data = data;
+ } else {
+ printk (KERN_WARNING "No more available DMA channels for %s\n", name);
+ i = -ENODEV;
+ }
+
+ local_irq_restore(flags);
+ return i;
+}
+
+void pxa_free_dma (int dma_ch)
+{
+ unsigned long flags;
+
+ if (!dma_channels[dma_ch].name) {
+ printk (KERN_CRIT
+ "%s: trying to free channel %d which is already freed\n",
+ __func__, dma_ch);
+ return;
+ }
+
+ local_irq_save(flags);
+ DCSR(dma_ch) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
+ dma_channels[dma_ch].name = NULL;
+ local_irq_restore(flags);
+}
+
+static irqreturn_t dma_irq_handler(int irq, void *dev_id)
+{
+ int i, dint = DINT;
+
+ for (i = 0; i < num_dma_channels; i++) {
+ if (dint & (1 << i)) {
+ struct dma_channel *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;
+ }
+ }
+ }
+ return IRQ_HANDLED;
+}
+
+int __init pxa_init_dma(int irq, int num_ch)
+{
+ int i, ret;
+
+ dma_channels = kzalloc(sizeof(struct dma_channel) * num_ch, GFP_KERNEL);
+ if (dma_channels == NULL)
+ return -ENOMEM;
+
+ /* dma channel priorities on pxa2xx processors:
+ * ch 0 - 3, 16 - 19 <--> (0) DMA_PRIO_HIGH
+ * ch 4 - 7, 20 - 23 <--> (1) DMA_PRIO_MEDIUM
+ * ch 8 - 15, 24 - 31 <--> (2) DMA_PRIO_LOW
+ */
+ for (i = 0; i < num_ch; i++) {
+ DCSR(i) = 0;
+ dma_channels[i].prio = min((i & 0xf) >> 2, DMA_PRIO_LOW);
+ }
+
+ ret = request_irq(irq, dma_irq_handler, IRQF_DISABLED, "DMA", NULL);
+ if (ret) {
+ printk (KERN_CRIT "Wow! Can't register IRQ for DMA\n");
+ kfree(dma_channels);
+ return ret;
+ }
+
+ num_dma_channels = num_ch;
+ return 0;
+}
+
+EXPORT_SYMBOL(pxa_request_dma);
+EXPORT_SYMBOL(pxa_free_dma);
diff --git a/arch/arm/plat-pxa/include/plat/dma.h b/arch/arm/plat-pxa/include/plat/dma.h
new file mode 100644
index 0000000..a7b91dc
--- /dev/null
+++ b/arch/arm/plat-pxa/include/plat/dma.h
@@ -0,0 +1,85 @@
+#ifndef __PLAT_DMA_H
+#define __PLAT_DMA_H
+
+#define DMAC_REG(x) (*((volatile u32 *)(DMAC_REGS_VIRT + (x))))
+
+#define DCSR(n) DMAC_REG((n) << 2)
+#define DALGN DMAC_REG(0x00a0) /* DMA Alignment Register */
+#define DINT DMAC_REG(0x00f0) /* DMA Interrupt Register */
+#define DDADR(n) DMAC_REG(0x0200 + ((n) << 4))
+#define DSADR(n) DMAC_REG(0x0204 + ((n) << 4))
+#define DTADR(n) DMAC_REG(0x0208 + ((n) << 4))
+#define DCMD(n) DMAC_REG(0x020c + ((n) << 4))
+#define DRCMR(n) DMAC_REG((((n) < 64) ? 0x0100 : 0x1100) + \
+ (((n) & 0x3f) << 2))
+
+#define DCSR_RUN (1 << 31) /* Run Bit (read / write) */
+#define DCSR_NODESC (1 << 30) /* No-Descriptor Fetch (read / write) */
+#define DCSR_STOPIRQEN (1 << 29) /* Stop Interrupt Enable (read / write) */
+#define DCSR_REQPEND (1 << 8) /* Request Pending (read-only) */
+#define DCSR_STOPSTATE (1 << 3) /* Stop State (read-only) */
+#define DCSR_ENDINTR (1 << 2) /* End Interrupt (read / write) */
+#define DCSR_STARTINTR (1 << 1) /* Start Interrupt (read / write) */
+#define DCSR_BUSERR (1 << 0) /* Bus Error Interrupt (read / write) */
+
+#define DCSR_EORIRQEN (1 << 28) /* End of Receive Interrupt Enable (R/W) */
+#define DCSR_EORJMPEN (1 << 27) /* Jump to next descriptor on EOR */
+#define DCSR_EORSTOPEN (1 << 26) /* STOP on an EOR */
+#define DCSR_SETCMPST (1 << 25) /* Set Descriptor Compare Status */
+#define DCSR_CLRCMPST (1 << 24) /* Clear Descriptor Compare Status */
+#define DCSR_CMPST (1 << 10) /* The Descriptor Compare Status */
+#define DCSR_EORINTR (1 << 9) /* The end of Receive */
+
+#define DRCMR_MAPVLD (1 << 7) /* Map Valid (read / write) */
+#define DRCMR_CHLNUM 0x1f /* mask for Channel Number (read / write) */
+
+#define DDADR_DESCADDR 0xfffffff0 /* Address of next descriptor (mask) */
+#define DDADR_STOP (1 << 0) /* Stop (read / write) */
+
+#define DCMD_INCSRCADDR (1 << 31) /* Source Address Increment Setting. */
+#define DCMD_INCTRGADDR (1 << 30) /* Target Address Increment Setting. */
+#define DCMD_FLOWSRC (1 << 29) /* Flow Control by the source. */
+#define DCMD_FLOWTRG (1 << 28) /* Flow Control by the target. */
+#define DCMD_STARTIRQEN (1 << 22) /* Start Interrupt Enable */
+#define DCMD_ENDIRQEN (1 << 21) /* End Interrupt Enable */
+#define DCMD_ENDIAN (1 << 18) /* Device Endian-ness. */
+#define DCMD_BURST8 (1 << 16) /* 8 byte burst */
+#define DCMD_BURST16 (2 << 16) /* 16 byte burst */
+#define DCMD_BURST32 (3 << 16) /* 32 byte burst */
+#define DCMD_WIDTH1 (1 << 14) /* 1 byte width */
+#define DCMD_WIDTH2 (2 << 14) /* 2 byte width (HalfWord) */
+#define DCMD_WIDTH4 (3 << 14) /* 4 byte width (Word) */
+#define DCMD_LENGTH 0x01fff /* length mask (max = 8K - 1) */
+
+/*
+ * Descriptor structure for PXA's DMA engine
+ * Note: this structure must always be aligned to a 16-byte boundary.
+ */
+
+typedef struct pxa_dma_desc {
+ volatile u32 ddadr; /* Points to the next descriptor + flags */
+ volatile u32 dsadr; /* DSADR value for the current transfer */
+ volatile u32 dtadr; /* DTADR value for the current transfer */
+ volatile u32 dcmd; /* DCMD value for the current transfer */
+} pxa_dma_desc;
+
+typedef enum {
+ DMA_PRIO_HIGH = 0,
+ DMA_PRIO_MEDIUM = 1,
+ DMA_PRIO_LOW = 2
+} pxa_dma_prio;
+
+/*
+ * DMA registration
+ */
+
+int __init pxa_init_dma(int irq, int num_ch);
+
+int pxa_request_dma (char *name,
+ pxa_dma_prio prio,
+ void (*irq_handler)(int, void *),
+ void *data);
+
+void pxa_free_dma (int dma_ch);
+
+#endif /* __PLAT_DMA_H */
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