From bd5ce4332328c1fe473690a86b2e6a4157be038f Mon Sep 17 00:00:00 2001 From: Eric Miao Date: Tue, 20 Jan 2009 12:06:01 +0800 Subject: [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 moved into , new processors should implement its own , provide the following required definitions and '#include ' in the end: - DMAC_REGS_VIRT for mapped virtual address of the DMA registers' physical I/O memory Signed-off-by: Eric Miao --- arch/arm/plat-pxa/dma.c | 144 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 144 insertions(+) create mode 100644 arch/arm/plat-pxa/dma.c (limited to 'arch/arm/plat-pxa/dma.c') diff --git a/arch/arm/plat-pxa/dma.c b/arch/arm/plat-pxa/dma.c new file mode 100644 index 00000000000..70aeee407f7 --- /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 +#include +#include +#include +#include + +#include +#include +#include +#include + +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); -- cgit v1.2.3