Date: Wed, 2 Mar 2011 14:53:18 -0700 (MST) From: Ian Lepore <freebsd@damnhippie.dyndns.org> To: FreeBSD-gnats-submit@FreeBSD.org Subject: arm/155214: [patch] MMC/SD IO slow on Atmel ARM with modern large SD cards Message-ID: <201103022153.p22LrIhP097307@revolution.hippie.lan> Resent-Message-ID: <201103022210.p22MABmL078817@freefall.freebsd.org>
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>Number: 155214
>Category: arm
>Synopsis: [patch] MMC/SD IO slow on Atmel ARM with modern large SD cards
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-arm
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Wed Mar 02 22:10:10 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator: Ian Lepore <freebsd@damnhippie.dyndns.org>
>Release: FreeBSD 8.2-RC3 arm
>Organization:
none
>Environment:
FreeBSD dvb 8.2-RC3 FreeBSD 8.2-RC3 #49: Tue Feb 15 22:52:14 UTC 2011 root@revolution.hippie.lan:/usr/obj/arm/usr/src/sys/DVB arm
Included patch is against -current even though the problem was first seen on
8.2-RC3
The problem was seen on AT91RM9200 hardware, but presumably also affects the
SAM9 series which uses the same driver code.
>Description:
With the latest generation of large-capacity SD cards, write speeds as low as
20 kbytes/sec are seen. These modern cards have erase-block sizes as large as
8192K (compared to 32K typical on previous generations). The at91_mci driver
does only single-sector IO; apparently this requires the SD card to internally
perform an expensive read-erase-modify-write cycle for each 512 byte block
written to the card.
It should be noted that even with older SD cards that have smaller erase-block
sizes, write throughput to the card rarely exceeds about 350 kbytes/sec; still
very slow for modern hardware.
With the patch provided, write throughput improves to approximately
1500 kbytes/sec. Read speeds also improve (was 640, now 2400 kbytes/sec).
>How-To-Repeat:
The slow IO can be demonstrated using dd to write directly to the device
(bypassing buffering and caching at higher layers):
dvb# dd if=/dev/zero of=/dev/mmcsd0s2a bs=64k count=100
100+0 records in
100+0 records out
6553600 bytes transferred in 266.252838 secs (24614 bytes/sec)
dvb# dd if=/dev/zero of=/dev/mmcsd0s2a bs=6400k count=1
1+0 records in
1+0 records out
6553600 bytes transferred in 265.004883 secs (24730 bytes/sec)
>Fix:
The following patch adds support for multi-block IO to the at91_mci driver.
The patch is to -current even though the problem was discovered in 8.2-RC3.
The patched driver will also work in 8.2, but requires a few other items in
the arm/at91 directory to be back-ported as well (to support references to
things such as at91_master_clock and at91_is_rm9200)).
--- patch-arm-at91_mci-for-multiblock begins here ---
--- sys/arm/at91/at91_mci.c.cvs_v1.18 2011-02-28 13:43:54.000000000 -0700
+++ sys/arm/at91/at91_mci.c 2011-03-02 07:21:38.000000000 -0700
@@ -67,7 +67,13 @@
#include "opt_at91.h"
-#define BBSZ 512
+#ifndef AT91_MCI_MAX_BLOCKS
+#define AT91_MCI_MAX_BLOCKS 64 /* default 32k bounce buffer */
+#endif
+
+#define BBSIZE (AT91_MCI_MAX_BLOCKS * 512)
+
+static int mci_debug;
struct at91_mci_softc {
void *intrhand; /* Interrupt handle */
@@ -75,21 +81,24 @@
int sc_cap;
#define CAP_HAS_4WIRE 1 /* Has 4 wire bus */
#define CAP_NEEDS_BYTESWAP 2 /* broken hardware needing bounce */
- int flags;
int has_4wire;
-#define CMD_STARTED 1
-#define STOP_STARTED 2
+ int flags;
+#define PENDING_CMD 0x01
+#define PENDING_STOP 0x02
+#define PENDING_ERROR 0x04
+#define CMD_MULTIREAD 0x10
+#define CMD_MULTIWRITE 0x20
struct resource *irq_res; /* IRQ resource */
struct resource *mem_res; /* Memory resource */
struct mtx sc_mtx;
bus_dma_tag_t dmatag;
bus_dmamap_t map;
- int mapped;
struct mmc_host host;
int bus_busy;
struct mmc_request *req;
struct mmc_command *curcmd;
- char bounce_buffer[BBSZ];
+ char *bbuf_vaddr; /* bounce buf in KVA space */
+ bus_addr_t bbuf_paddr; /* bounce buf mapped into DMA space */
};
static inline uint32_t
@@ -124,6 +133,14 @@
#define AT91_MCI_ASSERT_UNLOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_NOTOWNED);
static void
+at91_mci_getaddr(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
+{
+ if (error != 0)
+ return;
+ *(bus_addr_t *)arg = segs[0].ds_addr;
+}
+
+static void
at91_mci_pdc_disable(struct at91_mci_softc *sc)
{
WR4(sc, PDC_PTCR, PDC_PTCR_TXTDIS | PDC_PTCR_RXTDIS);
@@ -137,6 +154,48 @@
WR4(sc, PDC_TNCR, 0);
}
+/* Reset the controller, then restore most of the current state.
+ *
+ * This is called after detecting an error. It's also called after stopping a
+ * multi-block write, to un-wedge the device so that it will handle the NOTBUSY
+ * signal correctly. See comments in at91_mci_stop_done() for more details.
+ */
+static void at91_mci_reset(struct at91_mci_softc *sc)
+{
+ uint32_t mr;
+ uint32_t sdcr;
+ uint32_t dtor;
+ uint32_t imr;
+
+ at91_mci_pdc_disable(sc);
+
+ /* save current state */
+
+ imr = RD4(sc, MCI_IMR);
+ mr = RD4(sc, MCI_MR) & 0x7fff;
+ sdcr = RD4(sc, MCI_SDCR);
+ dtor = RD4(sc, MCI_DTOR);
+
+ /* reset the controller */
+
+ WR4(sc, MCI_IDR, 0xffffffff);
+ WR4(sc, MCI_CR, MCI_CR_MCIDIS | MCI_CR_SWRST);
+
+ /* restore state */
+
+ WR4(sc, MCI_CR, MCI_CR_MCIEN);
+ WR4(sc, MCI_MR, mr);
+ WR4(sc, MCI_SDCR, sdcr);
+ WR4(sc, MCI_DTOR, dtor);
+ WR4(sc, MCI_IER, imr);
+
+ /* Make sure sdio interrupts will fire. Not sure why reading
+ * SR ensures that, but this is in the linux driver.
+ */
+
+ RD4(sc, MCI_SR);
+}
+
static void
at91_mci_init(device_t dev)
{
@@ -145,7 +204,7 @@
WR4(sc, MCI_CR, MCI_CR_MCIEN); /* Enable controller */
WR4(sc, MCI_IDR, 0xffffffff); /* Turn off interrupts */
WR4(sc, MCI_DTOR, MCI_DTOR_DTOMUL_1M | 1);
- WR4(sc, MCI_MR, 0x834a); // XXX GROSS HACK FROM LINUX
+ WR4(sc, MCI_MR, 0x834a); // set PDCMODE, PWSDIV=3, CLKDIV=75
#ifndef AT91_MCI_SLOT_B
WR4(sc, MCI_SDCR, 0); /* SLOT A, 1 bit bus */
#else
@@ -168,7 +227,6 @@
static int
at91_mci_probe(device_t dev)
{
-
device_set_desc(dev, "MCI mmc/sd host bridge");
return (0);
}
@@ -193,24 +251,44 @@
AT91_MCI_LOCK_INIT(sc);
- /*
- * Allocate DMA tags and maps
+ at91_mci_fini(dev);
+ at91_mci_init(dev);
+
+ /* Allocate DMA tags and maps and a physically-contiguous bounce buffer.
+ *
+ * The parms in the tag_create call cause the dmamem_alloc call to
+ * create a single contiguous buffer of BBSIZE bytes aligned to a 4096
+ * byte boundary.
+ *
+ * Allocate the bounce buffer using DMA_COHERENT which in effect means
+ * that the pages are mapped as non-cacheable (making all the
+ * bus_dmamap_sync() calls become fast no-ops) because there's no value
+ * in caching the data in the swap/bounce buffers (there would just be
+ * extra overhead in flushing the caches after the data has been
+ * accessed exactly once).
+ *
+ * After allocating the bounce buffer we load the map for it and leave
+ * it loaded as long as the driver is active.
*/
- err = bus_dma_tag_create(bus_get_dma_tag(dev), 1, 0,
- BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL, NULL, MAXPHYS, 1,
- MAXPHYS, BUS_DMA_ALLOCNOW, NULL, NULL, &sc->dmatag);
+
+ err = bus_dma_tag_create(bus_get_dma_tag(dev), 4096, 0,
+ BUS_SPACE_MAXADDR_32BIT, BUS_SPACE_MAXADDR, NULL, NULL,
+ BBSIZE, 1, MAXPHYS, 0, NULL, NULL, &sc->dmatag);
if (err != 0)
goto out;
- err = bus_dmamap_create(sc->dmatag, 0, &sc->map);
+ err = bus_dmamem_alloc(sc->dmatag, (void **)&sc->bbuf_vaddr,
+ BUS_DMA_NOWAIT|BUS_DMA_COHERENT, &sc->map);
if (err != 0)
goto out;
- at91_mci_fini(dev);
- at91_mci_init(dev);
+ err = bus_dmamap_load(sc->dmatag, sc->map, sc->bbuf_vaddr, BBSIZE,
+ at91_mci_getaddr, &sc->bbuf_paddr, BUS_DMA_NOWAIT);
+ if (err != 0)
+ goto out;
/*
- * Activate the interrupt
+ * Set up to handle interrupts.
*/
err = bus_setup_intr(dev, sc->irq_res, INTR_TYPE_MISC | INTR_MPSAFE,
at91_mci_intr, sc, &sc->intrhand);
@@ -230,10 +308,13 @@
if (sc->has_4wire)
sc->sc_cap |= CAP_HAS_4WIRE;
- sc->host.f_min = at91_master_clock / 512;
+ /* Our real min freq is master_clock/512, but upper driver layers are
+ * going to set the min speed during card discovery, and the right speed
+ * for that is 400khz, so advertise a safe value just under that.
+ */
sc->host.f_min = 375000;
sc->host.f_max = at91_master_clock / 2;
- if (sc->host.f_max > 50000000)
+ if (sc->host.f_max > 50000000)
sc->host.f_max = 50000000; /* Limit to 50MHz */
sc->host.host_ocr = MMC_OCR_320_330 | MMC_OCR_330_340;
@@ -252,8 +333,15 @@
static int
at91_mci_detach(device_t dev)
{
+ struct at91_mci_softc *sc = device_get_softc(dev);
+
at91_mci_fini(dev);
at91_mci_deactivate(dev);
+
+ bus_dmamap_unload(sc->dmatag, sc->map);
+ bus_dmamem_free(sc->dmatag, sc->bbuf_vaddr, sc->map);
+ bus_dma_tag_destroy(sc->dmatag);
+
return (EBUSY); /* XXX */
}
@@ -293,7 +381,7 @@
sc->intrhand = 0;
bus_generic_detach(sc->dev);
if (sc->mem_res)
- bus_release_resource(dev, SYS_RES_IOPORT,
+ bus_release_resource(dev, SYS_RES_MEMORY,
rman_get_rid(sc->mem_res), sc->mem_res);
sc->mem_res = 0;
if (sc->irq_res)
@@ -303,14 +391,6 @@
return;
}
-static void
-at91_mci_getaddr(void *arg, bus_dma_segment_t *segs, int nsegs, int error)
-{
- if (error != 0)
- return;
- *(bus_addr_t *)arg = segs[0].ds_addr;
-}
-
static int
at91_mci_update_ios(device_t brdev, device_t reqdev)
{
@@ -322,7 +402,7 @@
sc = device_get_softc(brdev);
host = &sc->host;
ios = &host->ios;
- // bus mode?
+
if (ios->clock == 0) {
WR4(sc, MCI_CR, MCI_CR_MCIDIS);
clkdiv = 0;
@@ -346,137 +426,176 @@
static void
at91_mci_start_cmd(struct at91_mci_softc *sc, struct mmc_command *cmd)
{
- uint32_t cmdr, ier = 0, mr;
+ uint32_t cmdr, mr;
uint32_t *src, *dst;
int i;
struct mmc_data *data;
- void *vaddr;
- bus_addr_t paddr;
sc->curcmd = cmd;
data = cmd->data;
- cmdr = cmd->opcode;
/* XXX Upper layers don't always set this */
cmd->mrq = sc->req;
+ /* Begin setting up command register. */
+
+ cmdr = cmd->opcode;
+
+ if (sc->host.ios.bus_mode == opendrain)
+ cmdr |= MCI_CMDR_OPDCMD;
+
+ /* Set up response handling. Allow max timeout for responses. */
+
if (MMC_RSP(cmd->flags) == MMC_RSP_NONE)
cmdr |= MCI_CMDR_RSPTYP_NO;
else {
- /* Allow big timeout for responses */
cmdr |= MCI_CMDR_MAXLAT;
if (cmd->flags & MMC_RSP_136)
cmdr |= MCI_CMDR_RSPTYP_136;
else
cmdr |= MCI_CMDR_RSPTYP_48;
}
- if (cmd->opcode == MMC_STOP_TRANSMISSION)
- cmdr |= MCI_CMDR_TRCMD_STOP;
- if (sc->host.ios.bus_mode == opendrain)
- cmdr |= MCI_CMDR_OPDCMD;
- if (!data) {
- // The no data case is fairly simple
+
+ /* If there is no data transfer, just set up the right interrupt mask
+ * and start the command.
+ *
+ * The interrupt mask needs to be CMDRDY plus all non-data-transfer
+ * errors. It's important to leave the transfer-related errors out, to
+ * avoid spurious timeout or crc errors on a STOP command following a
+ * multiblock read. When a multiblock read is in progress, sending a
+ * STOP in the middle of a block occasionally triggers such errors, but
+ * we're totally disinterested in them because we've already gotten all
+ * the data we wanted without error before sending the STOP command.
+ */
+
+ if (data == NULL) {
+ uint32_t ier = MCI_SR_CMDRDY |
+ MCI_SR_RTOE | MCI_SR_RENDE |
+ MCI_SR_RCRCE | MCI_SR_RDIRE | MCI_SR_RINDE;
+
at91_mci_pdc_disable(sc);
-// printf("CMDR %x ARGR %x\n", cmdr, cmd->arg);
+
+ if (cmd->opcode == MMC_STOP_TRANSMISSION)
+ cmdr |= MCI_CMDR_TRCMD_STOP;
+
+ /* Ignore response CRC on CMD2 and ACMD41, per standard. */
+
+ if (cmd->opcode == MMC_SEND_OP_COND ||
+ cmd->opcode == ACMD_SD_SEND_OP_COND)
+ ier &= ~MCI_SR_RCRCE;
+
+ if (mci_debug)
+ printf("CMDR %x (opcode %d) ARGR %x no data\n",
+ cmdr, cmd->opcode, cmd->arg);
+
WR4(sc, MCI_ARGR, cmd->arg);
WR4(sc, MCI_CMDR, cmdr);
- WR4(sc, MCI_IER, MCI_SR_ERROR | MCI_SR_CMDRDY);
+ WR4(sc, MCI_IER, ier);
return;
}
+
+ /* There is data, set up the transfer-related parts of the command. */
+
if (data->flags & MMC_DATA_READ)
cmdr |= MCI_CMDR_TRDIR;
+
if (data->flags & (MMC_DATA_READ | MMC_DATA_WRITE))
cmdr |= MCI_CMDR_TRCMD_START;
+
if (data->flags & MMC_DATA_STREAM)
cmdr |= MCI_CMDR_TRTYP_STREAM;
- if (data->flags & MMC_DATA_MULTI)
+ else if (data->flags & MMC_DATA_MULTI) {
cmdr |= MCI_CMDR_TRTYP_MULTIPLE;
- // Set block size and turn on PDC mode for dma xfer and disable
- // PDC until we're ready.
- mr = RD4(sc, MCI_MR) & ~MCI_MR_BLKLEN;
- WR4(sc, MCI_MR, mr | (data->len << 16) | MCI_MR_PDCMODE);
- WR4(sc, PDC_PTCR, PDC_PTCR_RXTDIS | PDC_PTCR_TXTDIS);
- if (cmdr & MCI_CMDR_TRCMD_START) {
- if (cmdr & MCI_CMDR_TRDIR)
- vaddr = cmd->data->data;
- else {
- /* Use bounce buffer even if we don't need
- * byteswap, since buffer may straddle a page
- * boundry, and we don't handle multi-segment
- * transfers in hardware.
- * (page issues seen from 'bsdlabel -w' which
- * uses raw geom access to the volume).
- * Greg Ansley (gja (at) ansley.com)
- */
- vaddr = sc->bounce_buffer;
- src = (uint32_t *)cmd->data->data;
- dst = (uint32_t *)vaddr;
- if (sc->sc_cap & CAP_NEEDS_BYTESWAP) {
- for (i = 0; i < data->len / 4; i++)
- dst[i] = bswap32(src[i]);
- } else
- memcpy(dst, src, data->len);
- }
- data->xfer_len = 0;
- if (bus_dmamap_load(sc->dmatag, sc->map, vaddr, data->len,
- at91_mci_getaddr, &paddr, 0) != 0) {
- cmd->error = MMC_ERR_NO_MEMORY;
- sc->req = NULL;
- sc->curcmd = NULL;
- cmd->mrq->done(cmd->mrq);
- return;
- }
- sc->mapped++;
- if (cmdr & MCI_CMDR_TRDIR) {
+ sc->flags |= (data->flags & MMC_DATA_READ) ?
+ CMD_MULTIREAD : CMD_MULTIWRITE;
+ }
+
+ /* Disable PDC until we're ready.
+ *
+ * Set block size and turn on PDC mode for dma xfer.
+ * Note that the block size is the smaller of the amount of data to be
+ * transferred, or 512 bytes. The 512 size is fixed by the standard;
+ * smaller blocks are possible, but never larger.
+ */
+
+ WR4(sc, PDC_PTCR, PDC_PTCR_RXTDIS | PDC_PTCR_TXTDIS);
+
+ mr = RD4(sc,MCI_MR) & ~MCI_MR_BLKLEN;
+ mr |= min(data->len, 512) << 16;
+ WR4(sc, MCI_MR, mr | MCI_MR_PDCMODE);
+
+ /* Set up DMA.
+ *
+ * Use a bounce buffer even if we don't need to byteswap, because doing
+ * multi-block IO with a single large DMA buffer is way fast (compared
+ * to single-block IO), even after incurring the overhead of also
+ * copying from/to the caller's buffers (which may be in non-contiguous
+ * physical pages).
+ *
+ * In an ideal non-byteswap world we could create a dma tag that allows
+ * for discontiguous segments and do the IO directly from/to the
+ * caller's buffer(s), using ENDRX/ENDTX interrupts to chain the
+ * discontiguous buffers through the PDC. Someday.
+ *
+ * XXX what about stream transfers?
+ */
+
+ if (data->flags & (MMC_DATA_READ | MMC_DATA_WRITE)) {
+ if (data->flags & MMC_DATA_READ) {
bus_dmamap_sync(sc->dmatag, sc->map, BUS_DMASYNC_PREREAD);
- WR4(sc, PDC_RPR, paddr);
+ WR4(sc, PDC_RPR, sc->bbuf_paddr);
WR4(sc, PDC_RCR, data->len / 4);
- ier = MCI_SR_ENDRX;
+ WR4(sc, PDC_PTCR, PDC_PTCR_RXTEN);
} else {
+ if (sc->sc_cap & CAP_NEEDS_BYTESWAP) {
+ src = (uint32_t *)data->data;
+ dst = (uint32_t *)sc->bbuf_vaddr;
+ for (i = 0; i < data->len / 4; i++)
+ dst[i] = bswap32(src[i]);
+ } else {
+ bcopy(data->data, sc->bbuf_vaddr, data->len);
+ }
bus_dmamap_sync(sc->dmatag, sc->map, BUS_DMASYNC_PREWRITE);
- WR4(sc, PDC_TPR, paddr);
+ WR4(sc, PDC_TPR, sc->bbuf_paddr);
WR4(sc, PDC_TCR, data->len / 4);
- ier = MCI_SR_TXBUFE;
+ /* do not enable PDC xfer until CMDRDY asserted */
}
+ data->xfer_len = 0; /* XXX what's this? appears to be unused. */
}
-// printf("CMDR %x ARGR %x with data\n", cmdr, cmd->arg);
+
+ if (mci_debug)
+ printf("CMDR %x (opcode %d) ARGR %x with data\n", cmdr, cmd->opcode, cmd->arg);
+
WR4(sc, MCI_ARGR, cmd->arg);
- if (cmdr & MCI_CMDR_TRCMD_START) {
- if (cmdr & MCI_CMDR_TRDIR) {
- WR4(sc, PDC_PTCR, PDC_PTCR_RXTEN);
- WR4(sc, MCI_CMDR, cmdr);
- } else {
- WR4(sc, MCI_CMDR, cmdr);
- WR4(sc, PDC_PTCR, PDC_PTCR_TXTEN);
- }
- }
- WR4(sc, MCI_IER, MCI_SR_ERROR | ier);
+ WR4(sc, MCI_CMDR, cmdr);
+ WR4(sc, MCI_IER, MCI_SR_ERROR | MCI_SR_CMDRDY);
}
static void
-at91_mci_start(struct at91_mci_softc *sc)
+at91_mci_next_operation(struct at91_mci_softc *sc)
{
struct mmc_request *req;
req = sc->req;
if (req == NULL)
return;
- // assert locked
- if (!(sc->flags & CMD_STARTED)) {
- sc->flags |= CMD_STARTED;
-// printf("Starting CMD\n");
- at91_mci_start_cmd(sc, req->cmd);
- return;
- }
- if (!(sc->flags & STOP_STARTED) && req->stop) {
-// printf("Starting Stop\n");
- sc->flags |= STOP_STARTED;
- at91_mci_start_cmd(sc, req->stop);
- return;
+
+ if (!(sc->flags & PENDING_ERROR)) {
+ if (sc->flags & PENDING_CMD) {
+ sc->flags &= ~PENDING_CMD;
+ at91_mci_start_cmd(sc, req->cmd);
+ return;
+ } else if (sc->flags & PENDING_STOP) {
+ sc->flags &= ~PENDING_STOP;
+ at91_mci_start_cmd(sc, req->stop);
+ return;
+ }
}
- /* We must be done -- bad idea to do this while locked? */
+
+ WR4(sc, MCI_IDR, 0xffffffff);
sc->req = NULL;
sc->curcmd = NULL;
+ //printf("req done\n");
req->done(req);
}
@@ -486,16 +605,16 @@
struct at91_mci_softc *sc = device_get_softc(brdev);
AT91_MCI_LOCK(sc);
- // XXX do we want to be able to queue up multiple commands?
- // XXX sounds like a good idea, but all protocols are sync, so
- // XXX maybe the idea is naive...
if (sc->req != NULL) {
AT91_MCI_UNLOCK(sc);
return (EBUSY);
}
+ //printf("new req\n");
sc->req = req;
- sc->flags = 0;
- at91_mci_start(sc);
+ sc->flags = PENDING_CMD;
+ if (sc->req->stop)
+ sc->flags |= PENDING_STOP;
+ at91_mci_next_operation(sc);
AT91_MCI_UNLOCK(sc);
return (0);
}
@@ -535,118 +654,299 @@
static void
at91_mci_read_done(struct at91_mci_softc *sc)
{
- uint32_t *walker;
- struct mmc_command *cmd;
- int i, len;
+ struct mmc_command *cmd = sc->curcmd;
+
+ /* We arrive here when the entire DMA transfer for a read is done,
+ * whether it's a single or multi-block read. Either way the next thing
+ * to do is move on to the next operation. For single-block that'll
+ * mean returning the now-completed request, for multi-block it will
+ * invoke the stop command sequence.
+ */
+
+ WR4(sc, PDC_PTCR, PDC_PTCR_RXTDIS | PDC_PTCR_TXTDIS);
- cmd = sc->curcmd;
bus_dmamap_sync(sc->dmatag, sc->map, BUS_DMASYNC_POSTREAD);
- bus_dmamap_unload(sc->dmatag, sc->map);
- sc->mapped--;
+
if (sc->sc_cap & CAP_NEEDS_BYTESWAP) {
- walker = (uint32_t *)cmd->data->data;
- len = cmd->data->len / 4;
+ int i;
+ uint32_t *src = (uint32_t *)sc->bbuf_vaddr;
+ uint32_t *dst = (uint32_t *)cmd->data->data;
+ int len = cmd->data->len / 4;
for (i = 0; i < len; i++)
- walker[i] = bswap32(walker[i]);
+ dst[i] = bswap32(src[i]);
+ } else {
+ bcopy(sc->bbuf_vaddr, cmd->data->data, cmd->data->len);
}
- // Finish up the sequence...
- WR4(sc, MCI_IDR, MCI_SR_ENDRX);
- WR4(sc, MCI_IER, MCI_SR_RXBUFF);
- WR4(sc, PDC_PTCR, PDC_PTCR_RXTDIS | PDC_PTCR_TXTDIS);
+
+ cmd->error = MMC_ERR_NONE;
+ at91_mci_next_operation(sc);
}
static void
-at91_mci_xmit_done(struct at91_mci_softc *sc)
+at91_mci_write_done(struct at91_mci_softc *sc, uint32_t sr)
{
- // Finish up the sequence...
+ struct mmc_command *cmd = sc->curcmd;
+
+ /* We arrive here when the entire DMA transfer for a write is done,
+ * whether it's a single or multi-block write. If it's multi-block we
+ * have to immediately move on to the next operation which is to send
+ * the stop command. If it's a single-block transfer we need to wait
+ * for NOTBUSY, but if that's already asserted we can avoid another
+ * interrupt and just move on to completing the request right away.
+ */
+
WR4(sc, PDC_PTCR, PDC_PTCR_RXTDIS | PDC_PTCR_TXTDIS);
- WR4(sc, MCI_IDR, MCI_SR_TXBUFE);
- WR4(sc, MCI_IER, MCI_SR_NOTBUSY);
+
bus_dmamap_sync(sc->dmatag, sc->map, BUS_DMASYNC_POSTWRITE);
- bus_dmamap_unload(sc->dmatag, sc->map);
- sc->mapped--;
+
+ if ((cmd->data->flags & MMC_DATA_MULTI) || (sr & MCI_SR_NOTBUSY)) {
+ cmd->error = MMC_ERR_NONE;
+ at91_mci_next_operation(sc);
+ } else {
+ WR4(sc, MCI_IER, MCI_SR_ERROR | MCI_SR_NOTBUSY);
+ }
+}
+
+static void
+at91_mci_notbusy(struct at91_mci_softc *sc)
+{
+ struct mmc_command *cmd = sc->curcmd;
+
+ /* We arrive here by either completion of a single-block write, or
+ * completion of the stop command that ended a multi-block write (and, I
+ * suppose, after a card-select or erase, but I haven't tested those).
+ * Anyway, we're done and it's time to move on to the next command.
+ */
+
+ cmd->error = MMC_ERR_NONE;
+ at91_mci_next_operation(sc);
+}
+
+static void
+at91_mci_stop_done(struct at91_mci_softc *sc, uint32_t sr)
+{
+ struct mmc_command *cmd = sc->curcmd;
+
+ /* We arrive here after receiving CMDRDY for a MMC_STOP_TRANSMISSION
+ * command. Depending on the operation being stopped, we may have to do
+ * some unusual things to work around hardware bugs.
+ */
+
+ /* This is known to be true of at91rm9200 hardware; it may or may not
+ * apply to more recent chips:
+ *
+ * After stopping a multi-block write, the NOTBUSY bit in MCI_SR does
+ * not properly reflect the actual busy state of the card as signaled on
+ * the DAT0 line; it always claims the card is not-busy. If we believe
+ * that and let operations continue, following commands will fail with
+ * response timeouts (except of course MMC_SEND_STATUS -- it indicates
+ * the card is busy in the PRG state, which was the smoking gun that
+ * showed MCI_SR NOTBUSY was not tracking DAT0 correctly).
+ *
+ * The atmel docs are emphatic: "This flag [NOTBUSY] must be used only
+ * for Write Operations." I guess technically since we sent a stop it's
+ * not a write operation anymore. But then just what did they think it
+ * meant for the stop command to have "...an optional busy signal
+ * transmitted on the data line" according to the SD spec?
+ *
+ * I tried a variety of things to un-wedge the MCI and get the status
+ * register to reflect NOTBUSY correctly again, but the only thing that
+ * worked was a full device reset. It feels like an awfully big hammer,
+ * but doing a full reset after every multiblock write is still faster
+ * than doing single-block IO (by almost two orders of magnitude:
+ * 20KB/sec improves to about 1.8MB/sec best case).
+ *
+ * After doing the reset, wait for a NOTBUSY interrupt before continuing
+ * with the next operation.
+ */
+
+ if (sc->flags & CMD_MULTIWRITE) {
+ at91_mci_reset(sc);
+ WR4(sc, MCI_IER, MCI_SR_ERROR | MCI_SR_NOTBUSY);
+ return;
+ }
+
+ /* This is known to be true of at91rm9200 hardware; it may or may not
+ * apply to more recent chips:
+ *
+ * After stopping a multi-block read, loop to read and discard any data
+ * that coasts in after we sent the stop command. The docs don't say
+ * anything about it, but empirical testing shows that 1-3 additional
+ * words of data get buffered up in some unmentioned internal fifo and
+ * if we don't read and discard them here they end up on the front of
+ * the next read DMA transfer we do.
+ */
+
+ if (sc->flags & CMD_MULTIREAD) {
+ uint32_t sr;
+ int count = 0;
+ do {
+ sr = RD4(sc, MCI_SR);
+ if (sr & MCI_SR_RXRDY) {
+ RD4(sc, MCI_RDR);
+ ++count;
+ }
+ } while (sr & MCI_SR_RXRDY);
+// if (count != 0)
+// printf("Had to soak up %d words after read\n", count);
+ }
+
+ cmd->error = MMC_ERR_NONE;
+ at91_mci_next_operation(sc);
+
+}
+
+static void
+at91_mci_cmdrdy(struct at91_mci_softc *sc, uint32_t sr)
+{
+ struct mmc_command *cmd = sc->curcmd;
+ int i;
+
+ if (cmd == NULL)
+ return;
+
+ /* We get here at the end of EVERY command. We retrieve the command
+ * response (if any) then decide what to do next based on the command.
+ */
+
+ if (cmd->flags & MMC_RSP_PRESENT) {
+ for (i = 0; i < ((cmd->flags & MMC_RSP_136) ? 4 : 1); i++) {
+ cmd->resp[i] = RD4(sc, MCI_RSPR + i * 4);
+ if (mci_debug)
+ printf("RSPR[%d] = %x sr=%x\n", i, cmd->resp[i], sr);
+ }
+ }
+
+ /* If this was a stop command, go handle the various special
+ * conditions (read: bugs) that have to be dealt with following a stop.
+ */
+
+ if (cmd->opcode == MMC_STOP_TRANSMISSION) {
+ at91_mci_stop_done(sc, sr);
+ return;
+ }
+
+ /* If this command can continue to assert BUSY beyond the response then
+ * we need to wait for NOTBUSY before the command is really done.
+ *
+ * Note that this may not work properly on the at91rm9200. It certainly
+ * doesn't work for the STOP command that follows a multi-block write,
+ * so post-stop CMDRDY is handled separately; see the special handling
+ * in at91_mci_stop_done().
+ *
+ * Beside STOP, there are other R1B-type commands that use the busy
+ * signal after CMDRDY: CMD7 (card select), CMD28-29 (write protect),
+ * CMD38 (erase). I haven't tested any of them, but I rather expect
+ * them all to have the same sort of problem with MCI_SR not actually
+ * reflecting the state of the DAT0-line busy indicator. So this code
+ * may need to grow some sort of special handling for them too. (This
+ * just in: CMD7 isn't a problem right now because dev/mmc.c incorrectly
+ * sets the response flags to R1 rather than R1B.)
+ */
+
+ if ((cmd->flags & MMC_RSP_BUSY)) {
+ WR4(sc, MCI_IER, MCI_SR_ERROR | MCI_SR_NOTBUSY);
+ return;
+ }
+
+ /* If there is a data transfer with this command, then...
+ * - If it's a read, we need to wait for ENDRX.
+ * - If it's a write, now is the time to enable the PDC and we need to
+ * wait for BLKE.
+ */
+
+ if (cmd->data) {
+ uint32_t ier;
+ if (cmd->data->flags & MMC_DATA_READ) {
+ ier = MCI_SR_ENDRX;
+ } else {
+ ier = MCI_SR_BLKE;
+ WR4(sc, PDC_PTCR, PDC_PTCR_TXTEN);
+ }
+ WR4(sc, MCI_IER, MCI_SR_ERROR | ier);
+ return;
+ }
+
+ /* If we made it to here, we don't need to wait for anything more for
+ * the current command, move on to the next command (will complete the
+ * request if there is no next command).
+ */
+
+ cmd->error = MMC_ERR_NONE;
+ at91_mci_next_operation(sc);
}
static void
at91_mci_intr(void *arg)
{
struct at91_mci_softc *sc = (struct at91_mci_softc*)arg;
- uint32_t sr;
- int i, done = 0;
- struct mmc_command *cmd;
+ struct mmc_command *cmd = sc->curcmd;
+ uint32_t sr, isr;
AT91_MCI_LOCK(sc);
- sr = RD4(sc, MCI_SR) & RD4(sc, MCI_IMR);
-// printf("i 0x%x\n", sr);
- cmd = sc->curcmd;
- if (sr & MCI_SR_ERROR) {
- // Ignore CRC errors on CMD2 and ACMD47, per relevant standards
- if ((sr & MCI_SR_RCRCE) && (cmd->opcode == MMC_SEND_OP_COND ||
- cmd->opcode == ACMD_SD_SEND_OP_COND))
- cmd->error = MMC_ERR_NONE;
- else if (sr & (MCI_SR_RTOE | MCI_SR_DTOE))
+
+ sr = RD4(sc, MCI_SR);
+ isr = sr & RD4(sc, MCI_IMR);
+
+ if (mci_debug)
+ printf("i 0x%x sr 0x%x\n", isr, sr);
+
+ /* All interrupts are one-shot; disable it now.
+ * The next operation will re-enable whatever interrupts it wants.
+ */
+
+ WR4(sc, MCI_IDR, isr);
+
+ if (isr & MCI_SR_ERROR) {
+ if (isr & (MCI_SR_RTOE | MCI_SR_DTOE))
cmd->error = MMC_ERR_TIMEOUT;
- else if (sr & (MCI_SR_RCRCE | MCI_SR_DCRCE))
+ else if (isr & (MCI_SR_RCRCE | MCI_SR_DCRCE))
cmd->error = MMC_ERR_BADCRC;
- else if (sr & (MCI_SR_OVRE | MCI_SR_UNRE))
+ else if (isr & (MCI_SR_OVRE | MCI_SR_UNRE))
cmd->error = MMC_ERR_FIFO;
else
cmd->error = MMC_ERR_FAILED;
- done = 1;
- if (sc->mapped && cmd->error) {
- bus_dmamap_unload(sc->dmatag, sc->map);
- sc->mapped--;
- }
+ device_printf(sc->dev,
+ "IO error; status MCI_SR = 0x%x cmd opcode = %d\n",
+ sr, cmd->opcode);
+ sc->flags |= PENDING_ERROR;
+ at91_mci_reset(sc);
+ at91_mci_next_operation(sc);
} else {
- if (sr & MCI_SR_TXBUFE) {
+ if (isr & MCI_SR_TXBUFE) {
// printf("TXBUFE\n");
- at91_mci_xmit_done(sc);
}
- if (sr & MCI_SR_RXBUFF) {
+ if (isr & MCI_SR_RXBUFF) {
// printf("RXBUFF\n");
- WR4(sc, MCI_IDR, MCI_SR_RXBUFF);
- WR4(sc, MCI_IER, MCI_SR_CMDRDY);
}
- if (sr & MCI_SR_ENDTX) {
+ if (isr & MCI_SR_ENDTX) {
// printf("ENDTX\n");
}
- if (sr & MCI_SR_ENDRX) {
+ if (isr & MCI_SR_ENDRX) {
// printf("ENDRX\n");
at91_mci_read_done(sc);
}
- if (sr & MCI_SR_NOTBUSY) {
+ if (isr & MCI_SR_NOTBUSY) {
// printf("NOTBUSY\n");
- WR4(sc, MCI_IDR, MCI_SR_NOTBUSY);
- WR4(sc, MCI_IER, MCI_SR_CMDRDY);
+ at91_mci_notbusy(sc);
}
- if (sr & MCI_SR_DTIP) {
+ if (isr & MCI_SR_DTIP) {
// printf("Data transfer in progress\n");
}
- if (sr & MCI_SR_BLKE) {
+ if (isr & MCI_SR_BLKE) {
// printf("Block transfer end\n");
+ at91_mci_write_done(sc, sr);
}
- if (sr & MCI_SR_TXRDY) {
+ if (isr & MCI_SR_TXRDY) {
// printf("Ready to transmit\n");
}
- if (sr & MCI_SR_RXRDY) {
+ if (isr & MCI_SR_RXRDY) {
// printf("Ready to receive\n");
}
- if (sr & MCI_SR_CMDRDY) {
+ if (isr & MCI_SR_CMDRDY) {
// printf("Command ready\n");
- done = 1;
- cmd->error = MMC_ERR_NONE;
- }
- }
- if (done) {
- WR4(sc, MCI_IDR, 0xffffffff);
- if (cmd != NULL && (cmd->flags & MMC_RSP_PRESENT)) {
- for (i = 0; i < ((cmd->flags & MMC_RSP_136) ? 4 : 1);
- i++) {
- cmd->resp[i] = RD4(sc, MCI_RSPR + i * 4);
-// printf("RSPR[%d] = %x\n", i, cmd->resp[i]);
- }
+ at91_mci_cmdrdy(sc, sr);
}
- at91_mci_start(sc);
}
AT91_MCI_UNLOCK(sc);
}
@@ -703,7 +1003,7 @@
*(int *)result = sc->host.caps;
break;
case MMCBR_IVAR_MAX_DATA:
- *(int *)result = 1;
+ *(int *)result = AT91_MCI_MAX_BLOCKS;
break;
}
return (0);
--- patch-arm-at91_mci-for-multiblock ends here ---
>Release-Note:
>Audit-Trail:
>Unformatted:
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