Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
601 lines
14 KiB
C
601 lines
14 KiB
C
/*
|
|
* Freescale i.MX28 APBH DMA driver
|
|
*
|
|
* Copyright (C) 2011 Wolfram Sang <w.sang@pengutronix.de>
|
|
*
|
|
* Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
|
|
* on behalf of DENX Software Engineering GmbH
|
|
*
|
|
* Based on code from LTIB:
|
|
* Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*/
|
|
|
|
#include <linux/list.h>
|
|
|
|
#include <common.h>
|
|
#include <malloc.h>
|
|
#include <errno.h>
|
|
#include <asm/mmu.h>
|
|
#include <asm/io.h>
|
|
#include <mach/clock.h>
|
|
#include <mach/imx-regs.h>
|
|
#include <mach/dma.h>
|
|
#include <mach/mxs.h>
|
|
|
|
#define HW_APBHX_CTRL0 0x000
|
|
#define BM_APBH_CTRL0_APB_BURST8_EN (1 << 29)
|
|
#define BM_APBH_CTRL0_APB_BURST_EN (1 << 28)
|
|
#define BP_APBH_CTRL0_CLKGATE_CHANNEL 8
|
|
#define BP_APBH_CTRL0_RESET_CHANNEL 16
|
|
#define HW_APBHX_CTRL1 0x010
|
|
#define BP_APBHX_CTRL1_CH_CMDCMPLT_IRQ_EN 16
|
|
#define HW_APBHX_CTRL2 0x020
|
|
#define HW_APBHX_CHANNEL_CTRL 0x030
|
|
#define BP_APBHX_CHANNEL_CTRL_RESET_CHANNEL 16
|
|
#define HW_APBH_VERSION (cpu_is_mx23() ? 0x3f0 : 0x800)
|
|
#define HW_APBX_VERSION 0x800
|
|
#define BP_APBHX_VERSION_MAJOR 24
|
|
#define HW_APBHX_CHn_NXTCMDAR(n) \
|
|
((apbh_is_old ? 0x050 : 0x110) + (n) * 0x70)
|
|
#define HW_APBHX_CHn_SEMA(n) \
|
|
((apbh_is_old ? 0x080 : 0x140) + (n) * 0x70)
|
|
#define BM_APBHX_CHn_SEMA_PHORE (0xff << 16)
|
|
#define BP_APBHX_CHn_SEMA_PHORE 16
|
|
|
|
static struct mxs_dma_chan mxs_dma_channels[MXS_MAX_DMA_CHANNELS];
|
|
static bool apbh_is_old;
|
|
|
|
/*
|
|
* Test is the DMA channel is valid channel
|
|
*/
|
|
int mxs_dma_validate_chan(int channel)
|
|
{
|
|
struct mxs_dma_chan *pchan;
|
|
|
|
if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
|
|
return -EINVAL;
|
|
|
|
pchan = mxs_dma_channels + channel;
|
|
if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Return the address of the command within a descriptor.
|
|
*/
|
|
static unsigned int mxs_dma_cmd_address(struct mxs_dma_desc *desc)
|
|
{
|
|
return desc->address + offsetof(struct mxs_dma_desc, cmd);
|
|
}
|
|
|
|
/*
|
|
* Read a DMA channel's hardware semaphore.
|
|
*
|
|
* As used by the MXS platform's DMA software, the DMA channel's hardware
|
|
* semaphore reflects the number of DMA commands the hardware will process, but
|
|
* has not yet finished. This is a volatile value read directly from hardware,
|
|
* so it must be be viewed as immediately stale.
|
|
*
|
|
* If the channel is not marked busy, or has finished processing all its
|
|
* commands, this value should be zero.
|
|
*
|
|
* See mxs_dma_append() for details on how DMA command blocks must be configured
|
|
* to maintain the expected behavior of the semaphore's value.
|
|
*/
|
|
static int mxs_dma_read_semaphore(int channel)
|
|
{
|
|
void __iomem *apbh_regs = (void *)MXS_APBH_BASE;
|
|
uint32_t tmp;
|
|
int ret;
|
|
|
|
ret = mxs_dma_validate_chan(channel);
|
|
if (ret)
|
|
return ret;
|
|
|
|
tmp = readl(apbh_regs + HW_APBHX_CHn_SEMA(channel));
|
|
|
|
tmp &= BM_APBHX_CHn_SEMA_PHORE;
|
|
tmp >>= BP_APBHX_CHn_SEMA_PHORE;
|
|
|
|
return tmp;
|
|
}
|
|
|
|
/*
|
|
* Enable a DMA channel.
|
|
*
|
|
* If the given channel has any DMA descriptors on its active list, this
|
|
* function causes the DMA hardware to begin processing them.
|
|
*
|
|
* This function marks the DMA channel as "busy," whether or not there are any
|
|
* descriptors to process.
|
|
*/
|
|
static int mxs_dma_enable(int channel)
|
|
{
|
|
void __iomem *apbh_regs = (void *)MXS_APBH_BASE;
|
|
unsigned int sem;
|
|
struct mxs_dma_chan *pchan;
|
|
struct mxs_dma_desc *pdesc;
|
|
int channel_bit, ret;
|
|
|
|
ret = mxs_dma_validate_chan(channel);
|
|
if (ret)
|
|
return ret;
|
|
|
|
pchan = mxs_dma_channels + channel;
|
|
|
|
if (pchan->pending_num == 0) {
|
|
pchan->flags |= MXS_DMA_FLAGS_BUSY;
|
|
return 0;
|
|
}
|
|
|
|
pdesc = list_first_entry(&pchan->active, struct mxs_dma_desc, node);
|
|
if (pdesc == NULL)
|
|
return -EFAULT;
|
|
|
|
if (pchan->flags & MXS_DMA_FLAGS_BUSY) {
|
|
if (!(pdesc->cmd.data & MXS_DMA_DESC_CHAIN))
|
|
return 0;
|
|
|
|
sem = mxs_dma_read_semaphore(channel);
|
|
if (sem == 0)
|
|
return 0;
|
|
|
|
if (sem == 1) {
|
|
pdesc = list_entry(pdesc->node.next,
|
|
struct mxs_dma_desc, node);
|
|
writel(mxs_dma_cmd_address(pdesc),
|
|
apbh_regs + HW_APBHX_CHn_NXTCMDAR(channel));
|
|
}
|
|
writel(pchan->pending_num,
|
|
apbh_regs + HW_APBHX_CHn_SEMA(channel));
|
|
pchan->active_num += pchan->pending_num;
|
|
pchan->pending_num = 0;
|
|
} else {
|
|
pchan->active_num += pchan->pending_num;
|
|
pchan->pending_num = 0;
|
|
writel(mxs_dma_cmd_address(pdesc),
|
|
apbh_regs + HW_APBHX_CHn_NXTCMDAR(channel));
|
|
writel(pchan->active_num,
|
|
apbh_regs + HW_APBHX_CHn_SEMA(channel));
|
|
channel_bit = channel + (apbh_is_old ? BP_APBH_CTRL0_CLKGATE_CHANNEL : 0);
|
|
writel(1 << channel_bit, apbh_regs + HW_APBHX_CTRL0 + BIT_CLR);
|
|
}
|
|
|
|
pchan->flags |= MXS_DMA_FLAGS_BUSY;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Disable a DMA channel.
|
|
*
|
|
* This function shuts down a DMA channel and marks it as "not busy." Any
|
|
* descriptors on the active list are immediately moved to the head of the
|
|
* "done" list, whether or not they have actually been processed by the
|
|
* hardware. The "ready" flags of these descriptors are NOT cleared, so they
|
|
* still appear to be active.
|
|
*
|
|
* This function immediately shuts down a DMA channel's hardware, aborting any
|
|
* I/O that may be in progress, potentially leaving I/O hardware in an undefined
|
|
* state. It is unwise to call this function if there is ANY chance the hardware
|
|
* is still processing a command.
|
|
*/
|
|
static int mxs_dma_disable(int channel)
|
|
{
|
|
struct mxs_dma_chan *pchan;
|
|
void __iomem *apbh_regs = (void *)MXS_APBH_BASE;
|
|
int channel_bit, ret;
|
|
|
|
ret = mxs_dma_validate_chan(channel);
|
|
if (ret)
|
|
return ret;
|
|
|
|
pchan = mxs_dma_channels + channel;
|
|
|
|
if (!(pchan->flags & MXS_DMA_FLAGS_BUSY))
|
|
return -EINVAL;
|
|
|
|
channel_bit = channel + (apbh_is_old ? BP_APBH_CTRL0_CLKGATE_CHANNEL : 0);
|
|
writel(1 << channel_bit, apbh_regs + HW_APBHX_CTRL0 + BIT_SET);
|
|
|
|
pchan->flags &= ~MXS_DMA_FLAGS_BUSY;
|
|
pchan->active_num = 0;
|
|
pchan->pending_num = 0;
|
|
list_splice_init(&pchan->active, &pchan->done);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Resets the DMA channel hardware.
|
|
*/
|
|
static int mxs_dma_reset(int channel)
|
|
{
|
|
void __iomem *apbh_regs = (void *)MXS_APBH_BASE;
|
|
int ret;
|
|
|
|
ret = mxs_dma_validate_chan(channel);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (apbh_is_old)
|
|
writel(1 << (channel + BP_APBH_CTRL0_RESET_CHANNEL),
|
|
apbh_regs + HW_APBHX_CTRL0 + BIT_SET);
|
|
else
|
|
writel(1 << (channel + BP_APBHX_CHANNEL_CTRL_RESET_CHANNEL),
|
|
apbh_regs + HW_APBHX_CHANNEL_CTRL + BIT_SET);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Enable or disable DMA interrupt.
|
|
*
|
|
* This function enables the given DMA channel to interrupt the CPU.
|
|
*/
|
|
static int mxs_dma_enable_irq(int channel, int enable)
|
|
{
|
|
void __iomem *apbh_regs = (void *)MXS_APBH_BASE;
|
|
int ret;
|
|
|
|
ret = mxs_dma_validate_chan(channel);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (enable)
|
|
writel(1 << (channel + BP_APBHX_CTRL1_CH_CMDCMPLT_IRQ_EN),
|
|
apbh_regs + HW_APBHX_CTRL1 + BIT_SET);
|
|
else
|
|
writel(1 << (channel + BP_APBHX_CTRL1_CH_CMDCMPLT_IRQ_EN),
|
|
apbh_regs + HW_APBHX_CTRL1 + BIT_CLR);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Clear DMA interrupt.
|
|
*
|
|
* The software that is using the DMA channel must register to receive its
|
|
* interrupts and, when they arrive, must call this function to clear them.
|
|
*/
|
|
static int mxs_dma_ack_irq(int channel)
|
|
{
|
|
void __iomem *apbh_regs = (void *)MXS_APBH_BASE;
|
|
int ret;
|
|
|
|
ret = mxs_dma_validate_chan(channel);
|
|
if (ret)
|
|
return ret;
|
|
|
|
writel(1 << channel, apbh_regs + HW_APBHX_CTRL1 + BIT_CLR);
|
|
writel(1 << channel, apbh_regs + HW_APBHX_CTRL2 + BIT_CLR);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Request to reserve a DMA channel
|
|
*/
|
|
static int mxs_dma_request(int channel)
|
|
{
|
|
struct mxs_dma_chan *pchan;
|
|
|
|
if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
|
|
return -EINVAL;
|
|
|
|
pchan = mxs_dma_channels + channel;
|
|
if ((pchan->flags & MXS_DMA_FLAGS_VALID) != MXS_DMA_FLAGS_VALID)
|
|
return -ENODEV;
|
|
|
|
if (pchan->flags & MXS_DMA_FLAGS_ALLOCATED)
|
|
return -EBUSY;
|
|
|
|
pchan->flags |= MXS_DMA_FLAGS_ALLOCATED;
|
|
pchan->active_num = 0;
|
|
pchan->pending_num = 0;
|
|
|
|
INIT_LIST_HEAD(&pchan->active);
|
|
INIT_LIST_HEAD(&pchan->done);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Release a DMA channel.
|
|
*
|
|
* This function releases a DMA channel from its current owner.
|
|
*
|
|
* The channel will NOT be released if it's marked "busy" (see
|
|
* mxs_dma_enable()).
|
|
*/
|
|
static int mxs_dma_release(int channel)
|
|
{
|
|
struct mxs_dma_chan *pchan;
|
|
int ret;
|
|
|
|
ret = mxs_dma_validate_chan(channel);
|
|
if (ret)
|
|
return ret;
|
|
|
|
pchan = mxs_dma_channels + channel;
|
|
|
|
if (pchan->flags & MXS_DMA_FLAGS_BUSY)
|
|
return -EBUSY;
|
|
|
|
pchan->dev = 0;
|
|
pchan->active_num = 0;
|
|
pchan->pending_num = 0;
|
|
pchan->flags &= ~MXS_DMA_FLAGS_ALLOCATED;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Allocate DMA descriptor
|
|
*/
|
|
struct mxs_dma_desc *mxs_dma_desc_alloc(void)
|
|
{
|
|
struct mxs_dma_desc *pdesc;
|
|
|
|
pdesc = dma_alloc_coherent(sizeof(struct mxs_dma_desc));
|
|
|
|
if (pdesc == NULL)
|
|
return NULL;
|
|
|
|
memset(pdesc, 0, sizeof(*pdesc));
|
|
pdesc->address = (dma_addr_t)pdesc;
|
|
|
|
return pdesc;
|
|
};
|
|
|
|
/*
|
|
* Free DMA descriptor
|
|
*/
|
|
void mxs_dma_desc_free(struct mxs_dma_desc *pdesc)
|
|
{
|
|
if (pdesc == NULL)
|
|
return;
|
|
|
|
free(pdesc);
|
|
}
|
|
|
|
/*
|
|
* Add a DMA descriptor to a channel.
|
|
*
|
|
* If the descriptor list for this channel is not empty, this function sets the
|
|
* CHAIN bit and the NEXTCMD_ADDR fields in the last descriptor's DMA command so
|
|
* it will chain to the new descriptor's command.
|
|
*
|
|
* Then, this function marks the new descriptor as "ready," adds it to the end
|
|
* of the active descriptor list, and increments the count of pending
|
|
* descriptors.
|
|
*
|
|
* The MXS platform DMA software imposes some rules on DMA commands to maintain
|
|
* important invariants. These rules are NOT checked, but they must be carefully
|
|
* applied by software that uses MXS DMA channels.
|
|
*
|
|
* Invariant:
|
|
* The DMA channel's hardware semaphore must reflect the number of DMA
|
|
* commands the hardware will process, but has not yet finished.
|
|
*
|
|
* Explanation:
|
|
* A DMA channel begins processing commands when its hardware semaphore is
|
|
* written with a value greater than zero, and it stops processing commands
|
|
* when the semaphore returns to zero.
|
|
*
|
|
* When a channel finishes a DMA command, it will decrement its semaphore if
|
|
* the DECREMENT_SEMAPHORE bit is set in that command's flags bits.
|
|
*
|
|
* In principle, it's not necessary for the DECREMENT_SEMAPHORE to be set,
|
|
* unless it suits the purposes of the software. For example, one could
|
|
* construct a series of five DMA commands, with the DECREMENT_SEMAPHORE
|
|
* bit set only in the last one. Then, setting the DMA channel's hardware
|
|
* semaphore to one would cause the entire series of five commands to be
|
|
* processed. However, this example would violate the invariant given above.
|
|
*
|
|
* Rule:
|
|
* ALL DMA commands MUST have the DECREMENT_SEMAPHORE bit set so that the DMA
|
|
* channel's hardware semaphore will be decremented EVERY time a command is
|
|
* processed.
|
|
*/
|
|
int mxs_dma_desc_append(int channel, struct mxs_dma_desc *pdesc)
|
|
{
|
|
struct mxs_dma_chan *pchan;
|
|
struct mxs_dma_desc *last;
|
|
int ret;
|
|
|
|
ret = mxs_dma_validate_chan(channel);
|
|
if (ret)
|
|
return ret;
|
|
|
|
pchan = mxs_dma_channels + channel;
|
|
|
|
pdesc->cmd.next = mxs_dma_cmd_address(pdesc);
|
|
pdesc->flags |= MXS_DMA_DESC_FIRST | MXS_DMA_DESC_LAST;
|
|
|
|
if (!list_empty(&pchan->active)) {
|
|
last = list_entry(pchan->active.prev, struct mxs_dma_desc,
|
|
node);
|
|
|
|
pdesc->flags &= ~MXS_DMA_DESC_FIRST;
|
|
last->flags &= ~MXS_DMA_DESC_LAST;
|
|
|
|
last->cmd.next = mxs_dma_cmd_address(pdesc);
|
|
last->cmd.data |= MXS_DMA_DESC_CHAIN;
|
|
}
|
|
pdesc->flags |= MXS_DMA_DESC_READY;
|
|
if (pdesc->flags & MXS_DMA_DESC_FIRST)
|
|
pchan->pending_num++;
|
|
list_add_tail(&pdesc->node, &pchan->active);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Clean up processed DMA descriptors.
|
|
*
|
|
* This function removes processed DMA descriptors from the "active" list. Pass
|
|
* in a non-NULL list head to get the descriptors moved to your list. Pass NULL
|
|
* to get the descriptors moved to the channel's "done" list. Descriptors on
|
|
* the "done" list can be retrieved with mxs_dma_get_finished().
|
|
*
|
|
* This function marks the DMA channel as "not busy" if no unprocessed
|
|
* descriptors remain on the "active" list.
|
|
*/
|
|
static int mxs_dma_finish(int channel, struct list_head *head)
|
|
{
|
|
int sem;
|
|
struct mxs_dma_chan *pchan;
|
|
struct list_head *p, *q;
|
|
struct mxs_dma_desc *pdesc;
|
|
int ret;
|
|
|
|
ret = mxs_dma_validate_chan(channel);
|
|
if (ret)
|
|
return ret;
|
|
|
|
pchan = mxs_dma_channels + channel;
|
|
|
|
sem = mxs_dma_read_semaphore(channel);
|
|
if (sem < 0)
|
|
return sem;
|
|
|
|
if (sem == pchan->active_num)
|
|
return 0;
|
|
|
|
list_for_each_safe(p, q, &pchan->active) {
|
|
if ((pchan->active_num) <= sem)
|
|
break;
|
|
|
|
pdesc = list_entry(p, struct mxs_dma_desc, node);
|
|
pdesc->flags &= ~MXS_DMA_DESC_READY;
|
|
|
|
if (head)
|
|
list_move_tail(p, head);
|
|
else
|
|
list_move_tail(p, &pchan->done);
|
|
|
|
if (pdesc->flags & MXS_DMA_DESC_LAST)
|
|
pchan->active_num--;
|
|
}
|
|
|
|
if (sem == 0)
|
|
pchan->flags &= ~MXS_DMA_FLAGS_BUSY;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Wait for DMA channel to complete
|
|
*/
|
|
static int mxs_dma_wait_complete(uint32_t timeout, unsigned int chan)
|
|
{
|
|
void __iomem *apbh_regs = (void *)MXS_APBH_BASE;
|
|
int ret;
|
|
|
|
ret = mxs_dma_validate_chan(chan);
|
|
if (ret)
|
|
return ret;
|
|
|
|
while (--timeout) {
|
|
if (readl(apbh_regs + HW_APBHX_CTRL1) & (1 << chan))
|
|
break;
|
|
udelay(1);
|
|
}
|
|
|
|
if (timeout == 0) {
|
|
ret = -ETIMEDOUT;
|
|
mxs_dma_reset(chan);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Execute the DMA channel
|
|
*/
|
|
int mxs_dma_go(int chan)
|
|
{
|
|
uint32_t timeout = 10000;
|
|
int ret;
|
|
|
|
LIST_HEAD(tmp_desc_list);
|
|
|
|
mxs_dma_enable_irq(chan, 1);
|
|
mxs_dma_enable(chan);
|
|
|
|
/* Wait for DMA to finish. */
|
|
ret = mxs_dma_wait_complete(timeout, chan);
|
|
|
|
/* Clear out the descriptors we just ran. */
|
|
mxs_dma_finish(chan, &tmp_desc_list);
|
|
|
|
/* Shut the DMA channel down. */
|
|
mxs_dma_ack_irq(chan);
|
|
mxs_dma_reset(chan);
|
|
mxs_dma_enable_irq(chan, 0);
|
|
mxs_dma_disable(chan);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Initialize the DMA hardware
|
|
*/
|
|
int mxs_dma_init(void)
|
|
{
|
|
void __iomem *apbh_regs = (void *)MXS_APBH_BASE;
|
|
struct mxs_dma_chan *pchan;
|
|
int ret, channel;
|
|
u32 val, reg;
|
|
|
|
ret = mxs_reset_block(apbh_regs, 0);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* HACK: Get CPUID and determine APBH version */
|
|
val = readl(0x8001c310) >> 16;
|
|
if (val == 0x2800)
|
|
reg = MXS_APBH_BASE + 0x0800;
|
|
else
|
|
reg = MXS_APBH_BASE + 0x03f0;
|
|
|
|
apbh_is_old = (readl((void *)reg) >> 24) < 3;
|
|
|
|
writel(BM_APBH_CTRL0_APB_BURST8_EN,
|
|
apbh_regs + HW_APBHX_CTRL0 + BIT_SET);
|
|
|
|
writel(BM_APBH_CTRL0_APB_BURST_EN,
|
|
apbh_regs + HW_APBHX_CTRL0 + BIT_SET);
|
|
|
|
for (channel = 0; channel < MXS_MAX_DMA_CHANNELS; channel++) {
|
|
pchan = mxs_dma_channels + channel;
|
|
pchan->flags = MXS_DMA_FLAGS_VALID;
|
|
|
|
ret = mxs_dma_request(channel);
|
|
|
|
if (ret) {
|
|
printf("MXS DMA: Can't acquire DMA channel %i\n",
|
|
channel);
|
|
|
|
goto err;
|
|
}
|
|
|
|
mxs_dma_reset(channel);
|
|
mxs_dma_ack_irq(channel);
|
|
}
|
|
|
|
return 0;
|
|
|
|
err:
|
|
while (--channel >= 0)
|
|
mxs_dma_release(channel);
|
|
return ret;
|
|
}
|