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Diffstat (limited to '')
| -rw-r--r-- | arch/sh/drivers/dma/dma-g2.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/arch/sh/drivers/dma/dma-g2.c b/arch/sh/drivers/dma/dma-g2.c new file mode 100644 index 000000000..52a8ae5e3 --- /dev/null +++ b/arch/sh/drivers/dma/dma-g2.c @@ -0,0 +1,197 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * arch/sh/drivers/dma/dma-g2.c + * + * G2 bus DMA support + * + * Copyright (C) 2003 - 2006 Paul Mundt + */ +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/interrupt.h> +#include <asm/cacheflush.h> +#include <mach/sysasic.h> +#include <mach/dma.h> +#include <asm/dma.h> + +struct g2_channel { + unsigned long g2_addr; /* G2 bus address */ + unsigned long root_addr; /* Root bus (SH-4) address */ + unsigned long size; /* Size (in bytes), 32-byte aligned */ + unsigned long direction; /* Transfer direction */ + unsigned long ctrl; /* Transfer control */ + unsigned long chan_enable; /* Channel enable */ + unsigned long xfer_enable; /* Transfer enable */ + unsigned long xfer_stat; /* Transfer status */ +} __attribute__ ((aligned(32))); + +struct g2_status { + unsigned long g2_addr; + unsigned long root_addr; + unsigned long size; + unsigned long status; +} __attribute__ ((aligned(16))); + +struct g2_dma_info { + struct g2_channel channel[G2_NR_DMA_CHANNELS]; + unsigned long pad1[G2_NR_DMA_CHANNELS]; + unsigned long wait_state; + unsigned long pad2[10]; + unsigned long magic; + struct g2_status status[G2_NR_DMA_CHANNELS]; +} __attribute__ ((aligned(256))); + +static volatile struct g2_dma_info *g2_dma = (volatile struct g2_dma_info *)0xa05f7800; + +#define g2_bytes_remaining(i) \ + ((g2_dma->channel[i].size - \ + g2_dma->status[i].size) & 0x0fffffff) + +static irqreturn_t g2_dma_interrupt(int irq, void *dev_id) +{ + int i; + + for (i = 0; i < G2_NR_DMA_CHANNELS; i++) { + if (g2_dma->status[i].status & 0x20000000) { + unsigned int bytes = g2_bytes_remaining(i); + + if (likely(bytes == 0)) { + struct dma_info *info = dev_id; + struct dma_channel *chan = info->channels + i; + + wake_up(&chan->wait_queue); + + return IRQ_HANDLED; + } + } + } + + return IRQ_NONE; +} + +static int g2_enable_dma(struct dma_channel *chan) +{ + unsigned int chan_nr = chan->chan; + + g2_dma->channel[chan_nr].chan_enable = 1; + g2_dma->channel[chan_nr].xfer_enable = 1; + + return 0; +} + +static int g2_disable_dma(struct dma_channel *chan) +{ + unsigned int chan_nr = chan->chan; + + g2_dma->channel[chan_nr].chan_enable = 0; + g2_dma->channel[chan_nr].xfer_enable = 0; + + return 0; +} + +static int g2_xfer_dma(struct dma_channel *chan) +{ + unsigned int chan_nr = chan->chan; + + if (chan->sar & 31) { + printk("g2dma: unaligned source 0x%lx\n", chan->sar); + return -EINVAL; + } + + if (chan->dar & 31) { + printk("g2dma: unaligned dest 0x%lx\n", chan->dar); + return -EINVAL; + } + + /* Align the count */ + if (chan->count & 31) + chan->count = (chan->count + (32 - 1)) & ~(32 - 1); + + /* Fixup destination */ + chan->dar += 0xa0800000; + + /* Fixup direction */ + chan->mode = !chan->mode; + + flush_icache_range((unsigned long)chan->sar, chan->count); + + g2_disable_dma(chan); + + g2_dma->channel[chan_nr].g2_addr = chan->dar & 0x1fffffe0; + g2_dma->channel[chan_nr].root_addr = chan->sar & 0x1fffffe0; + g2_dma->channel[chan_nr].size = (chan->count & ~31) | 0x80000000; + g2_dma->channel[chan_nr].direction = chan->mode; + + /* + * bit 0 - ??? + * bit 1 - if set, generate a hardware event on transfer completion + * bit 2 - ??? something to do with suspend? + */ + g2_dma->channel[chan_nr].ctrl = 5; /* ?? */ + + g2_enable_dma(chan); + + /* debug cruft */ + pr_debug("count, sar, dar, mode, ctrl, chan, xfer: %ld, 0x%08lx, " + "0x%08lx, %ld, %ld, %ld, %ld\n", + g2_dma->channel[chan_nr].size, + g2_dma->channel[chan_nr].root_addr, + g2_dma->channel[chan_nr].g2_addr, + g2_dma->channel[chan_nr].direction, + g2_dma->channel[chan_nr].ctrl, + g2_dma->channel[chan_nr].chan_enable, + g2_dma->channel[chan_nr].xfer_enable); + + return 0; +} + +static int g2_get_residue(struct dma_channel *chan) +{ + return g2_bytes_remaining(chan->chan); +} + +static struct dma_ops g2_dma_ops = { + .xfer = g2_xfer_dma, + .get_residue = g2_get_residue, +}; + +static struct dma_info g2_dma_info = { + .name = "g2_dmac", + .nr_channels = 4, + .ops = &g2_dma_ops, + .flags = DMAC_CHANNELS_TEI_CAPABLE, +}; + +static int __init g2_dma_init(void) +{ + int ret; + + ret = request_irq(HW_EVENT_G2_DMA, g2_dma_interrupt, 0, + "g2 DMA handler", &g2_dma_info); + if (unlikely(ret)) + return -EINVAL; + + /* Magic */ + g2_dma->wait_state = 27; + g2_dma->magic = 0x4659404f; + + ret = register_dmac(&g2_dma_info); + if (unlikely(ret != 0)) + free_irq(HW_EVENT_G2_DMA, &g2_dma_info); + + return ret; +} + +static void __exit g2_dma_exit(void) +{ + free_irq(HW_EVENT_G2_DMA, &g2_dma_info); + unregister_dmac(&g2_dma_info); +} + +subsys_initcall(g2_dma_init); +module_exit(g2_dma_exit); + +MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); +MODULE_DESCRIPTION("G2 bus DMA driver"); +MODULE_LICENSE("GPL v2"); |