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linux/arch/arm/mach-omap2/dma.c
Nicholas Krause e3abe2556b ARM: OMAP2+: Remove unnessary return statement from the void function, omap2_show_dma_caps 
This removes the no longer required return statement at the end
of the void function, omap2_show_dma_cap due to no need for a
return statement due to this function always running successfully.

Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2015-06-01 15:01:51 -07:00

293 lines
8.8 KiB
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/*
* OMAP2+ DMA driver
*
* Copyright (C) 2003 - 2008 Nokia Corporation
* Author: Juha Yrjölä <juha.yrjola@nokia.com>
* DMA channel linking for 1610 by Samuel Ortiz <samuel.ortiz@nokia.com>
* Graphics DMA and LCD DMA graphics tranformations
* by Imre Deak <imre.deak@nokia.com>
* OMAP2/3 support Copyright (C) 2004-2007 Texas Instruments, Inc.
* Some functions based on earlier dma-omap.c Copyright (C) 2001 RidgeRun, Inc.
*
* Copyright (C) 2009 Texas Instruments
* Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com>
*
* Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com/
* Converted DMA library into platform driver
* - G, Manjunath Kondaiah <manjugk@ti.com>
*
* 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/err.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/of.h>
#include <linux/omap-dma.h>
#include "soc.h"
#include "omap_hwmod.h"
#include "omap_device.h"
static enum omap_reg_offsets dma_common_ch_end;
static const struct omap_dma_reg reg_map[] = {
[REVISION] = { 0x0000, 0x00, OMAP_DMA_REG_32BIT },
[GCR] = { 0x0078, 0x00, OMAP_DMA_REG_32BIT },
[IRQSTATUS_L0] = { 0x0008, 0x00, OMAP_DMA_REG_32BIT },
[IRQSTATUS_L1] = { 0x000c, 0x00, OMAP_DMA_REG_32BIT },
[IRQSTATUS_L2] = { 0x0010, 0x00, OMAP_DMA_REG_32BIT },
[IRQSTATUS_L3] = { 0x0014, 0x00, OMAP_DMA_REG_32BIT },
[IRQENABLE_L0] = { 0x0018, 0x00, OMAP_DMA_REG_32BIT },
[IRQENABLE_L1] = { 0x001c, 0x00, OMAP_DMA_REG_32BIT },
[IRQENABLE_L2] = { 0x0020, 0x00, OMAP_DMA_REG_32BIT },
[IRQENABLE_L3] = { 0x0024, 0x00, OMAP_DMA_REG_32BIT },
[SYSSTATUS] = { 0x0028, 0x00, OMAP_DMA_REG_32BIT },
[OCP_SYSCONFIG] = { 0x002c, 0x00, OMAP_DMA_REG_32BIT },
[CAPS_0] = { 0x0064, 0x00, OMAP_DMA_REG_32BIT },
[CAPS_2] = { 0x006c, 0x00, OMAP_DMA_REG_32BIT },
[CAPS_3] = { 0x0070, 0x00, OMAP_DMA_REG_32BIT },
[CAPS_4] = { 0x0074, 0x00, OMAP_DMA_REG_32BIT },
/* Common register offsets */
[CCR] = { 0x0080, 0x60, OMAP_DMA_REG_32BIT },
[CLNK_CTRL] = { 0x0084, 0x60, OMAP_DMA_REG_32BIT },
[CICR] = { 0x0088, 0x60, OMAP_DMA_REG_32BIT },
[CSR] = { 0x008c, 0x60, OMAP_DMA_REG_32BIT },
[CSDP] = { 0x0090, 0x60, OMAP_DMA_REG_32BIT },
[CEN] = { 0x0094, 0x60, OMAP_DMA_REG_32BIT },
[CFN] = { 0x0098, 0x60, OMAP_DMA_REG_32BIT },
[CSEI] = { 0x00a4, 0x60, OMAP_DMA_REG_32BIT },
[CSFI] = { 0x00a8, 0x60, OMAP_DMA_REG_32BIT },
[CDEI] = { 0x00ac, 0x60, OMAP_DMA_REG_32BIT },
[CDFI] = { 0x00b0, 0x60, OMAP_DMA_REG_32BIT },
[CSAC] = { 0x00b4, 0x60, OMAP_DMA_REG_32BIT },
[CDAC] = { 0x00b8, 0x60, OMAP_DMA_REG_32BIT },
/* Channel specific register offsets */
[CSSA] = { 0x009c, 0x60, OMAP_DMA_REG_32BIT },
[CDSA] = { 0x00a0, 0x60, OMAP_DMA_REG_32BIT },
[CCEN] = { 0x00bc, 0x60, OMAP_DMA_REG_32BIT },
[CCFN] = { 0x00c0, 0x60, OMAP_DMA_REG_32BIT },
[COLOR] = { 0x00c4, 0x60, OMAP_DMA_REG_32BIT },
/* OMAP4 specific registers */
[CDP] = { 0x00d0, 0x60, OMAP_DMA_REG_32BIT },
[CNDP] = { 0x00d4, 0x60, OMAP_DMA_REG_32BIT },
[CCDN] = { 0x00d8, 0x60, OMAP_DMA_REG_32BIT },
};
static void __iomem *dma_base;
static inline void dma_write(u32 val, int reg, int lch)
{
void __iomem *addr = dma_base;
addr += reg_map[reg].offset;
addr += reg_map[reg].stride * lch;
writel_relaxed(val, addr);
}
static inline u32 dma_read(int reg, int lch)
{
void __iomem *addr = dma_base;
addr += reg_map[reg].offset;
addr += reg_map[reg].stride * lch;
return readl_relaxed(addr);
}
static void omap2_clear_dma(int lch)
{
int i;
for (i = CSDP; i <= dma_common_ch_end; i += 1)
dma_write(0, i, lch);
}
static void omap2_show_dma_caps(void)
{
u8 revision = dma_read(REVISION, 0) & 0xff;
printk(KERN_INFO "OMAP DMA hardware revision %d.%d\n",
revision >> 4, revision & 0xf);
}
static unsigned configure_dma_errata(void)
{
unsigned errata = 0;
/*
* Errata applicable for OMAP2430ES1.0 and all omap2420
*
* I.
* Erratum ID: Not Available
* Inter Frame DMA buffering issue DMA will wrongly
* buffer elements if packing and bursting is enabled. This might
* result in data gets stalled in FIFO at the end of the block.
* Workaround: DMA channels must have BUFFERING_DISABLED bit set to
* guarantee no data will stay in the DMA FIFO in case inter frame
* buffering occurs
*
* II.
* Erratum ID: Not Available
* DMA may hang when several channels are used in parallel
* In the following configuration, DMA channel hanging can occur:
* a. Channel i, hardware synchronized, is enabled
* b. Another channel (Channel x), software synchronized, is enabled.
* c. Channel i is disabled before end of transfer
* d. Channel i is reenabled.
* e. Steps 1 to 4 are repeated a certain number of times.
* f. A third channel (Channel y), software synchronized, is enabled.
* Channel x and Channel y may hang immediately after step 'f'.
* Workaround:
* For any channel used - make sure NextLCH_ID is set to the value j.
*/
if (cpu_is_omap2420() || (cpu_is_omap2430() &&
(omap_type() == OMAP2430_REV_ES1_0))) {
SET_DMA_ERRATA(DMA_ERRATA_IFRAME_BUFFERING);
SET_DMA_ERRATA(DMA_ERRATA_PARALLEL_CHANNELS);
}
/*
* Erratum ID: i378: OMAP2+: sDMA Channel is not disabled
* after a transaction error.
* Workaround: SW should explicitely disable the channel.
*/
if (cpu_class_is_omap2())
SET_DMA_ERRATA(DMA_ERRATA_i378);
/*
* Erratum ID: i541: sDMA FIFO draining does not finish
* If sDMA channel is disabled on the fly, sDMA enters standby even
* through FIFO Drain is still in progress
* Workaround: Put sDMA in NoStandby more before a logical channel is
* disabled, then put it back to SmartStandby right after the channel
* finishes FIFO draining.
*/
if (cpu_is_omap34xx())
SET_DMA_ERRATA(DMA_ERRATA_i541);
/*
* Erratum ID: i88 : Special programming model needed to disable DMA
* before end of block.
* Workaround: software must ensure that the DMA is configured in No
* Standby mode(DMAx_OCP_SYSCONFIG.MIDLEMODE = "01")
*/
if (omap_type() == OMAP3430_REV_ES1_0)
SET_DMA_ERRATA(DMA_ERRATA_i88);
/*
* Erratum 3.2/3.3: sometimes 0 is returned if CSAC/CDAC is
* read before the DMA controller finished disabling the channel.
*/
SET_DMA_ERRATA(DMA_ERRATA_3_3);
/*
* Erratum ID: Not Available
* A bug in ROM code leaves IRQ status for channels 0 and 1 uncleared
* after secure sram context save and restore.
* Work around: Hence we need to manually clear those IRQs to avoid
* spurious interrupts. This affects only secure devices.
*/
if (cpu_is_omap34xx() && (omap_type() != OMAP2_DEVICE_TYPE_GP))
SET_DMA_ERRATA(DMA_ROMCODE_BUG);
return errata;
}
static struct omap_system_dma_plat_info dma_plat_info __initdata = {
.reg_map = reg_map,
.channel_stride = 0x60,
.show_dma_caps = omap2_show_dma_caps,
.clear_dma = omap2_clear_dma,
.dma_write = dma_write,
.dma_read = dma_read,
};
static struct platform_device_info omap_dma_dev_info = {
.name = "omap-dma-engine",
.id = -1,
.dma_mask = DMA_BIT_MASK(32),
};
/* One time initializations */
static int __init omap2_system_dma_init_dev(struct omap_hwmod *oh, void *unused)
{
struct platform_device *pdev;
struct omap_system_dma_plat_info p;
struct omap_dma_dev_attr *d;
struct resource *mem;
char *name = "omap_dma_system";
p = dma_plat_info;
p.dma_attr = (struct omap_dma_dev_attr *)oh->dev_attr;
p.errata = configure_dma_errata();
pdev = omap_device_build(name, 0, oh, &p, sizeof(p));
if (IS_ERR(pdev)) {
pr_err("%s: Can't build omap_device for %s:%s.\n",
__func__, name, oh->name);
return PTR_ERR(pdev);
}
omap_dma_dev_info.res = pdev->resource;
omap_dma_dev_info.num_res = pdev->num_resources;
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem) {
dev_err(&pdev->dev, "%s: no mem resource\n", __func__);
return -EINVAL;
}
dma_base = ioremap(mem->start, resource_size(mem));
if (!dma_base) {
dev_err(&pdev->dev, "%s: ioremap fail\n", __func__);
return -ENOMEM;
}
d = oh->dev_attr;
if (cpu_is_omap34xx() && (omap_type() != OMAP2_DEVICE_TYPE_GP))
d->dev_caps |= HS_CHANNELS_RESERVED;
if (platform_get_irq_byname(pdev, "0") < 0)
d->dev_caps |= DMA_ENGINE_HANDLE_IRQ;
/* Check the capabilities register for descriptor loading feature */
if (dma_read(CAPS_0, 0) & DMA_HAS_DESCRIPTOR_CAPS)
dma_common_ch_end = CCDN;
else
dma_common_ch_end = CCFN;
return 0;
}
static int __init omap2_system_dma_init(void)
{
struct platform_device *pdev;
int res;
res = omap_hwmod_for_each_by_class("dma",
omap2_system_dma_init_dev, NULL);
if (res)
return res;
if (of_have_populated_dt())
return res;
pdev = platform_device_register_full(&omap_dma_dev_info);
if (IS_ERR(pdev))
return PTR_ERR(pdev);
return res;
}
omap_arch_initcall(omap2_system_dma_init);
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