Commit fd450fed authored by Jarkko Lavinen's avatar Jarkko Lavinen Committed by Tony Lindgren

MMC: OMAP: Lazy clock shutdown

MMCA spec says the mmc clock should be kept running for at least
8 cycles after the last RW request. Ensure this with lazy clock
disable after a request, or with an explicit delay before
switching a slot.
Signed-off-by: default avatarJarkko Lavinen <jarkko.lavinen@nokia.com>
Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
parent c27f39a9
...@@ -163,9 +163,38 @@ struct mmc_omap_host { ...@@ -163,9 +163,38 @@ struct mmc_omap_host {
wait_queue_head_t slot_wq; wait_queue_head_t slot_wq;
int nr_slots; int nr_slots;
struct timer_list clk_timer;
spinlock_t clk_lock; /* for changing enabled state */
unsigned int fclk_enabled:1;
struct omap_mmc_platform_data *pdata; struct omap_mmc_platform_data *pdata;
}; };
void mmc_omap_fclk_offdelay(struct mmc_omap_slot *slot)
{
unsigned long tick_ns;
if (slot != NULL && slot->host->fclk_enabled && slot->fclk_freq > 0) {
tick_ns = (1000000000 + slot->fclk_freq - 1) / slot->fclk_freq;
ndelay(8 * tick_ns);
}
}
void mmc_omap_fclk_enable(struct mmc_omap_host *host, unsigned int enable)
{
unsigned long flags;
spin_lock_irqsave(&host->clk_lock, flags);
if (host->fclk_enabled != enable) {
host->fclk_enabled = enable;
if (enable)
clk_enable(host->fclk);
else
clk_disable(host->fclk);
}
spin_unlock_irqrestore(&host->clk_lock, flags);
}
static void mmc_omap_select_slot(struct mmc_omap_slot *slot, int claimed) static void mmc_omap_select_slot(struct mmc_omap_slot *slot, int claimed)
{ {
struct mmc_omap_host *host = slot->host; struct mmc_omap_host *host = slot->host;
...@@ -182,32 +211,49 @@ static void mmc_omap_select_slot(struct mmc_omap_slot *slot, int claimed) ...@@ -182,32 +211,49 @@ static void mmc_omap_select_slot(struct mmc_omap_slot *slot, int claimed)
host->mmc = slot->mmc; host->mmc = slot->mmc;
spin_unlock_irqrestore(&host->slot_lock, flags); spin_unlock_irqrestore(&host->slot_lock, flags);
no_claim: no_claim:
clk_enable(host->fclk); del_timer(&host->clk_timer);
if (host->current_slot != slot || !claimed)
mmc_omap_fclk_offdelay(host->current_slot);
if (host->current_slot != slot) { if (host->current_slot != slot) {
OMAP_MMC_WRITE(host, CON, slot->saved_con & 0xFC00);
if (host->pdata->switch_slot != NULL) if (host->pdata->switch_slot != NULL)
host->pdata->switch_slot(mmc_dev(slot->mmc), slot->id); host->pdata->switch_slot(mmc_dev(slot->mmc), slot->id);
host->current_slot = slot; host->current_slot = slot;
} }
/* Doing the dummy read here seems to work around some bug if (claimed) {
* at least in OMAP24xx silicon where the command would not mmc_omap_fclk_enable(host, 1);
* start after writing the CMD register. Sigh. */
OMAP_MMC_READ(host, CON); /* Doing the dummy read here seems to work around some bug
* at least in OMAP24xx silicon where the command would not
* start after writing the CMD register. Sigh. */
OMAP_MMC_READ(host, CON);
OMAP_MMC_WRITE(host, CON, slot->saved_con); OMAP_MMC_WRITE(host, CON, slot->saved_con);
} else
mmc_omap_fclk_enable(host, 0);
} }
static void mmc_omap_start_request(struct mmc_omap_host *host, static void mmc_omap_start_request(struct mmc_omap_host *host,
struct mmc_request *req); struct mmc_request *req);
static void mmc_omap_release_slot(struct mmc_omap_slot *slot) static void mmc_omap_release_slot(struct mmc_omap_slot *slot, int clk_enabled)
{ {
struct mmc_omap_host *host = slot->host; struct mmc_omap_host *host = slot->host;
unsigned long flags; unsigned long flags;
int i; int i;
BUG_ON(slot == NULL || host->mmc == NULL); BUG_ON(slot == NULL || host->mmc == NULL);
clk_disable(host->fclk);
if (clk_enabled)
/* Keeps clock running for at least 8 cycles on valid freq */
mod_timer(&host->clk_timer, jiffies + HZ/10);
else {
del_timer(&host->clk_timer);
mmc_omap_fclk_offdelay(slot);
mmc_omap_fclk_enable(host, 0);
}
spin_lock_irqsave(&host->slot_lock, flags); spin_lock_irqsave(&host->slot_lock, flags);
/* Check for any pending requests */ /* Check for any pending requests */
...@@ -388,7 +434,7 @@ mmc_omap_xfer_done(struct mmc_omap_host *host, struct mmc_data *data) ...@@ -388,7 +434,7 @@ mmc_omap_xfer_done(struct mmc_omap_host *host, struct mmc_data *data)
host->mrq = NULL; host->mrq = NULL;
mmc = host->mmc; mmc = host->mmc;
mmc_omap_release_slot(host->current_slot); mmc_omap_release_slot(host->current_slot, 1);
mmc_request_done(mmc, data->mrq); mmc_request_done(mmc, data->mrq);
return; return;
} }
...@@ -522,7 +568,7 @@ mmc_omap_cmd_done(struct mmc_omap_host *host, struct mmc_command *cmd) ...@@ -522,7 +568,7 @@ mmc_omap_cmd_done(struct mmc_omap_host *host, struct mmc_command *cmd)
mmc_omap_abort_xfer(host, host->data); mmc_omap_abort_xfer(host, host->data);
host->mrq = NULL; host->mrq = NULL;
mmc = host->mmc; mmc = host->mmc;
mmc_omap_release_slot(host->current_slot); mmc_omap_release_slot(host->current_slot, 1);
mmc_request_done(mmc, cmd->mrq); mmc_request_done(mmc, cmd->mrq);
} }
} }
...@@ -553,7 +599,7 @@ static void mmc_omap_abort_command(struct work_struct *work) ...@@ -553,7 +599,7 @@ static void mmc_omap_abort_command(struct work_struct *work)
host->mrq = NULL; host->mrq = NULL;
mmc = host->mmc; mmc = host->mmc;
mmc_omap_release_slot(host->current_slot); mmc_omap_release_slot(host->current_slot, 1);
mmc_request_done(mmc, cmd->mrq); mmc_request_done(mmc, cmd->mrq);
} else } else
mmc_omap_cmd_done(host, host->cmd); mmc_omap_cmd_done(host, host->cmd);
...@@ -591,6 +637,14 @@ mmc_omap_sg_to_buf(struct mmc_omap_host *host) ...@@ -591,6 +637,14 @@ mmc_omap_sg_to_buf(struct mmc_omap_host *host)
host->buffer_bytes_left = host->total_bytes_left; host->buffer_bytes_left = host->total_bytes_left;
} }
static void
mmc_omap_clk_timer(unsigned long data)
{
struct mmc_omap_host *host = (struct mmc_omap_host *) data;
mmc_omap_fclk_enable(host, 0);
}
/* PIO only */ /* PIO only */
static void static void
mmc_omap_xfer_data(struct mmc_omap_host *host, int write) mmc_omap_xfer_data(struct mmc_omap_host *host, int write)
...@@ -1167,14 +1221,16 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) ...@@ -1167,14 +1221,16 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
struct mmc_omap_slot *slot = mmc_priv(mmc); struct mmc_omap_slot *slot = mmc_priv(mmc);
struct mmc_omap_host *host = slot->host; struct mmc_omap_host *host = slot->host;
int i, dsor; int i, dsor;
int clk_enabled;
dsor = mmc_omap_calc_divisor(mmc, ios);
mmc_omap_select_slot(slot, 0); mmc_omap_select_slot(slot, 0);
dsor = mmc_omap_calc_divisor(mmc, ios);
if (ios->vdd != slot->vdd) if (ios->vdd != slot->vdd)
slot->vdd = ios->vdd; slot->vdd = ios->vdd;
clk_enabled = 0;
switch (ios->power_mode) { switch (ios->power_mode) {
case MMC_POWER_OFF: case MMC_POWER_OFF:
mmc_omap_set_power(slot, 0, ios->vdd); mmc_omap_set_power(slot, 0, ios->vdd);
...@@ -1184,6 +1240,8 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) ...@@ -1184,6 +1240,8 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
mmc_omap_set_power(slot, 1, ios->vdd); mmc_omap_set_power(slot, 1, ios->vdd);
goto exit; goto exit;
case MMC_POWER_ON: case MMC_POWER_ON:
mmc_omap_fclk_enable(host, 1);
clk_enabled = 1;
dsor |= 1 << 11; dsor |= 1 << 11;
break; break;
} }
...@@ -1212,7 +1270,7 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) ...@@ -1212,7 +1270,7 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
} }
exit: exit:
mmc_omap_release_slot(slot); mmc_omap_release_slot(slot, clk_enabled);
} }
static int mmc_omap_get_ro(struct mmc_host *mmc) static int mmc_omap_get_ro(struct mmc_host *mmc)
...@@ -1375,6 +1433,9 @@ static int __init mmc_omap_probe(struct platform_device *pdev) ...@@ -1375,6 +1433,9 @@ static int __init mmc_omap_probe(struct platform_device *pdev)
setup_timer(&host->cmd_abort_timer, mmc_omap_cmd_timer, setup_timer(&host->cmd_abort_timer, mmc_omap_cmd_timer,
(unsigned long) host); (unsigned long) host);
spin_lock_init(&host->clk_lock);
setup_timer(&host->clk_timer, mmc_omap_clk_timer, (unsigned long) host);
spin_lock_init(&host->dma_lock); spin_lock_init(&host->dma_lock);
setup_timer(&host->dma_timer, mmc_omap_dma_timer, (unsigned long) host); setup_timer(&host->dma_timer, mmc_omap_dma_timer, (unsigned long) host);
spin_lock_init(&host->slot_lock); spin_lock_init(&host->slot_lock);
......
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