On 08/06/2012 03:15 PM, Peter Maydell wrote:
On 6 August 2012 04:25, Peter A. G. Crosthwaite
<peter.crosthwa...@petalogix.com> wrote:
From: Igor Mitsyanko <i.mitsya...@samsung.com>
Device model for standard SD Host Controller Interface (SDHCI) compliant with
version 2.00 of SD association specification.
+typedef struct ADMADescr {
+ target_phys_addr_t addr;
+ uint16_t length;
+ uint8_t attr;
+ uint8_t incr;
+} ADMADescr;
+
+static void get_adma_description(SDHCIState *s, ADMADescr *dscr)
+{
+ uint32_t adma1 = 0;
+ uint64_t adma2 = 0;
+ target_phys_addr_t entry_addr = (target_phys_addr_t)s->admasysaddr;
+
+ switch (SDHC_DMA_TYPE(s->hostctl)) {
+ case SDHC_CTRL_ADMA2_32:
+ cpu_physical_memory_read(entry_addr, (uint8_t *)&adma2, sizeof(adma2));
+ dscr->addr = (target_phys_addr_t)((adma2 >> 32) & 0xfffffffc);
+ dscr->length = (uint16_t)((adma2 >> 16) & 0xFFFF);
+ dscr->attr = (uint8_t)(adma2 & 0x3F);
+ dscr->incr = 8;
+ break;
+ case SDHC_CTRL_ADMA1_32:
+ cpu_physical_memory_read(entry_addr, (uint8_t *)&adma1, sizeof(adma1));
+ dscr->addr = (target_phys_addr_t)(adma1 & 0xFFFFF000);
+ dscr->attr = (uint8_t)(adma1 & 0x3F);
+ dscr->incr = 4;
+ if ((dscr->attr & SDHC_ADMA_ATTR_ACT_MASK) == SDHC_ADMA_ATTR_SET_LEN) {
+ dscr->length = (uint16_t)((adma1 >> 12) & 0xFFFF);
+ } else {
+ dscr->length = 4096;
+ }
+ break;
+ case SDHC_CTRL_ADMA2_64:
+ cpu_physical_memory_read(entry_addr, (uint8_t *)(&dscr->attr), 1);
+ cpu_physical_memory_read(entry_addr + 2, (uint8_t *)(&dscr->length),
2);
+ cpu_physical_memory_read(entry_addr + 4, (uint8_t *)(&dscr->addr), 8);
+ dscr->attr &= 0xfffffff8;
+ dscr->incr = 12;
+ break;
+ }
+}
+
+/* Advanced DMA data transfer */
+static void sdhci_start_adma(SDHCIState *s)
+{
+ unsigned int n, begin, length;
+ const uint16_t block_size = s->blksize & 0x0fff;
+ ADMADescr dscr;
+ s->admaerr &= ~SDHC_ADMAERR_LENGTH_MISMATCH;
+
+ while (1) {
+ get_adma_description(s, &dscr);
+ DPRINT_L2("ADMA loop: addr=" TARGET_FMT_plx ", len=%d, attr=%x\n",
+ dscr.addr, dscr.length, dscr.attr);
+
+ if ((dscr.attr & SDHC_ADMA_ATTR_VALID) == 0) {
+ /* Indicate that error occurred in ST_FDS state */
+ s->admaerr &= ~SDHC_ADMAERR_STATE_MASK;
+ s->admaerr |= SDHC_ADMAERR_STATE_ST_FDS;
+
+ /* Generate ADMA error interrupt */
+ if (s->errintstsen & SDHC_EISEN_ADMAERR) {
+ s->errintsts |= SDHC_EIS_ADMAERR;
+ s->norintsts |= SDHC_NIS_ERR;
+ }
+
+ sdhci_update_irq(s);
+ break;
+ }
+
+ length = dscr.length ? dscr.length : 65536;
+
+ switch (dscr.attr & SDHC_ADMA_ATTR_ACT_MASK) {
+ case SDHC_ADMA_ATTR_ACT_TRAN: /* data transfer */
+
+ if (s->trnmod & SDHC_TRNS_READ) {
+ while (length) {
+ if (s->data_count == 0) {
+ for (n = 0; n < block_size; n++) {
+ s->fifo_buffer[n] = sd_read_data(s->card);
+ }
+ }
+ begin = s->data_count;
+ if ((length + begin) < block_size) {
+ s->data_count = length + begin;
+ length = 0;
+ } else {
+ s->data_count = block_size;
+ length -= block_size - begin;
+ }
+ cpu_physical_memory_write(dscr.addr,
&s->fifo_buffer[begin],
+ s->data_count - begin);
+ dscr.addr += s->data_count - begin;
+ if (s->data_count == block_size) {
+ s->data_count = 0;
+ if (s->trnmod & SDHC_TRNS_BLK_CNT_EN) {
+ s->blkcnt--;
+ if (s->blkcnt == 0) {
+ break;
+ }
+ }
+ }
+ }
+ } else {
+ while (length) {
+ begin = s->data_count;
+ if ((length + begin) < block_size) {
+ s->data_count = length + begin;
+ length = 0;
+ } else {
+ s->data_count = block_size;
+ length -= block_size - begin;
+ }
+ cpu_physical_memory_read(dscr.addr,
+ &s->fifo_buffer[begin], s->data_count);
+ dscr.addr += s->data_count - begin;
+ if (s->data_count == block_size) {
+ for (n = 0; n < block_size; n++) {
+ sd_write_data(s->card, s->fifo_buffer[n]);
+ }
+ s->data_count = 0;
+ if (s->trnmod & SDHC_TRNS_BLK_CNT_EN) {
+ s->blkcnt--;
+ if (s->blkcnt == 0) {
+ break;
+ }
+ }
+ }
+ }
+ }
+ s->admasysaddr += dscr.incr;
+ break;
+ case SDHC_ADMA_ATTR_ACT_LINK: /* link to next descriptor table */
+ s->admasysaddr = dscr.addr;
+ DPRINT_L1("ADMA link: admasysaddr=0x%lx\n", s->admasysaddr);
+ break;
+ default:
+ s->admasysaddr += dscr.incr;
+ break;
+ }
+
+ /* ADMA transfer terminates if blkcnt == 0 or by END attribute */
+ if (((s->trnmod & SDHC_TRNS_BLK_CNT_EN) &&
+ (s->blkcnt == 0)) || (dscr.attr & SDHC_ADMA_ATTR_END)) {
+ DPRINT_L2("ADMA transfer completed\n");
+ if (length || ((dscr.attr & SDHC_ADMA_ATTR_END) &&
+ (s->trnmod & SDHC_TRNS_BLK_CNT_EN) &&
+ s->blkcnt != 0) || ((s->trnmod & SDHC_TRNS_BLK_CNT_EN) &&
+ s->blkcnt == 0 && (dscr.attr & SDHC_ADMA_ATTR_END) == 0)) {
+ ERRPRINT("SD/MMC host ADMA length mismatch\n");
+ s->admaerr |= SDHC_ADMAERR_LENGTH_MISMATCH |
+ SDHC_ADMAERR_STATE_ST_TFR;
+ if (s->errintstsen & SDHC_EISEN_ADMAERR) {
+ ERRPRINT("Set ADMA error flag\n");
+ s->errintsts |= SDHC_EIS_ADMAERR;
+ s->norintsts |= SDHC_NIS_ERR;
+ }
+
+ sdhci_update_irq(s);
+ }
+ SDHCI_GET_CLASS(s)->end_data_transfer(s);
+ break;
+ }
+
+ if (dscr.attr & SDHC_ADMA_ATTR_INT) {
+ DPRINT_L1("ADMA interrupt: admasysaddr=0x%lx\n", s->admasysaddr);
+ if (s->norintstsen & SDHC_NISEN_DMA) {
+ s->norintsts |= SDHC_NIS_DMA;
+ }
+
+ sdhci_update_irq(s);
+ break;
+ }
+ }
+}
So I think the guest can make this loop never terminate if it sets up
a loop of ACT_LINK descriptors, right? I don't know how we should
handle this but I'm pretty sure "make qemu sit there forever not responding
to anything and not resettable" isn't it.
-- PMM
That could only happen if guest would do this on purpose, but I see your
point. There's no way for us to tell if SD card read/write succeeded or
not, so I think the only way to to this is to suspend transfer after
some reasonable amount of loops and resume it by qemu_timer, giving CPU
time to do something useful.
I've never seen long ADMA loops, so it wouldn't reflect on performance
in any way.
