kernel-ark/drivers/usb/musb/cppi_dma.c
Swaminathan S 565969237a usb: musb: Fix cppi_channel_abort() function to handle Tx abort correctly
This patch fixes the Tx abort/teardown logic. We now wait for the teardown
completion interrupt and acknowledge the same by setting the tx_complete
register to 0.

This change is needed to ensure that abort processing works on DM365 platform.
Without this change after completion of abort processing the system is
overwhelmed with continuous stream of abort interrupts.

This change has been tested on all CPPI3.x platforms (DM644x, DM646x, DM35x,
DM36x).

Signed-off-by: Swaminathan S <swami.iyer@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-03-02 14:53:46 -08:00

1549 lines
43 KiB
C

/*
* Copyright (C) 2005-2006 by Texas Instruments
*
* This file implements a DMA interface using TI's CPPI DMA.
* For now it's DaVinci-only, but CPPI isn't specific to DaVinci or USB.
* The TUSB6020, using VLYNQ, has CPPI that looks much like DaVinci.
*/
#include <linux/platform_device.h>
#include <linux/usb.h>
#include "musb_core.h"
#include "musb_debug.h"
#include "cppi_dma.h"
/* CPPI DMA status 7-mar-2006:
*
* - See musb_{host,gadget}.c for more info
*
* - Correct RX DMA generally forces the engine into irq-per-packet mode,
* which can easily saturate the CPU under non-mass-storage loads.
*
* NOTES 24-aug-2006 (2.6.18-rc4):
*
* - peripheral RXDMA wedged in a test with packets of length 512/512/1.
* evidently after the 1 byte packet was received and acked, the queue
* of BDs got garbaged so it wouldn't empty the fifo. (rxcsr 0x2003,
* and RX DMA0: 4 left, 80000000 8feff880, 8feff860 8feff860; 8f321401
* 004001ff 00000001 .. 8feff860) Host was just getting NAKed on tx
* of its next (512 byte) packet. IRQ issues?
*
* REVISIT: the "transfer DMA" glue between CPPI and USB fifos will
* evidently also directly update the RX and TX CSRs ... so audit all
* host and peripheral side DMA code to avoid CSR access after DMA has
* been started.
*/
/* REVISIT now we can avoid preallocating these descriptors; or
* more simply, switch to a global freelist not per-channel ones.
* Note: at full speed, 64 descriptors == 4K bulk data.
*/
#define NUM_TXCHAN_BD 64
#define NUM_RXCHAN_BD 64
static inline void cpu_drain_writebuffer(void)
{
wmb();
#ifdef CONFIG_CPU_ARM926T
/* REVISIT this "should not be needed",
* but lack of it sure seemed to hurt ...
*/
asm("mcr p15, 0, r0, c7, c10, 4 @ drain write buffer\n");
#endif
}
static inline struct cppi_descriptor *cppi_bd_alloc(struct cppi_channel *c)
{
struct cppi_descriptor *bd = c->freelist;
if (bd)
c->freelist = bd->next;
return bd;
}
static inline void
cppi_bd_free(struct cppi_channel *c, struct cppi_descriptor *bd)
{
if (!bd)
return;
bd->next = c->freelist;
c->freelist = bd;
}
/*
* Start DMA controller
*
* Initialize the DMA controller as necessary.
*/
/* zero out entire rx state RAM entry for the channel */
static void cppi_reset_rx(struct cppi_rx_stateram __iomem *rx)
{
musb_writel(&rx->rx_skipbytes, 0, 0);
musb_writel(&rx->rx_head, 0, 0);
musb_writel(&rx->rx_sop, 0, 0);
musb_writel(&rx->rx_current, 0, 0);
musb_writel(&rx->rx_buf_current, 0, 0);
musb_writel(&rx->rx_len_len, 0, 0);
musb_writel(&rx->rx_cnt_cnt, 0, 0);
}
/* zero out entire tx state RAM entry for the channel */
static void cppi_reset_tx(struct cppi_tx_stateram __iomem *tx, u32 ptr)
{
musb_writel(&tx->tx_head, 0, 0);
musb_writel(&tx->tx_buf, 0, 0);
musb_writel(&tx->tx_current, 0, 0);
musb_writel(&tx->tx_buf_current, 0, 0);
musb_writel(&tx->tx_info, 0, 0);
musb_writel(&tx->tx_rem_len, 0, 0);
/* musb_writel(&tx->tx_dummy, 0, 0); */
musb_writel(&tx->tx_complete, 0, ptr);
}
static void __init cppi_pool_init(struct cppi *cppi, struct cppi_channel *c)
{
int j;
/* initialize channel fields */
c->head = NULL;
c->tail = NULL;
c->last_processed = NULL;
c->channel.status = MUSB_DMA_STATUS_UNKNOWN;
c->controller = cppi;
c->is_rndis = 0;
c->freelist = NULL;
/* build the BD Free list for the channel */
for (j = 0; j < NUM_TXCHAN_BD + 1; j++) {
struct cppi_descriptor *bd;
dma_addr_t dma;
bd = dma_pool_alloc(cppi->pool, GFP_KERNEL, &dma);
bd->dma = dma;
cppi_bd_free(c, bd);
}
}
static int cppi_channel_abort(struct dma_channel *);
static void cppi_pool_free(struct cppi_channel *c)
{
struct cppi *cppi = c->controller;
struct cppi_descriptor *bd;
(void) cppi_channel_abort(&c->channel);
c->channel.status = MUSB_DMA_STATUS_UNKNOWN;
c->controller = NULL;
/* free all its bds */
bd = c->last_processed;
do {
if (bd)
dma_pool_free(cppi->pool, bd, bd->dma);
bd = cppi_bd_alloc(c);
} while (bd);
c->last_processed = NULL;
}
static int __init cppi_controller_start(struct dma_controller *c)
{
struct cppi *controller;
void __iomem *tibase;
int i;
controller = container_of(c, struct cppi, controller);
/* do whatever is necessary to start controller */
for (i = 0; i < ARRAY_SIZE(controller->tx); i++) {
controller->tx[i].transmit = true;
controller->tx[i].index = i;
}
for (i = 0; i < ARRAY_SIZE(controller->rx); i++) {
controller->rx[i].transmit = false;
controller->rx[i].index = i;
}
/* setup BD list on a per channel basis */
for (i = 0; i < ARRAY_SIZE(controller->tx); i++)
cppi_pool_init(controller, controller->tx + i);
for (i = 0; i < ARRAY_SIZE(controller->rx); i++)
cppi_pool_init(controller, controller->rx + i);
tibase = controller->tibase;
INIT_LIST_HEAD(&controller->tx_complete);
/* initialise tx/rx channel head pointers to zero */
for (i = 0; i < ARRAY_SIZE(controller->tx); i++) {
struct cppi_channel *tx_ch = controller->tx + i;
struct cppi_tx_stateram __iomem *tx;
INIT_LIST_HEAD(&tx_ch->tx_complete);
tx = tibase + DAVINCI_TXCPPI_STATERAM_OFFSET(i);
tx_ch->state_ram = tx;
cppi_reset_tx(tx, 0);
}
for (i = 0; i < ARRAY_SIZE(controller->rx); i++) {
struct cppi_channel *rx_ch = controller->rx + i;
struct cppi_rx_stateram __iomem *rx;
INIT_LIST_HEAD(&rx_ch->tx_complete);
rx = tibase + DAVINCI_RXCPPI_STATERAM_OFFSET(i);
rx_ch->state_ram = rx;
cppi_reset_rx(rx);
}
/* enable individual cppi channels */
musb_writel(tibase, DAVINCI_TXCPPI_INTENAB_REG,
DAVINCI_DMA_ALL_CHANNELS_ENABLE);
musb_writel(tibase, DAVINCI_RXCPPI_INTENAB_REG,
DAVINCI_DMA_ALL_CHANNELS_ENABLE);
/* enable tx/rx CPPI control */
musb_writel(tibase, DAVINCI_TXCPPI_CTRL_REG, DAVINCI_DMA_CTRL_ENABLE);
musb_writel(tibase, DAVINCI_RXCPPI_CTRL_REG, DAVINCI_DMA_CTRL_ENABLE);
/* disable RNDIS mode, also host rx RNDIS autorequest */
musb_writel(tibase, DAVINCI_RNDIS_REG, 0);
musb_writel(tibase, DAVINCI_AUTOREQ_REG, 0);
return 0;
}
/*
* Stop DMA controller
*
* De-Init the DMA controller as necessary.
*/
static int cppi_controller_stop(struct dma_controller *c)
{
struct cppi *controller;
void __iomem *tibase;
int i;
controller = container_of(c, struct cppi, controller);
tibase = controller->tibase;
/* DISABLE INDIVIDUAL CHANNEL Interrupts */
musb_writel(tibase, DAVINCI_TXCPPI_INTCLR_REG,
DAVINCI_DMA_ALL_CHANNELS_ENABLE);
musb_writel(tibase, DAVINCI_RXCPPI_INTCLR_REG,
DAVINCI_DMA_ALL_CHANNELS_ENABLE);
DBG(1, "Tearing down RX and TX Channels\n");
for (i = 0; i < ARRAY_SIZE(controller->tx); i++) {
/* FIXME restructure of txdma to use bds like rxdma */
controller->tx[i].last_processed = NULL;
cppi_pool_free(controller->tx + i);
}
for (i = 0; i < ARRAY_SIZE(controller->rx); i++)
cppi_pool_free(controller->rx + i);
/* in Tx Case proper teardown is supported. We resort to disabling
* Tx/Rx CPPI after cleanup of Tx channels. Before TX teardown is
* complete TX CPPI cannot be disabled.
*/
/*disable tx/rx cppi */
musb_writel(tibase, DAVINCI_TXCPPI_CTRL_REG, DAVINCI_DMA_CTRL_DISABLE);
musb_writel(tibase, DAVINCI_RXCPPI_CTRL_REG, DAVINCI_DMA_CTRL_DISABLE);
return 0;
}
/* While dma channel is allocated, we only want the core irqs active
* for fault reports, otherwise we'd get irqs that we don't care about.
* Except for TX irqs, where dma done != fifo empty and reusable ...
*
* NOTE: docs don't say either way, but irq masking **enables** irqs.
*
* REVISIT same issue applies to pure PIO usage too, and non-cppi dma...
*/
static inline void core_rxirq_disable(void __iomem *tibase, unsigned epnum)
{
musb_writel(tibase, DAVINCI_USB_INT_MASK_CLR_REG, 1 << (epnum + 8));
}
static inline void core_rxirq_enable(void __iomem *tibase, unsigned epnum)
{
musb_writel(tibase, DAVINCI_USB_INT_MASK_SET_REG, 1 << (epnum + 8));
}
/*
* Allocate a CPPI Channel for DMA. With CPPI, channels are bound to
* each transfer direction of a non-control endpoint, so allocating
* (and deallocating) is mostly a way to notice bad housekeeping on
* the software side. We assume the irqs are always active.
*/
static struct dma_channel *
cppi_channel_allocate(struct dma_controller *c,
struct musb_hw_ep *ep, u8 transmit)
{
struct cppi *controller;
u8 index;
struct cppi_channel *cppi_ch;
void __iomem *tibase;
controller = container_of(c, struct cppi, controller);
tibase = controller->tibase;
/* ep0 doesn't use DMA; remember cppi indices are 0..N-1 */
index = ep->epnum - 1;
/* return the corresponding CPPI Channel Handle, and
* probably disable the non-CPPI irq until we need it.
*/
if (transmit) {
if (index >= ARRAY_SIZE(controller->tx)) {
DBG(1, "no %cX%d CPPI channel\n", 'T', index);
return NULL;
}
cppi_ch = controller->tx + index;
} else {
if (index >= ARRAY_SIZE(controller->rx)) {
DBG(1, "no %cX%d CPPI channel\n", 'R', index);
return NULL;
}
cppi_ch = controller->rx + index;
core_rxirq_disable(tibase, ep->epnum);
}
/* REVISIT make this an error later once the same driver code works
* with the other DMA engine too
*/
if (cppi_ch->hw_ep)
DBG(1, "re-allocating DMA%d %cX channel %p\n",
index, transmit ? 'T' : 'R', cppi_ch);
cppi_ch->hw_ep = ep;
cppi_ch->channel.status = MUSB_DMA_STATUS_FREE;
DBG(4, "Allocate CPPI%d %cX\n", index, transmit ? 'T' : 'R');
return &cppi_ch->channel;
}
/* Release a CPPI Channel. */
static void cppi_channel_release(struct dma_channel *channel)
{
struct cppi_channel *c;
void __iomem *tibase;
/* REVISIT: for paranoia, check state and abort if needed... */
c = container_of(channel, struct cppi_channel, channel);
tibase = c->controller->tibase;
if (!c->hw_ep)
DBG(1, "releasing idle DMA channel %p\n", c);
else if (!c->transmit)
core_rxirq_enable(tibase, c->index + 1);
/* for now, leave its cppi IRQ enabled (we won't trigger it) */
c->hw_ep = NULL;
channel->status = MUSB_DMA_STATUS_UNKNOWN;
}
/* Context: controller irqlocked */
static void
cppi_dump_rx(int level, struct cppi_channel *c, const char *tag)
{
void __iomem *base = c->controller->mregs;
struct cppi_rx_stateram __iomem *rx = c->state_ram;
musb_ep_select(base, c->index + 1);
DBG(level, "RX DMA%d%s: %d left, csr %04x, "
"%08x H%08x S%08x C%08x, "
"B%08x L%08x %08x .. %08x"
"\n",
c->index, tag,
musb_readl(c->controller->tibase,
DAVINCI_RXCPPI_BUFCNT0_REG + 4 * c->index),
musb_readw(c->hw_ep->regs, MUSB_RXCSR),
musb_readl(&rx->rx_skipbytes, 0),
musb_readl(&rx->rx_head, 0),
musb_readl(&rx->rx_sop, 0),
musb_readl(&rx->rx_current, 0),
musb_readl(&rx->rx_buf_current, 0),
musb_readl(&rx->rx_len_len, 0),
musb_readl(&rx->rx_cnt_cnt, 0),
musb_readl(&rx->rx_complete, 0)
);
}
/* Context: controller irqlocked */
static void
cppi_dump_tx(int level, struct cppi_channel *c, const char *tag)
{
void __iomem *base = c->controller->mregs;
struct cppi_tx_stateram __iomem *tx = c->state_ram;
musb_ep_select(base, c->index + 1);
DBG(level, "TX DMA%d%s: csr %04x, "
"H%08x S%08x C%08x %08x, "
"F%08x L%08x .. %08x"
"\n",
c->index, tag,
musb_readw(c->hw_ep->regs, MUSB_TXCSR),
musb_readl(&tx->tx_head, 0),
musb_readl(&tx->tx_buf, 0),
musb_readl(&tx->tx_current, 0),
musb_readl(&tx->tx_buf_current, 0),
musb_readl(&tx->tx_info, 0),
musb_readl(&tx->tx_rem_len, 0),
/* dummy/unused word 6 */
musb_readl(&tx->tx_complete, 0)
);
}
/* Context: controller irqlocked */
static inline void
cppi_rndis_update(struct cppi_channel *c, int is_rx,
void __iomem *tibase, int is_rndis)
{
/* we may need to change the rndis flag for this cppi channel */
if (c->is_rndis != is_rndis) {
u32 value = musb_readl(tibase, DAVINCI_RNDIS_REG);
u32 temp = 1 << (c->index);
if (is_rx)
temp <<= 16;
if (is_rndis)
value |= temp;
else
value &= ~temp;
musb_writel(tibase, DAVINCI_RNDIS_REG, value);
c->is_rndis = is_rndis;
}
}
#ifdef CONFIG_USB_MUSB_DEBUG
static void cppi_dump_rxbd(const char *tag, struct cppi_descriptor *bd)
{
pr_debug("RXBD/%s %08x: "
"nxt %08x buf %08x off.blen %08x opt.plen %08x\n",
tag, bd->dma,
bd->hw_next, bd->hw_bufp, bd->hw_off_len,
bd->hw_options);
}
#endif
static void cppi_dump_rxq(int level, const char *tag, struct cppi_channel *rx)
{
#ifdef CONFIG_USB_MUSB_DEBUG
struct cppi_descriptor *bd;
if (!_dbg_level(level))
return;
cppi_dump_rx(level, rx, tag);
if (rx->last_processed)
cppi_dump_rxbd("last", rx->last_processed);
for (bd = rx->head; bd; bd = bd->next)
cppi_dump_rxbd("active", bd);
#endif
}
/* NOTE: DaVinci autoreq is ignored except for host side "RNDIS" mode RX;
* so we won't ever use it (see "CPPI RX Woes" below).
*/
static inline int cppi_autoreq_update(struct cppi_channel *rx,
void __iomem *tibase, int onepacket, unsigned n_bds)
{
u32 val;
#ifdef RNDIS_RX_IS_USABLE
u32 tmp;
/* assert(is_host_active(musb)) */
/* start from "AutoReq never" */
tmp = musb_readl(tibase, DAVINCI_AUTOREQ_REG);
val = tmp & ~((0x3) << (rx->index * 2));
/* HCD arranged reqpkt for packet #1. we arrange int
* for all but the last one, maybe in two segments.
*/
if (!onepacket) {
#if 0
/* use two segments, autoreq "all" then the last "never" */
val |= ((0x3) << (rx->index * 2));
n_bds--;
#else
/* one segment, autoreq "all-but-last" */
val |= ((0x1) << (rx->index * 2));
#endif
}
if (val != tmp) {
int n = 100;
/* make sure that autoreq is updated before continuing */
musb_writel(tibase, DAVINCI_AUTOREQ_REG, val);
do {
tmp = musb_readl(tibase, DAVINCI_AUTOREQ_REG);
if (tmp == val)
break;
cpu_relax();
} while (n-- > 0);
}
#endif
/* REQPKT is turned off after each segment */
if (n_bds && rx->channel.actual_len) {
void __iomem *regs = rx->hw_ep->regs;
val = musb_readw(regs, MUSB_RXCSR);
if (!(val & MUSB_RXCSR_H_REQPKT)) {
val |= MUSB_RXCSR_H_REQPKT | MUSB_RXCSR_H_WZC_BITS;
musb_writew(regs, MUSB_RXCSR, val);
/* flush writebufer */
val = musb_readw(regs, MUSB_RXCSR);
}
}
return n_bds;
}
/* Buffer enqueuing Logic:
*
* - RX builds new queues each time, to help handle routine "early
* termination" cases (faults, including errors and short reads)
* more correctly.
*
* - for now, TX reuses the same queue of BDs every time
*
* REVISIT long term, we want a normal dynamic model.
* ... the goal will be to append to the
* existing queue, processing completed "dma buffers" (segments) on the fly.
*
* Otherwise we force an IRQ latency between requests, which slows us a lot
* (especially in "transparent" dma). Unfortunately that model seems to be
* inherent in the DMA model from the Mentor code, except in the rare case
* of transfers big enough (~128+ KB) that we could append "middle" segments
* in the TX paths. (RX can't do this, see below.)
*
* That's true even in the CPPI- friendly iso case, where most urbs have
* several small segments provided in a group and where the "packet at a time"
* "transparent" DMA model is always correct, even on the RX side.
*/
/*
* CPPI TX:
* ========
* TX is a lot more reasonable than RX; it doesn't need to run in
* irq-per-packet mode very often. RNDIS mode seems to behave too
* (except how it handles the exactly-N-packets case). Building a
* txdma queue with multiple requests (urb or usb_request) looks
* like it would work ... but fault handling would need much testing.
*
* The main issue with TX mode RNDIS relates to transfer lengths that
* are an exact multiple of the packet length. It appears that there's
* a hiccup in that case (maybe the DMA completes before the ZLP gets
* written?) boiling down to not being able to rely on CPPI writing any
* terminating zero length packet before the next transfer is written.
* So that's punted to PIO; better yet, gadget drivers can avoid it.
*
* Plus, there's allegedly an undocumented constraint that rndis transfer
* length be a multiple of 64 bytes ... but the chip doesn't act that
* way, and we really don't _want_ that behavior anyway.
*
* On TX, "transparent" mode works ... although experiments have shown
* problems trying to use the SOP/EOP bits in different USB packets.
*
* REVISIT try to handle terminating zero length packets using CPPI
* instead of doing it by PIO after an IRQ. (Meanwhile, make Ethernet
* links avoid that issue by forcing them to avoid zlps.)
*/
static void
cppi_next_tx_segment(struct musb *musb, struct cppi_channel *tx)
{
unsigned maxpacket = tx->maxpacket;
dma_addr_t addr = tx->buf_dma + tx->offset;
size_t length = tx->buf_len - tx->offset;
struct cppi_descriptor *bd;
unsigned n_bds;
unsigned i;
struct cppi_tx_stateram __iomem *tx_ram = tx->state_ram;
int rndis;
/* TX can use the CPPI "rndis" mode, where we can probably fit this
* transfer in one BD and one IRQ. The only time we would NOT want
* to use it is when hardware constraints prevent it, or if we'd
* trigger the "send a ZLP?" confusion.
*/
rndis = (maxpacket & 0x3f) == 0
&& length > maxpacket
&& length < 0xffff
&& (length % maxpacket) != 0;
if (rndis) {
maxpacket = length;
n_bds = 1;
} else {
n_bds = length / maxpacket;
if (!length || (length % maxpacket))
n_bds++;
n_bds = min(n_bds, (unsigned) NUM_TXCHAN_BD);
length = min(n_bds * maxpacket, length);
}
DBG(4, "TX DMA%d, pktSz %d %s bds %d dma 0x%x len %u\n",
tx->index,
maxpacket,
rndis ? "rndis" : "transparent",
n_bds,
addr, length);
cppi_rndis_update(tx, 0, musb->ctrl_base, rndis);
/* assuming here that channel_program is called during
* transfer initiation ... current code maintains state
* for one outstanding request only (no queues, not even
* the implicit ones of an iso urb).
*/
bd = tx->freelist;
tx->head = bd;
tx->last_processed = NULL;
/* FIXME use BD pool like RX side does, and just queue
* the minimum number for this request.
*/
/* Prepare queue of BDs first, then hand it to hardware.
* All BDs except maybe the last should be of full packet
* size; for RNDIS there _is_ only that last packet.
*/
for (i = 0; i < n_bds; ) {
if (++i < n_bds && bd->next)
bd->hw_next = bd->next->dma;
else
bd->hw_next = 0;
bd->hw_bufp = tx->buf_dma + tx->offset;
/* FIXME set EOP only on the last packet,
* SOP only on the first ... avoid IRQs
*/
if ((tx->offset + maxpacket) <= tx->buf_len) {
tx->offset += maxpacket;
bd->hw_off_len = maxpacket;
bd->hw_options = CPPI_SOP_SET | CPPI_EOP_SET
| CPPI_OWN_SET | maxpacket;
} else {
/* only this one may be a partial USB Packet */
u32 partial_len;
partial_len = tx->buf_len - tx->offset;
tx->offset = tx->buf_len;
bd->hw_off_len = partial_len;
bd->hw_options = CPPI_SOP_SET | CPPI_EOP_SET
| CPPI_OWN_SET | partial_len;
if (partial_len == 0)
bd->hw_options |= CPPI_ZERO_SET;
}
DBG(5, "TXBD %p: nxt %08x buf %08x len %04x opt %08x\n",
bd, bd->hw_next, bd->hw_bufp,
bd->hw_off_len, bd->hw_options);
/* update the last BD enqueued to the list */
tx->tail = bd;
bd = bd->next;
}
/* BDs live in DMA-coherent memory, but writes might be pending */
cpu_drain_writebuffer();
/* Write to the HeadPtr in state RAM to trigger */
musb_writel(&tx_ram->tx_head, 0, (u32)tx->freelist->dma);
cppi_dump_tx(5, tx, "/S");
}
/*
* CPPI RX Woes:
* =============
* Consider a 1KB bulk RX buffer in two scenarios: (a) it's fed two 300 byte
* packets back-to-back, and (b) it's fed two 512 byte packets back-to-back.
* (Full speed transfers have similar scenarios.)
*
* The correct behavior for Linux is that (a) fills the buffer with 300 bytes,
* and the next packet goes into a buffer that's queued later; while (b) fills
* the buffer with 1024 bytes. How to do that with CPPI?
*
* - RX queues in "rndis" mode -- one single BD -- handle (a) correctly, but
* (b) loses **BADLY** because nothing (!) happens when that second packet
* fills the buffer, much less when a third one arrives. (Which makes this
* not a "true" RNDIS mode. In the RNDIS protocol short-packet termination
* is optional, and it's fine if peripherals -- not hosts! -- pad messages
* out to end-of-buffer. Standard PCI host controller DMA descriptors
* implement that mode by default ... which is no accident.)
*
* - RX queues in "transparent" mode -- two BDs with 512 bytes each -- have
* converse problems: (b) is handled right, but (a) loses badly. CPPI RX
* ignores SOP/EOP markings and processes both of those BDs; so both packets
* are loaded into the buffer (with a 212 byte gap between them), and the next
* buffer queued will NOT get its 300 bytes of data. (It seems like SOP/EOP
* are intended as outputs for RX queues, not inputs...)
*
* - A variant of "transparent" mode -- one BD at a time -- is the only way to
* reliably make both cases work, with software handling both cases correctly
* and at the significant penalty of needing an IRQ per packet. (The lack of
* I/O overlap can be slightly ameliorated by enabling double buffering.)
*
* So how to get rid of IRQ-per-packet? The transparent multi-BD case could
* be used in special cases like mass storage, which sets URB_SHORT_NOT_OK
* (or maybe its peripheral side counterpart) to flag (a) scenarios as errors
* with guaranteed driver level fault recovery and scrubbing out what's left
* of that garbaged datastream.
*
* But there seems to be no way to identify the cases where CPPI RNDIS mode
* is appropriate -- which do NOT include RNDIS host drivers, but do include
* the CDC Ethernet driver! -- and the documentation is incomplete/wrong.
* So we can't _ever_ use RX RNDIS mode ... except by using a heuristic
* that applies best on the peripheral side (and which could fail rudely).
*
* Leaving only "transparent" mode; we avoid multi-bd modes in almost all
* cases other than mass storage class. Otherwise we're correct but slow,
* since CPPI penalizes our need for a "true RNDIS" default mode.
*/
/* Heuristic, intended to kick in for ethernet/rndis peripheral ONLY
*
* IFF
* (a) peripheral mode ... since rndis peripherals could pad their
* writes to hosts, causing i/o failure; or we'd have to cope with
* a largely unknowable variety of host side protocol variants
* (b) and short reads are NOT errors ... since full reads would
* cause those same i/o failures
* (c) and read length is
* - less than 64KB (max per cppi descriptor)
* - not a multiple of 4096 (g_zero default, full reads typical)
* - N (>1) packets long, ditto (full reads not EXPECTED)
* THEN
* try rx rndis mode
*
* Cost of heuristic failing: RXDMA wedges at the end of transfers that
* fill out the whole buffer. Buggy host side usb network drivers could
* trigger that, but "in the field" such bugs seem to be all but unknown.
*
* So this module parameter lets the heuristic be disabled. When using
* gadgetfs, the heuristic will probably need to be disabled.
*/
static int cppi_rx_rndis = 1;
module_param(cppi_rx_rndis, bool, 0);
MODULE_PARM_DESC(cppi_rx_rndis, "enable/disable RX RNDIS heuristic");
/**
* cppi_next_rx_segment - dma read for the next chunk of a buffer
* @musb: the controller
* @rx: dma channel
* @onepacket: true unless caller treats short reads as errors, and
* performs fault recovery above usbcore.
* Context: controller irqlocked
*
* See above notes about why we can't use multi-BD RX queues except in
* rare cases (mass storage class), and can never use the hardware "rndis"
* mode (since it's not a "true" RNDIS mode) with complete safety..
*
* It's ESSENTIAL that callers specify "onepacket" mode unless they kick in
* code to recover from corrupted datastreams after each short transfer.
*/
static void
cppi_next_rx_segment(struct musb *musb, struct cppi_channel *rx, int onepacket)
{
unsigned maxpacket = rx->maxpacket;
dma_addr_t addr = rx->buf_dma + rx->offset;
size_t length = rx->buf_len - rx->offset;
struct cppi_descriptor *bd, *tail;
unsigned n_bds;
unsigned i;
void __iomem *tibase = musb->ctrl_base;
int is_rndis = 0;
struct cppi_rx_stateram __iomem *rx_ram = rx->state_ram;
if (onepacket) {
/* almost every USB driver, host or peripheral side */
n_bds = 1;
/* maybe apply the heuristic above */
if (cppi_rx_rndis
&& is_peripheral_active(musb)
&& length > maxpacket
&& (length & ~0xffff) == 0
&& (length & 0x0fff) != 0
&& (length & (maxpacket - 1)) == 0) {
maxpacket = length;
is_rndis = 1;
}
} else {
/* virtually nothing except mass storage class */
if (length > 0xffff) {
n_bds = 0xffff / maxpacket;
length = n_bds * maxpacket;
} else {
n_bds = length / maxpacket;
if (length % maxpacket)
n_bds++;
}
if (n_bds == 1)
onepacket = 1;
else
n_bds = min(n_bds, (unsigned) NUM_RXCHAN_BD);
}
/* In host mode, autorequest logic can generate some IN tokens; it's
* tricky since we can't leave REQPKT set in RXCSR after the transfer
* finishes. So: multipacket transfers involve two or more segments.
* And always at least two IRQs ... RNDIS mode is not an option.
*/
if (is_host_active(musb))
n_bds = cppi_autoreq_update(rx, tibase, onepacket, n_bds);
cppi_rndis_update(rx, 1, musb->ctrl_base, is_rndis);
length = min(n_bds * maxpacket, length);
DBG(4, "RX DMA%d seg, maxp %d %s bds %d (cnt %d) "
"dma 0x%x len %u %u/%u\n",
rx->index, maxpacket,
onepacket
? (is_rndis ? "rndis" : "onepacket")
: "multipacket",
n_bds,
musb_readl(tibase,
DAVINCI_RXCPPI_BUFCNT0_REG + (rx->index * 4))
& 0xffff,
addr, length, rx->channel.actual_len, rx->buf_len);
/* only queue one segment at a time, since the hardware prevents
* correct queue shutdown after unexpected short packets
*/
bd = cppi_bd_alloc(rx);
rx->head = bd;
/* Build BDs for all packets in this segment */
for (i = 0, tail = NULL; bd && i < n_bds; i++, tail = bd) {
u32 bd_len;
if (i) {
bd = cppi_bd_alloc(rx);
if (!bd)
break;
tail->next = bd;
tail->hw_next = bd->dma;
}
bd->hw_next = 0;
/* all but the last packet will be maxpacket size */
if (maxpacket < length)
bd_len = maxpacket;
else
bd_len = length;
bd->hw_bufp = addr;
addr += bd_len;
rx->offset += bd_len;
bd->hw_off_len = (0 /*offset*/ << 16) + bd_len;
bd->buflen = bd_len;
bd->hw_options = CPPI_OWN_SET | (i == 0 ? length : 0);
length -= bd_len;
}
/* we always expect at least one reusable BD! */
if (!tail) {
WARNING("rx dma%d -- no BDs? need %d\n", rx->index, n_bds);
return;
} else if (i < n_bds)
WARNING("rx dma%d -- only %d of %d BDs\n", rx->index, i, n_bds);
tail->next = NULL;
tail->hw_next = 0;
bd = rx->head;
rx->tail = tail;
/* short reads and other faults should terminate this entire
* dma segment. we want one "dma packet" per dma segment, not
* one per USB packet, terminating the whole queue at once...
* NOTE that current hardware seems to ignore SOP and EOP.
*/
bd->hw_options |= CPPI_SOP_SET;
tail->hw_options |= CPPI_EOP_SET;
#ifdef CONFIG_USB_MUSB_DEBUG
if (_dbg_level(5)) {
struct cppi_descriptor *d;
for (d = rx->head; d; d = d->next)
cppi_dump_rxbd("S", d);
}
#endif
/* in case the preceding transfer left some state... */
tail = rx->last_processed;
if (tail) {
tail->next = bd;
tail->hw_next = bd->dma;
}
core_rxirq_enable(tibase, rx->index + 1);
/* BDs live in DMA-coherent memory, but writes might be pending */
cpu_drain_writebuffer();
/* REVISIT specs say to write this AFTER the BUFCNT register
* below ... but that loses badly.
*/
musb_writel(&rx_ram->rx_head, 0, bd->dma);
/* bufferCount must be at least 3, and zeroes on completion
* unless it underflows below zero, or stops at two, or keeps
* growing ... grr.
*/
i = musb_readl(tibase,
DAVINCI_RXCPPI_BUFCNT0_REG + (rx->index * 4))
& 0xffff;
if (!i)
musb_writel(tibase,
DAVINCI_RXCPPI_BUFCNT0_REG + (rx->index * 4),
n_bds + 2);
else if (n_bds > (i - 3))
musb_writel(tibase,
DAVINCI_RXCPPI_BUFCNT0_REG + (rx->index * 4),
n_bds - (i - 3));
i = musb_readl(tibase,
DAVINCI_RXCPPI_BUFCNT0_REG + (rx->index * 4))
& 0xffff;
if (i < (2 + n_bds)) {
DBG(2, "bufcnt%d underrun - %d (for %d)\n",
rx->index, i, n_bds);
musb_writel(tibase,
DAVINCI_RXCPPI_BUFCNT0_REG + (rx->index * 4),
n_bds + 2);
}
cppi_dump_rx(4, rx, "/S");
}
/**
* cppi_channel_program - program channel for data transfer
* @ch: the channel
* @maxpacket: max packet size
* @mode: For RX, 1 unless the usb protocol driver promised to treat
* all short reads as errors and kick in high level fault recovery.
* For TX, ignored because of RNDIS mode races/glitches.
* @dma_addr: dma address of buffer
* @len: length of buffer
* Context: controller irqlocked
*/
static int cppi_channel_program(struct dma_channel *ch,
u16 maxpacket, u8 mode,
dma_addr_t dma_addr, u32 len)
{
struct cppi_channel *cppi_ch;
struct cppi *controller;
struct musb *musb;
cppi_ch = container_of(ch, struct cppi_channel, channel);
controller = cppi_ch->controller;
musb = controller->musb;
switch (ch->status) {
case MUSB_DMA_STATUS_BUS_ABORT:
case MUSB_DMA_STATUS_CORE_ABORT:
/* fault irq handler should have handled cleanup */
WARNING("%cX DMA%d not cleaned up after abort!\n",
cppi_ch->transmit ? 'T' : 'R',
cppi_ch->index);
/* WARN_ON(1); */
break;
case MUSB_DMA_STATUS_BUSY:
WARNING("program active channel? %cX DMA%d\n",
cppi_ch->transmit ? 'T' : 'R',
cppi_ch->index);
/* WARN_ON(1); */
break;
case MUSB_DMA_STATUS_UNKNOWN:
DBG(1, "%cX DMA%d not allocated!\n",
cppi_ch->transmit ? 'T' : 'R',
cppi_ch->index);
/* FALLTHROUGH */
case MUSB_DMA_STATUS_FREE:
break;
}
ch->status = MUSB_DMA_STATUS_BUSY;
/* set transfer parameters, then queue up its first segment */
cppi_ch->buf_dma = dma_addr;
cppi_ch->offset = 0;
cppi_ch->maxpacket = maxpacket;
cppi_ch->buf_len = len;
cppi_ch->channel.actual_len = 0;
/* TX channel? or RX? */
if (cppi_ch->transmit)
cppi_next_tx_segment(musb, cppi_ch);
else
cppi_next_rx_segment(musb, cppi_ch, mode);
return true;
}
static bool cppi_rx_scan(struct cppi *cppi, unsigned ch)
{
struct cppi_channel *rx = &cppi->rx[ch];
struct cppi_rx_stateram __iomem *state = rx->state_ram;
struct cppi_descriptor *bd;
struct cppi_descriptor *last = rx->last_processed;
bool completed = false;
bool acked = false;
int i;
dma_addr_t safe2ack;
void __iomem *regs = rx->hw_ep->regs;
cppi_dump_rx(6, rx, "/K");
bd = last ? last->next : rx->head;
if (!bd)
return false;
/* run through all completed BDs */
for (i = 0, safe2ack = musb_readl(&state->rx_complete, 0);
(safe2ack || completed) && bd && i < NUM_RXCHAN_BD;
i++, bd = bd->next) {
u16 len;
/* catch latest BD writes from CPPI */
rmb();
if (!completed && (bd->hw_options & CPPI_OWN_SET))
break;
DBG(5, "C/RXBD %08x: nxt %08x buf %08x "
"off.len %08x opt.len %08x (%d)\n",
bd->dma, bd->hw_next, bd->hw_bufp,
bd->hw_off_len, bd->hw_options,
rx->channel.actual_len);
/* actual packet received length */
if ((bd->hw_options & CPPI_SOP_SET) && !completed)
len = bd->hw_off_len & CPPI_RECV_PKTLEN_MASK;
else
len = 0;
if (bd->hw_options & CPPI_EOQ_MASK)
completed = true;
if (!completed && len < bd->buflen) {
/* NOTE: when we get a short packet, RXCSR_H_REQPKT
* must have been cleared, and no more DMA packets may
* active be in the queue... TI docs didn't say, but
* CPPI ignores those BDs even though OWN is still set.
*/
completed = true;
DBG(3, "rx short %d/%d (%d)\n",
len, bd->buflen,
rx->channel.actual_len);
}
/* If we got here, we expect to ack at least one BD; meanwhile
* CPPI may completing other BDs while we scan this list...
*
* RACE: we can notice OWN cleared before CPPI raises the
* matching irq by writing that BD as the completion pointer.
* In such cases, stop scanning and wait for the irq, avoiding
* lost acks and states where BD ownership is unclear.
*/
if (bd->dma == safe2ack) {
musb_writel(&state->rx_complete, 0, safe2ack);
safe2ack = musb_readl(&state->rx_complete, 0);
acked = true;
if (bd->dma == safe2ack)
safe2ack = 0;
}
rx->channel.actual_len += len;
cppi_bd_free(rx, last);
last = bd;
/* stop scanning on end-of-segment */
if (bd->hw_next == 0)
completed = true;
}
rx->last_processed = last;
/* dma abort, lost ack, or ... */
if (!acked && last) {
int csr;
if (safe2ack == 0 || safe2ack == rx->last_processed->dma)
musb_writel(&state->rx_complete, 0, safe2ack);
if (safe2ack == 0) {
cppi_bd_free(rx, last);
rx->last_processed = NULL;
/* if we land here on the host side, H_REQPKT will
* be clear and we need to restart the queue...
*/
WARN_ON(rx->head);
}
musb_ep_select(cppi->mregs, rx->index + 1);
csr = musb_readw(regs, MUSB_RXCSR);
if (csr & MUSB_RXCSR_DMAENAB) {
DBG(4, "list%d %p/%p, last %08x%s, csr %04x\n",
rx->index,
rx->head, rx->tail,
rx->last_processed
? rx->last_processed->dma
: 0,
completed ? ", completed" : "",
csr);
cppi_dump_rxq(4, "/what?", rx);
}
}
if (!completed) {
int csr;
rx->head = bd;
/* REVISIT seems like "autoreq all but EOP" doesn't...
* setting it here "should" be racey, but seems to work
*/
csr = musb_readw(rx->hw_ep->regs, MUSB_RXCSR);
if (is_host_active(cppi->musb)
&& bd
&& !(csr & MUSB_RXCSR_H_REQPKT)) {
csr |= MUSB_RXCSR_H_REQPKT;
musb_writew(regs, MUSB_RXCSR,
MUSB_RXCSR_H_WZC_BITS | csr);
csr = musb_readw(rx->hw_ep->regs, MUSB_RXCSR);
}
} else {
rx->head = NULL;
rx->tail = NULL;
}
cppi_dump_rx(6, rx, completed ? "/completed" : "/cleaned");
return completed;
}
irqreturn_t cppi_interrupt(int irq, void *dev_id)
{
struct musb *musb = dev_id;
struct cppi *cppi;
void __iomem *tibase;
struct musb_hw_ep *hw_ep = NULL;
u32 rx, tx;
int i, index;
unsigned long flags;
cppi = container_of(musb->dma_controller, struct cppi, controller);
if (cppi->irq)
spin_lock_irqsave(&musb->lock, flags);
tibase = musb->ctrl_base;
tx = musb_readl(tibase, DAVINCI_TXCPPI_MASKED_REG);
rx = musb_readl(tibase, DAVINCI_RXCPPI_MASKED_REG);
if (!tx && !rx)
return IRQ_NONE;
DBG(4, "CPPI IRQ Tx%x Rx%x\n", tx, rx);
/* process TX channels */
for (index = 0; tx; tx = tx >> 1, index++) {
struct cppi_channel *tx_ch;
struct cppi_tx_stateram __iomem *tx_ram;
bool completed = false;
struct cppi_descriptor *bd;
if (!(tx & 1))
continue;
tx_ch = cppi->tx + index;
tx_ram = tx_ch->state_ram;
/* FIXME need a cppi_tx_scan() routine, which
* can also be called from abort code
*/
cppi_dump_tx(5, tx_ch, "/E");
bd = tx_ch->head;
/*
* If Head is null then this could mean that a abort interrupt
* that needs to be acknowledged.
*/
if (NULL == bd) {
DBG(1, "null BD\n");
tx_ram->tx_complete = 0;
continue;
}
/* run through all completed BDs */
for (i = 0; !completed && bd && i < NUM_TXCHAN_BD;
i++, bd = bd->next) {
u16 len;
/* catch latest BD writes from CPPI */
rmb();
if (bd->hw_options & CPPI_OWN_SET)
break;
DBG(5, "C/TXBD %p n %x b %x off %x opt %x\n",
bd, bd->hw_next, bd->hw_bufp,
bd->hw_off_len, bd->hw_options);
len = bd->hw_off_len & CPPI_BUFFER_LEN_MASK;
tx_ch->channel.actual_len += len;
tx_ch->last_processed = bd;
/* write completion register to acknowledge
* processing of completed BDs, and possibly
* release the IRQ; EOQ might not be set ...
*
* REVISIT use the same ack strategy as rx
*
* REVISIT have observed bit 18 set; huh??
*/
/* if ((bd->hw_options & CPPI_EOQ_MASK)) */
musb_writel(&tx_ram->tx_complete, 0, bd->dma);
/* stop scanning on end-of-segment */
if (bd->hw_next == 0)
completed = true;
}
/* on end of segment, maybe go to next one */
if (completed) {
/* cppi_dump_tx(4, tx_ch, "/complete"); */
/* transfer more, or report completion */
if (tx_ch->offset >= tx_ch->buf_len) {
tx_ch->head = NULL;
tx_ch->tail = NULL;
tx_ch->channel.status = MUSB_DMA_STATUS_FREE;
hw_ep = tx_ch->hw_ep;
musb_dma_completion(musb, index + 1, 1);
} else {
/* Bigger transfer than we could fit in
* that first batch of descriptors...
*/
cppi_next_tx_segment(musb, tx_ch);
}
} else
tx_ch->head = bd;
}
/* Start processing the RX block */
for (index = 0; rx; rx = rx >> 1, index++) {
if (rx & 1) {
struct cppi_channel *rx_ch;
rx_ch = cppi->rx + index;
/* let incomplete dma segments finish */
if (!cppi_rx_scan(cppi, index))
continue;
/* start another dma segment if needed */
if (rx_ch->channel.actual_len != rx_ch->buf_len
&& rx_ch->channel.actual_len
== rx_ch->offset) {
cppi_next_rx_segment(musb, rx_ch, 1);
continue;
}
/* all segments completed! */
rx_ch->channel.status = MUSB_DMA_STATUS_FREE;
hw_ep = rx_ch->hw_ep;
core_rxirq_disable(tibase, index + 1);
musb_dma_completion(musb, index + 1, 0);
}
}
/* write to CPPI EOI register to re-enable interrupts */
musb_writel(tibase, DAVINCI_CPPI_EOI_REG, 0);
if (cppi->irq)
spin_unlock_irqrestore(&musb->lock, flags);
return IRQ_HANDLED;
}
/* Instantiate a software object representing a DMA controller. */
struct dma_controller *__init
dma_controller_create(struct musb *musb, void __iomem *mregs)
{
struct cppi *controller;
struct device *dev = musb->controller;
struct platform_device *pdev = to_platform_device(dev);
int irq = platform_get_irq(pdev, 1);
controller = kzalloc(sizeof *controller, GFP_KERNEL);
if (!controller)
return NULL;
controller->mregs = mregs;
controller->tibase = mregs - DAVINCI_BASE_OFFSET;
controller->musb = musb;
controller->controller.start = cppi_controller_start;
controller->controller.stop = cppi_controller_stop;
controller->controller.channel_alloc = cppi_channel_allocate;
controller->controller.channel_release = cppi_channel_release;
controller->controller.channel_program = cppi_channel_program;
controller->controller.channel_abort = cppi_channel_abort;
/* NOTE: allocating from on-chip SRAM would give the least
* contention for memory access, if that ever matters here.
*/
/* setup BufferPool */
controller->pool = dma_pool_create("cppi",
controller->musb->controller,
sizeof(struct cppi_descriptor),
CPPI_DESCRIPTOR_ALIGN, 0);
if (!controller->pool) {
kfree(controller);
return NULL;
}
if (irq > 0) {
if (request_irq(irq, cppi_interrupt, 0, "cppi-dma", musb)) {
dev_err(dev, "request_irq %d failed!\n", irq);
dma_controller_destroy(&controller->controller);
return NULL;
}
controller->irq = irq;
}
return &controller->controller;
}
/*
* Destroy a previously-instantiated DMA controller.
*/
void dma_controller_destroy(struct dma_controller *c)
{
struct cppi *cppi;
cppi = container_of(c, struct cppi, controller);
if (cppi->irq)
free_irq(cppi->irq, cppi->musb);
/* assert: caller stopped the controller first */
dma_pool_destroy(cppi->pool);
kfree(cppi);
}
/*
* Context: controller irqlocked, endpoint selected
*/
static int cppi_channel_abort(struct dma_channel *channel)
{
struct cppi_channel *cppi_ch;
struct cppi *controller;
void __iomem *mbase;
void __iomem *tibase;
void __iomem *regs;
u32 value;
struct cppi_descriptor *queue;
cppi_ch = container_of(channel, struct cppi_channel, channel);
controller = cppi_ch->controller;
switch (channel->status) {
case MUSB_DMA_STATUS_BUS_ABORT:
case MUSB_DMA_STATUS_CORE_ABORT:
/* from RX or TX fault irq handler */
case MUSB_DMA_STATUS_BUSY:
/* the hardware needs shutting down */
regs = cppi_ch->hw_ep->regs;
break;
case MUSB_DMA_STATUS_UNKNOWN:
case MUSB_DMA_STATUS_FREE:
return 0;
default:
return -EINVAL;
}
if (!cppi_ch->transmit && cppi_ch->head)
cppi_dump_rxq(3, "/abort", cppi_ch);
mbase = controller->mregs;
tibase = controller->tibase;
queue = cppi_ch->head;
cppi_ch->head = NULL;
cppi_ch->tail = NULL;
/* REVISIT should rely on caller having done this,
* and caller should rely on us not changing it.
* peripheral code is safe ... check host too.
*/
musb_ep_select(mbase, cppi_ch->index + 1);
if (cppi_ch->transmit) {
struct cppi_tx_stateram __iomem *tx_ram;
/* REVISIT put timeouts on these controller handshakes */
cppi_dump_tx(6, cppi_ch, " (teardown)");
/* teardown DMA engine then usb core */
do {
value = musb_readl(tibase, DAVINCI_TXCPPI_TEAR_REG);
} while (!(value & CPPI_TEAR_READY));
musb_writel(tibase, DAVINCI_TXCPPI_TEAR_REG, cppi_ch->index);
tx_ram = cppi_ch->state_ram;
do {
value = musb_readl(&tx_ram->tx_complete, 0);
} while (0xFFFFFFFC != value);
/* FIXME clean up the transfer state ... here?
* the completion routine should get called with
* an appropriate status code.
*/
value = musb_readw(regs, MUSB_TXCSR);
value &= ~MUSB_TXCSR_DMAENAB;
value |= MUSB_TXCSR_FLUSHFIFO;
musb_writew(regs, MUSB_TXCSR, value);
musb_writew(regs, MUSB_TXCSR, value);
/*
* 1. Write to completion Ptr value 0x1(bit 0 set)
* (write back mode)
* 2. Wait for abort interrupt and then put the channel in
* compare mode by writing 1 to the tx_complete register.
*/
cppi_reset_tx(tx_ram, 1);
cppi_ch->head = 0;
musb_writel(&tx_ram->tx_complete, 0, 1);
cppi_dump_tx(5, cppi_ch, " (done teardown)");
/* REVISIT tx side _should_ clean up the same way
* as the RX side ... this does no cleanup at all!
*/
} else /* RX */ {
u16 csr;
/* NOTE: docs don't guarantee any of this works ... we
* expect that if the usb core stops telling the cppi core
* to pull more data from it, then it'll be safe to flush
* current RX DMA state iff any pending fifo transfer is done.
*/
core_rxirq_disable(tibase, cppi_ch->index + 1);
/* for host, ensure ReqPkt is never set again */
if (is_host_active(cppi_ch->controller->musb)) {
value = musb_readl(tibase, DAVINCI_AUTOREQ_REG);
value &= ~((0x3) << (cppi_ch->index * 2));
musb_writel(tibase, DAVINCI_AUTOREQ_REG, value);
}
csr = musb_readw(regs, MUSB_RXCSR);
/* for host, clear (just) ReqPkt at end of current packet(s) */
if (is_host_active(cppi_ch->controller->musb)) {
csr |= MUSB_RXCSR_H_WZC_BITS;
csr &= ~MUSB_RXCSR_H_REQPKT;
} else
csr |= MUSB_RXCSR_P_WZC_BITS;
/* clear dma enable */
csr &= ~(MUSB_RXCSR_DMAENAB);
musb_writew(regs, MUSB_RXCSR, csr);
csr = musb_readw(regs, MUSB_RXCSR);
/* Quiesce: wait for current dma to finish (if not cleanup).
* We can't use bit zero of stateram->rx_sop, since that
* refers to an entire "DMA packet" not just emptying the
* current fifo. Most segments need multiple usb packets.
*/
if (channel->status == MUSB_DMA_STATUS_BUSY)
udelay(50);
/* scan the current list, reporting any data that was
* transferred and acking any IRQ
*/
cppi_rx_scan(controller, cppi_ch->index);
/* clobber the existing state once it's idle
*
* NOTE: arguably, we should also wait for all the other
* RX channels to quiesce (how??) and then temporarily
* disable RXCPPI_CTRL_REG ... but it seems that we can
* rely on the controller restarting from state ram, with
* only RXCPPI_BUFCNT state being bogus. BUFCNT will
* correct itself after the next DMA transfer though.
*
* REVISIT does using rndis mode change that?
*/
cppi_reset_rx(cppi_ch->state_ram);
/* next DMA request _should_ load cppi head ptr */
/* ... we don't "free" that list, only mutate it in place. */
cppi_dump_rx(5, cppi_ch, " (done abort)");
/* clean up previously pending bds */
cppi_bd_free(cppi_ch, cppi_ch->last_processed);
cppi_ch->last_processed = NULL;
while (queue) {
struct cppi_descriptor *tmp = queue->next;
cppi_bd_free(cppi_ch, queue);
queue = tmp;
}
}
channel->status = MUSB_DMA_STATUS_FREE;
cppi_ch->buf_dma = 0;
cppi_ch->offset = 0;
cppi_ch->buf_len = 0;
cppi_ch->maxpacket = 0;
return 0;
}
/* TBD Queries:
*
* Power Management ... probably turn off cppi during suspend, restart;
* check state ram? Clocking is presumably shared with usb core.
*/