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* [PATCH 16/18] MMC: OMAP: Lazy clock shutdown
@ 2008-01-28 19:08 Carlos Aguiar
  0 siblings, 0 replies; 3+ messages in thread
From: Carlos Aguiar @ 2008-01-28 19:08 UTC (permalink / raw)
  To: Pierre Ossman; +Cc: Tony Lindgren, linux-kernel

From: Jarkko Lavinen <jarkko.lavinen@nokia.com>

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: Jarkko Lavinen <jarkko.lavinen@nokia.com>
---
 drivers/mmc/host/omap.c |   89 +++++++++++++++++++++++++++++++++++++++-------
 1 files changed, 75 insertions(+), 14 deletions(-)

diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c
index df15d96..1d8bb69 100644
--- a/drivers/mmc/host/omap.c
+++ b/drivers/mmc/host/omap.c
@@ -162,9 +162,38 @@ struct mmc_omap_host {
 	wait_queue_head_t       slot_wq;
 	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;
 };
 
+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)
 {
 	struct mmc_omap_host *host = slot->host;
@@ -181,32 +210,49 @@ static void mmc_omap_select_slot(struct mmc_omap_slot *slot, int claimed)
 	host->mmc = slot->mmc;
 	spin_unlock_irqrestore(&host->slot_lock, flags);
 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) {
+		OMAP_MMC_WRITE(host, CON, slot->saved_con & 0xFC00);
 		if (host->pdata->switch_slot != NULL)
 			host->pdata->switch_slot(mmc_dev(slot->mmc), slot->id);
 		host->current_slot = slot;
 	}
 
-	/* 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);
+	if (claimed) {
+		mmc_omap_fclk_enable(host, 1);
+
+		/* 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,
 				   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;
 	unsigned long flags;
 	int i;
 
 	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);
 	/* Check for any pending requests */
@@ -388,7 +434,7 @@ mmc_omap_xfer_done(struct mmc_omap_host *host, struct mmc_data *data)
 
 		host->mrq = NULL;
 		mmc = host->mmc;
-		mmc_omap_release_slot(host->current_slot);
+		mmc_omap_release_slot(host->current_slot, 1);
 		mmc_request_done(mmc, data->mrq);
 		return;
 	}
@@ -522,7 +568,7 @@ mmc_omap_cmd_done(struct mmc_omap_host *host, struct mmc_command *cmd)
 			mmc_omap_abort_xfer(host, host->data);
 		host->mrq = NULL;
 		mmc = host->mmc;
-		mmc_omap_release_slot(host->current_slot);
+		mmc_omap_release_slot(host->current_slot, 1);
 		mmc_request_done(mmc, cmd->mrq);
 	}
 }
@@ -553,7 +599,7 @@ static void mmc_omap_abort_command(struct work_struct *work)
 
 		host->mrq = NULL;
 		mmc = host->mmc;
-		mmc_omap_release_slot(host->current_slot);
+		mmc_omap_release_slot(host->current_slot, 1);
 		mmc_request_done(mmc, cmd->mrq);
 	} else
 		mmc_omap_cmd_done(host, host->cmd);
@@ -591,6 +637,14 @@ mmc_omap_sg_to_buf(struct mmc_omap_host *host)
 		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 */
 static void
 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)
 	struct mmc_omap_slot *slot = mmc_priv(mmc);
 	struct mmc_omap_host *host = slot->host;
 	int i, dsor;
-
-	dsor = mmc_omap_calc_divisor(mmc, ios);
+	int clk_enabled;
 
 	mmc_omap_select_slot(slot, 0);
 
+	dsor = mmc_omap_calc_divisor(mmc, ios);
+
 	if (ios->vdd != slot->vdd)
 		slot->vdd = ios->vdd;
 
+	clk_enabled = 0;
 	switch (ios->power_mode) {
 	case MMC_POWER_OFF:
 		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)
 		mmc_omap_set_power(slot, 1, ios->vdd);
 		goto exit;
 	case MMC_POWER_ON:
+		mmc_omap_fclk_enable(host, 1);
+		clk_enabled = 1;
 		dsor |= 1 << 11;
 		break;
 	}
@@ -1212,7 +1270,7 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 	}
 
 exit:
-	mmc_omap_release_slot(slot);
+	mmc_omap_release_slot(slot, clk_enabled);
 }
 
 static int mmc_omap_get_ro(struct mmc_host *mmc)
@@ -1375,6 +1433,9 @@ static int __init mmc_omap_probe(struct platform_device *pdev)
 	setup_timer(&host->cmd_abort_timer, mmc_omap_cmd_timer,
 		    (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);
 	setup_timer(&host->dma_timer, mmc_omap_dma_timer, (unsigned long) host);
 	spin_lock_init(&host->slot_lock);
-- 1.5.3.GIT


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* [PATCH 00/18] MMC: OMAP: Sync MMC OMAP driver with mainline tree
@ 2008-03-14 19:35 Carlos Aguiar
  2008-03-24 12:26 ` Pierre Ossman
  0 siblings, 1 reply; 3+ messages in thread
From: Carlos Aguiar @ 2008-03-14 19:35 UTC (permalink / raw)
  To: Pierre Ossman; +Cc: Tony Lindgren, linux-kernel

Hi Pierre, Tony and folks,

The new version of the patch series that follows is a synchronization
of MMC OMAP driver from Linux-OMAP tree into mainline tree.

Improvements and corrections are based on comments from Pierre Ossman and 
Roel Kluin, from LKML.

Just to remind you, basically it brings MMC multislot support for OMAP boards 
with one slot (like H2 1611, H3 1710) or two slots (like H4 2420 and N800).
Others boards supported by such feature are: N770, Siemens SX1 and Apollon.

BR,

Carlos.

-- 
Carlos Eduardo Aguiar
Nokia Institute of Technology - INdT
Open Source Mobile Research Center - OSMRC - Manaus
Core Team
Phone: +55 92 2126-1079
Mobile: +55 92 8127-1797
E-mail: carlos.aguiar@indt.org.br


^ permalink raw reply	[flat|nested] 3+ messages in thread
* [PATCH 16/18] MMC: OMAP: Lazy clock shutdown
@ 2008-03-14 19:36 Carlos Aguiar
  0 siblings, 0 replies; 3+ messages in thread
From: Carlos Aguiar @ 2008-03-14 19:36 UTC (permalink / raw)
  To: Pierre Ossman; +Cc: Tony Lindgren, linux-kernel

From: Jarkko Lavinen <jarkko.lavinen@nokia.com>

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: Jarkko Lavinen <jarkko.lavinen@nokia.com>
---
 drivers/mmc/host/omap.c |   89 +++++++++++++++++++++++++++++++++++++++-------
 1 files changed, 75 insertions(+), 14 deletions(-)

diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c
index 43719ae..719c93d 100644
--- a/drivers/mmc/host/omap.c
+++ b/drivers/mmc/host/omap.c
@@ -161,9 +161,38 @@ struct mmc_omap_host {
 	wait_queue_head_t       slot_wq;
 	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;
 };
 
+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)
 {
 	struct mmc_omap_host *host = slot->host;
@@ -180,32 +209,49 @@ static void mmc_omap_select_slot(struct mmc_omap_slot *slot, int claimed)
 	host->mmc = slot->mmc;
 	spin_unlock_irqrestore(&host->slot_lock, flags);
 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) {
+		OMAP_MMC_WRITE(host, CON, slot->saved_con & 0xFC00);
 		if (host->pdata->switch_slot != NULL)
 			host->pdata->switch_slot(mmc_dev(slot->mmc), slot->id);
 		host->current_slot = slot;
 	}
 
-	/* 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);
+	if (claimed) {
+		mmc_omap_fclk_enable(host, 1);
+
+		/* 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,
 				   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;
 	unsigned long flags;
 	int i;
 
 	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);
 	/* Check for any pending requests */
@@ -373,7 +419,7 @@ mmc_omap_xfer_done(struct mmc_omap_host *host, struct mmc_data *data)
 
 		host->mrq = NULL;
 		mmc = host->mmc;
-		mmc_omap_release_slot(host->current_slot);
+		mmc_omap_release_slot(host->current_slot, 1);
 		mmc_request_done(mmc, data->mrq);
 		return;
 	}
@@ -507,7 +553,7 @@ mmc_omap_cmd_done(struct mmc_omap_host *host, struct mmc_command *cmd)
 			mmc_omap_abort_xfer(host, host->data);
 		host->mrq = NULL;
 		mmc = host->mmc;
-		mmc_omap_release_slot(host->current_slot);
+		mmc_omap_release_slot(host->current_slot, 1);
 		mmc_request_done(mmc, cmd->mrq);
 	}
 }
@@ -538,7 +584,7 @@ static void mmc_omap_abort_command(struct work_struct *work)
 
 		host->mrq = NULL;
 		mmc = host->mmc;
-		mmc_omap_release_slot(host->current_slot);
+		mmc_omap_release_slot(host->current_slot, 1);
 		mmc_request_done(mmc, cmd->mrq);
 	} else
 		mmc_omap_cmd_done(host, host->cmd);
@@ -576,6 +622,14 @@ mmc_omap_sg_to_buf(struct mmc_omap_host *host)
 		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 */
 static void
 mmc_omap_xfer_data(struct mmc_omap_host *host, int write)
@@ -1149,14 +1203,16 @@ 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_host *host = slot->host;
 	int i, dsor;
-
-	dsor = mmc_omap_calc_divisor(mmc, ios);
+	int clk_enabled;
 
 	mmc_omap_select_slot(slot, 0);
 
+	dsor = mmc_omap_calc_divisor(mmc, ios);
+
 	if (ios->vdd != slot->vdd)
 		slot->vdd = ios->vdd;
 
+	clk_enabled = 0;
 	switch (ios->power_mode) {
 	case MMC_POWER_OFF:
 		mmc_omap_set_power(slot, 0, ios->vdd);
@@ -1166,6 +1222,8 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 		mmc_omap_set_power(slot, 1, ios->vdd);
 		goto exit;
 	case MMC_POWER_ON:
+		mmc_omap_fclk_enable(host, 1);
+		clk_enabled = 1;
 		dsor |= 1 << 11;
 		break;
 	}
@@ -1194,7 +1252,7 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 	}
 
 exit:
-	mmc_omap_release_slot(slot);
+	mmc_omap_release_slot(slot, clk_enabled);
 }
 
 static int mmc_omap_get_ro(struct mmc_host *mmc)
@@ -1357,6 +1415,9 @@ static int __init mmc_omap_probe(struct platform_device *pdev)
 	setup_timer(&host->cmd_abort_timer, mmc_omap_cmd_timer,
 		    (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);
 	setup_timer(&host->dma_timer, mmc_omap_dma_timer, (unsigned long) host);
 	spin_lock_init(&host->slot_lock);
-- 1.5.3.GIT


^ permalink raw reply related	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2008-03-26 20:17 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-01-28 19:08 [PATCH 16/18] MMC: OMAP: Lazy clock shutdown Carlos Aguiar
  -- strict thread matches above, loose matches on Subject: below --
2008-03-14 19:35 [PATCH 00/18] MMC: OMAP: Sync MMC OMAP driver with mainline tree Carlos Aguiar
2008-03-24 12:26 ` Pierre Ossman
2008-03-26 20:09   ` [PATCH 16/18] MMC: OMAP: Lazy clock shutdown Carlos Aguiar
2008-03-14 19:36 Carlos Aguiar

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