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bcm2835-sdhost: Further improve overclock back-off
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@gohai
Phil Elwell authored and gohai committed Jul 29, 2015
1 parent 9268e6b commit c08aff0
Showing 1 changed file with 78 additions and 66 deletions.
144 changes: 78 additions & 66 deletions drivers/mmc/host/bcm2835-sdhost.c
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Original file line number Diff line number Diff line change
Expand Up @@ -161,8 +161,6 @@ struct bcm2835_host {

unsigned int use_busy:1; /* Wait for busy interrupt */

unsigned int reduce_overclock:1; /* ...at the next opportunity */

unsigned int debug:1; /* Enable debug output */

u32 thread_isr;
Expand Down Expand Up @@ -466,36 +464,25 @@ static void bcm2835_sdhost_dma_complete(void *param)
spin_unlock_irqrestore(&host->lock, flags);
}

static bool data_transfer_wait(struct bcm2835_host *host, const char *caller)
static bool data_transfer_wait(struct bcm2835_host *host)
{
unsigned long timeout = 1000000;
u32 hsts;
while (timeout)
{
hsts = bcm2835_sdhost_read(host, SDHSTS);
if (hsts & (SDHSTS_TRANSFER_ERROR_MASK |
SDHSTS_DATA_FLAG)) {
bcm2835_sdhost_write(host, SDHSTS_TRANSFER_ERROR_MASK,
SDHSTS);
u32 sdhsts = bcm2835_sdhost_read(host, SDHSTS);
if (sdhsts & SDHSTS_DATA_FLAG) {
bcm2835_sdhost_write(host, SDHSTS_DATA_FLAG, SDHSTS);
break;
}
timeout--;
}

if (hsts & (SDHSTS_CRC16_ERROR |
SDHSTS_CRC7_ERROR |
SDHSTS_FIFO_ERROR)) {
pr_err("%s: data error in %s - HSTS %x\n",
mmc_hostname(host->mmc), caller, hsts);
host->data->error = -EILSEQ;
return false;
} else if ((timeout == 0) ||
(hsts & (SDHSTS_CMD_TIME_OUT |
SDHSTS_REW_TIME_OUT))) {
pr_err("%s: timeout in %s - HSTS %x\n",
mmc_hostname(host->mmc), caller, hsts);
host->data->error = -ETIMEDOUT;
return false;
if (timeout == 0) {
pr_err("%s: Data %s timeout\n",
mmc_hostname(host->mmc),
(host->data->flags & MMC_DATA_READ) ? "read" : "write");
bcm2835_sdhost_dumpregs(host);
host->data->error = -ETIMEDOUT;
return false;
}
return true;
}
Expand Down Expand Up @@ -523,7 +510,7 @@ static void bcm2835_sdhost_read_block_pio(struct bcm2835_host *host)
buf = (u32 *)host->sg_miter.addr;

while (len) {
if (!data_transfer_wait(host, "read_block_pio"))
if (!data_transfer_wait(host))
break;

*(buf++) = bcm2835_sdhost_read(host, SDDATA);
Expand Down Expand Up @@ -562,7 +549,7 @@ static void bcm2835_sdhost_write_block_pio(struct bcm2835_host *host)
buf = host->sg_miter.addr;

while (len) {
if (!data_transfer_wait(host, "write_block_pio"))
if (!data_transfer_wait(host))
break;

bcm2835_sdhost_write(host, *(buf++), SDDATA);
Expand All @@ -581,13 +568,33 @@ static void bcm2835_sdhost_write_block_pio(struct bcm2835_host *host)

static void bcm2835_sdhost_transfer_pio(struct bcm2835_host *host)
{
u32 sdhsts;
bool is_read;
BUG_ON(!host->data);

if (host->data->flags & MMC_DATA_READ) {
is_read = (host->data->flags & MMC_DATA_READ) != 0;
if (is_read)
bcm2835_sdhost_read_block_pio(host);
} else {
else
bcm2835_sdhost_write_block_pio(host);

sdhsts = bcm2835_sdhost_read(host, SDHSTS);
if (sdhsts & (SDHSTS_CRC16_ERROR |
SDHSTS_CRC7_ERROR |
SDHSTS_FIFO_ERROR)) {
pr_err("%s: %s transfer error - HSTS %x\n",
mmc_hostname(host->mmc),
is_read ? "read" : "write",
sdhsts);
host->data->error = -EILSEQ;
} else if ((sdhsts & (SDHSTS_CMD_TIME_OUT |
SDHSTS_REW_TIME_OUT))) {
pr_err("%s: %s timeout error - HSTS %x\n",
mmc_hostname(host->mmc),
is_read ? "read" : "write",
sdhsts);
host->data->error = -ETIMEDOUT;
} else if (!is_read && !host->data->error) {
/* Start a timer in case a transfer error occurs because
there is no error interrupt */
mod_timer(&host->pio_timer, jiffies + host->pio_timeout);
Expand Down Expand Up @@ -701,8 +708,9 @@ static void bcm2835_sdhost_prepare_data(struct bcm2835_host *host, struct mmc_co

void bcm2835_sdhost_send_command(struct bcm2835_host *host, struct mmc_command *cmd)
{
u32 sdcmd;
u32 sdcmd, sdhsts;
unsigned long timeout;
int delay;

WARN_ON(host->cmd);

Expand All @@ -719,8 +727,8 @@ void bcm2835_sdhost_send_command(struct bcm2835_host *host, struct mmc_command *
mmc_hostname(host->mmc),
cmd->opcode, cmd->arg, cmd->flags);

/* Wait max 10 ms */
timeout = 1000;
/* Wait max 100 ms */
timeout = 10000;

while (bcm2835_sdhost_read(host, SDCMD) & SDCMD_NEW_FLAG) {
if (timeout == 0) {
Expand All @@ -735,8 +743,9 @@ void bcm2835_sdhost_send_command(struct bcm2835_host *host, struct mmc_command *
udelay(10);
}

if ((1000-timeout)/100 > 1 && (1000-timeout)/100 > host->max_delay) {
host->max_delay = (1000-timeout)/100;
delay = (10000 - timeout)/100;
if (delay > host->max_delay) {
host->max_delay = delay;
pr_warning("%s: controller hung for %d ms\n",
mmc_hostname(host->mmc),
host->max_delay);
Expand All @@ -751,6 +760,11 @@ void bcm2835_sdhost_send_command(struct bcm2835_host *host, struct mmc_command *

host->cmd = cmd;

/* Clear any error flags */
sdhsts = bcm2835_sdhost_read(host, SDHSTS);
if (sdhsts & SDHSTS_ERROR_MASK)
bcm2835_sdhost_write(host, sdhsts, SDHSTS);

bcm2835_sdhost_prepare_data(host, cmd);

bcm2835_sdhost_write(host, cmd->arg, SDARG);
Expand Down Expand Up @@ -876,7 +890,7 @@ static void bcm2835_sdhost_transfer_complete(struct bcm2835_host *host)
static void bcm2835_sdhost_finish_command(struct bcm2835_host *host)
{
u32 sdcmd;
int timeout = 1000;
unsigned long timeout;
#ifdef DEBUG
struct timeval before, after;
int timediff = 0;
Expand All @@ -889,6 +903,8 @@ static void bcm2835_sdhost_finish_command(struct bcm2835_host *host)
#ifdef DEBUG
do_gettimeofday(&before);
#endif
/* Wait max 100 ms */
timeout = 10000;
for (sdcmd = bcm2835_sdhost_read(host, SDCMD);
(sdcmd & SDCMD_NEW_FLAG) && timeout;
timeout--) {
Expand Down Expand Up @@ -1049,9 +1065,9 @@ static void bcm2835_sdhost_pio_timeout(unsigned long data)
spin_lock_irqsave(&host->lock, flags);

if (host->data) {
u32 hsts = bcm2835_sdhost_read(host, SDHSTS);
u32 sdhsts = bcm2835_sdhost_read(host, SDHSTS);

if (hsts & SDHSTS_REW_TIME_OUT) {
if (sdhsts & SDHSTS_REW_TIME_OUT) {
pr_err("%s: transfer timeout\n",
mmc_hostname(host->mmc));
if (host->debug)
Expand Down Expand Up @@ -1380,19 +1396,10 @@ void bcm2835_sdhost_set_clock(struct bcm2835_host *host, unsigned int clock)
if (host->debug)
pr_info("%s: set_clock(%d)\n", mmc_hostname(host->mmc), clock);

if ((clock == 0) && host->reduce_overclock) {
/* This is a reset following data corruption - reduce any
overclock */
host->reduce_overclock = 0;
if (host->overclock_50 > 50) {
pr_warn("%s: reducing overclock due to errors\n",
mmc_hostname(host->mmc));
host->overclock_50--;
}
}

if (host->overclock_50 && (clock == 50*MHZ))
if ((host->overclock_50 > 50) &&
(clock == 50*MHZ)) {
clock = host->overclock_50 * MHZ + (MHZ - 1);
}

/* The SDCDIV register has 11 bits, and holds (div - 2).
But in data mode the max is 50MHz wihout a minimum, and only the
Expand Down Expand Up @@ -1450,11 +1457,12 @@ void bcm2835_sdhost_set_clock(struct bcm2835_host *host, unsigned int clock)
host->overclock = clock;
}
}
else if ((clock == 50 * MHZ) && host->overclock)
else if (host->overclock)
{
pr_warn("%s: cancelling overclock\n",
mmc_hostname(host->mmc));
host->overclock = 0;
if (clock == 50 * MHZ)
pr_warn("%s: cancelling overclock\n",
mmc_hostname(host->mmc));
}

host->cdiv = div;
Expand Down Expand Up @@ -1492,6 +1500,14 @@ static void bcm2835_sdhost_request(struct mmc_host *mmc, struct mmc_request *mrq
cmd->opcode, cmd->arg, cmd->flags);
}

/* Reset the error statuses in case this is a retry */
if (mrq->cmd)
mrq->cmd->error = 0;
if (mrq->data)
mrq->data->error = 0;
if (mrq->stop)
mrq->stop->error = 0;

if (mrq->data && !is_power_of_2(mrq->data->blksz)) {
pr_err("%s: unsupported block size (%d bytes)\n",
mmc_hostname(mmc), mrq->data->blksz);
Expand Down Expand Up @@ -1613,21 +1629,16 @@ static void bcm2835_sdhost_tasklet_finish(unsigned long param)

/* Drop the overclock after any data corruption, or after any
error overclocked */
if (mrq->data && (mrq->data->error == -EILSEQ))
host->reduce_overclock = 1;
else if (host->overclock) {
/* Convert timeout errors while overclocked to data errors,
because the system recovers better. */
if (mrq->cmd && mrq->cmd->error) {
host->reduce_overclock = 1;
if (mrq->cmd->error == -ETIMEDOUT)
mrq->cmd->error = -EILSEQ;
}

if (mrq->data && mrq->data->error) {
host->reduce_overclock = 1;
if (mrq->data->error == -ETIMEDOUT)
mrq->data->error = -EILSEQ;
if (host->overclock) {
if ((mrq->cmd && mrq->cmd->error) ||
(mrq->data && mrq->data->error) ||
(mrq->stop && mrq->stop->error)) {
host->overclock_50--;
pr_warn("%s: reducing overclock due to errors\n",
mmc_hostname(host->mmc));
bcm2835_sdhost_set_clock(host,50*MHZ);
mrq->cmd->error = -EILSEQ;
mrq->cmd->retries = 1;
}
}

Expand Down Expand Up @@ -1769,6 +1780,7 @@ static int bcm2835_sdhost_probe(struct platform_device *pdev)
host = mmc_priv(mmc);
host->mmc = mmc;
host->pio_timeout = msecs_to_jiffies(500);
host->max_delay = 1; /* Warn if over 1ms */
spin_lock_init(&host->lock);

iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
Expand Down

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