Commit ae43b328 authored by Krzysztof Kozlowski's avatar Krzysztof Kozlowski Committed by Russell King

ARM: 8202/1: dmaengine: pl330: Add runtime Power Management support v12

This patch adds runtime PM support to pl330 DMA engine driver.

The runtime power management for pl330 DMA driver allows gating of AMBA
clock (PDMA) in FSYS clock domain, when the device is not processing any
requests. This is necessary to enter low power modes on Exynos SoCs
(e.g. LPA on Exynos4x12 or W-AFTR on Exynos3250).

Runtime PM resuming of the device may happen in atomic context (during
call device_issue_pending()) so pm_runtime_irq_safe() is used. This will
lead only to disabling/enabling of the clock but this is sufficient for
gating the clock and for reducing energy usage.

Driver uses runtime PM callbacks from amba/bus.c driver only.
Suggested-by: default avatarBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: default avatarKrzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Acked-by: default avatarVinod Koul <vinod.koul@intel.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 5670c2a5
...@@ -27,6 +27,7 @@ ...@@ -27,6 +27,7 @@
#include <linux/of.h> #include <linux/of.h>
#include <linux/of_dma.h> #include <linux/of_dma.h>
#include <linux/err.h> #include <linux/err.h>
#include <linux/pm_runtime.h>
#include "dmaengine.h" #include "dmaengine.h"
#define PL330_MAX_CHAN 8 #define PL330_MAX_CHAN 8
...@@ -265,6 +266,9 @@ static unsigned cmd_line; ...@@ -265,6 +266,9 @@ static unsigned cmd_line;
#define NR_DEFAULT_DESC 16 #define NR_DEFAULT_DESC 16
/* Delay for runtime PM autosuspend, ms */
#define PL330_AUTOSUSPEND_DELAY 20
/* Populated by the PL330 core driver for DMA API driver's info */ /* Populated by the PL330 core driver for DMA API driver's info */
struct pl330_config { struct pl330_config {
u32 periph_id; u32 periph_id;
...@@ -1958,6 +1962,7 @@ static void pl330_tasklet(unsigned long data) ...@@ -1958,6 +1962,7 @@ static void pl330_tasklet(unsigned long data)
struct dma_pl330_chan *pch = (struct dma_pl330_chan *)data; struct dma_pl330_chan *pch = (struct dma_pl330_chan *)data;
struct dma_pl330_desc *desc, *_dt; struct dma_pl330_desc *desc, *_dt;
unsigned long flags; unsigned long flags;
bool power_down = false;
spin_lock_irqsave(&pch->lock, flags); spin_lock_irqsave(&pch->lock, flags);
...@@ -1972,10 +1977,17 @@ static void pl330_tasklet(unsigned long data) ...@@ -1972,10 +1977,17 @@ static void pl330_tasklet(unsigned long data)
/* Try to submit a req imm. next to the last completed cookie */ /* Try to submit a req imm. next to the last completed cookie */
fill_queue(pch); fill_queue(pch);
if (list_empty(&pch->work_list)) {
spin_lock(&pch->thread->dmac->lock);
_stop(pch->thread);
spin_unlock(&pch->thread->dmac->lock);
power_down = true;
} else {
/* Make sure the PL330 Channel thread is active */ /* Make sure the PL330 Channel thread is active */
spin_lock(&pch->thread->dmac->lock); spin_lock(&pch->thread->dmac->lock);
_start(pch->thread); _start(pch->thread);
spin_unlock(&pch->thread->dmac->lock); spin_unlock(&pch->thread->dmac->lock);
}
while (!list_empty(&pch->completed_list)) { while (!list_empty(&pch->completed_list)) {
dma_async_tx_callback callback; dma_async_tx_callback callback;
...@@ -1990,6 +2002,12 @@ static void pl330_tasklet(unsigned long data) ...@@ -1990,6 +2002,12 @@ static void pl330_tasklet(unsigned long data)
if (pch->cyclic) { if (pch->cyclic) {
desc->status = PREP; desc->status = PREP;
list_move_tail(&desc->node, &pch->work_list); list_move_tail(&desc->node, &pch->work_list);
if (power_down) {
spin_lock(&pch->thread->dmac->lock);
_start(pch->thread);
spin_unlock(&pch->thread->dmac->lock);
power_down = false;
}
} else { } else {
desc->status = FREE; desc->status = FREE;
list_move_tail(&desc->node, &pch->dmac->desc_pool); list_move_tail(&desc->node, &pch->dmac->desc_pool);
...@@ -2004,6 +2022,12 @@ static void pl330_tasklet(unsigned long data) ...@@ -2004,6 +2022,12 @@ static void pl330_tasklet(unsigned long data)
} }
} }
spin_unlock_irqrestore(&pch->lock, flags); spin_unlock_irqrestore(&pch->lock, flags);
/* If work list empty, power down */
if (power_down) {
pm_runtime_mark_last_busy(pch->dmac->ddma.dev);
pm_runtime_put_autosuspend(pch->dmac->ddma.dev);
}
} }
bool pl330_filter(struct dma_chan *chan, void *param) bool pl330_filter(struct dma_chan *chan, void *param)
...@@ -2073,6 +2097,7 @@ static int pl330_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned ...@@ -2073,6 +2097,7 @@ static int pl330_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned
switch (cmd) { switch (cmd) {
case DMA_TERMINATE_ALL: case DMA_TERMINATE_ALL:
pm_runtime_get_sync(pl330->ddma.dev);
spin_lock_irqsave(&pch->lock, flags); spin_lock_irqsave(&pch->lock, flags);
spin_lock(&pl330->lock); spin_lock(&pl330->lock);
...@@ -2099,10 +2124,15 @@ static int pl330_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned ...@@ -2099,10 +2124,15 @@ static int pl330_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned
dma_cookie_complete(&desc->txd); dma_cookie_complete(&desc->txd);
} }
if (!list_empty(&pch->work_list))
pm_runtime_put(pl330->ddma.dev);
list_splice_tail_init(&pch->submitted_list, &pl330->desc_pool); list_splice_tail_init(&pch->submitted_list, &pl330->desc_pool);
list_splice_tail_init(&pch->work_list, &pl330->desc_pool); list_splice_tail_init(&pch->work_list, &pl330->desc_pool);
list_splice_tail_init(&pch->completed_list, &pl330->desc_pool); list_splice_tail_init(&pch->completed_list, &pl330->desc_pool);
spin_unlock_irqrestore(&pch->lock, flags); spin_unlock_irqrestore(&pch->lock, flags);
pm_runtime_mark_last_busy(pl330->ddma.dev);
pm_runtime_put_autosuspend(pl330->ddma.dev);
break; break;
case DMA_SLAVE_CONFIG: case DMA_SLAVE_CONFIG:
slave_config = (struct dma_slave_config *)arg; slave_config = (struct dma_slave_config *)arg;
...@@ -2138,6 +2168,7 @@ static void pl330_free_chan_resources(struct dma_chan *chan) ...@@ -2138,6 +2168,7 @@ static void pl330_free_chan_resources(struct dma_chan *chan)
tasklet_kill(&pch->task); tasklet_kill(&pch->task);
pm_runtime_get_sync(pch->dmac->ddma.dev);
spin_lock_irqsave(&pch->lock, flags); spin_lock_irqsave(&pch->lock, flags);
pl330_release_channel(pch->thread); pl330_release_channel(pch->thread);
...@@ -2147,6 +2178,8 @@ static void pl330_free_chan_resources(struct dma_chan *chan) ...@@ -2147,6 +2178,8 @@ static void pl330_free_chan_resources(struct dma_chan *chan)
list_splice_tail_init(&pch->work_list, &pch->dmac->desc_pool); list_splice_tail_init(&pch->work_list, &pch->dmac->desc_pool);
spin_unlock_irqrestore(&pch->lock, flags); spin_unlock_irqrestore(&pch->lock, flags);
pm_runtime_mark_last_busy(pch->dmac->ddma.dev);
pm_runtime_put_autosuspend(pch->dmac->ddma.dev);
} }
static enum dma_status static enum dma_status
...@@ -2162,6 +2195,15 @@ static void pl330_issue_pending(struct dma_chan *chan) ...@@ -2162,6 +2195,15 @@ static void pl330_issue_pending(struct dma_chan *chan)
unsigned long flags; unsigned long flags;
spin_lock_irqsave(&pch->lock, flags); spin_lock_irqsave(&pch->lock, flags);
if (list_empty(&pch->work_list)) {
/*
* Warn on nothing pending. Empty submitted_list may
* break our pm_runtime usage counter as it is
* updated on work_list emptiness status.
*/
WARN_ON(list_empty(&pch->submitted_list));
pm_runtime_get_sync(pch->dmac->ddma.dev);
}
list_splice_tail_init(&pch->submitted_list, &pch->work_list); list_splice_tail_init(&pch->submitted_list, &pch->work_list);
spin_unlock_irqrestore(&pch->lock, flags); spin_unlock_irqrestore(&pch->lock, flags);
...@@ -2738,6 +2780,12 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id) ...@@ -2738,6 +2780,12 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
pcfg->data_buf_dep, pcfg->data_bus_width / 8, pcfg->num_chan, pcfg->data_buf_dep, pcfg->data_bus_width / 8, pcfg->num_chan,
pcfg->num_peri, pcfg->num_events); pcfg->num_peri, pcfg->num_events);
pm_runtime_irq_safe(&adev->dev);
pm_runtime_use_autosuspend(&adev->dev);
pm_runtime_set_autosuspend_delay(&adev->dev, PL330_AUTOSUSPEND_DELAY);
pm_runtime_mark_last_busy(&adev->dev);
pm_runtime_put_autosuspend(&adev->dev);
return 0; return 0;
probe_err3: probe_err3:
/* Idle the DMAC */ /* Idle the DMAC */
...@@ -2764,6 +2812,8 @@ static int pl330_remove(struct amba_device *adev) ...@@ -2764,6 +2812,8 @@ static int pl330_remove(struct amba_device *adev)
struct pl330_dmac *pl330 = amba_get_drvdata(adev); struct pl330_dmac *pl330 = amba_get_drvdata(adev);
struct dma_pl330_chan *pch, *_p; struct dma_pl330_chan *pch, *_p;
pm_runtime_get_noresume(pl330->ddma.dev);
if (adev->dev.of_node) if (adev->dev.of_node)
of_dma_controller_free(adev->dev.of_node); of_dma_controller_free(adev->dev.of_node);
......
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