[PATCH 12/14] dmaengine: ti: omap-dma: Use cpu notifier to block idle for omap2

Tony Lindgren
2019-12-17T00:20:06Z

For omap2, we need to block idle if SDMA is busy. Let's do this with a
cpu notifier and remove the custom call.

Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
arch/arm/mach-omap2/pm24xx.c | 22 +++++++++----------
drivers/dma/ti/omap-dma.c | 41 +++++++++++++++++++++++++++++++++++-
2 files changed, 50 insertions(+), 13 deletions(-)

diff --git a/arch/arm/mach-omap2/pm24xx.c b/arch/arm/mach-omap2/pm24xx.c
--- a/arch/arm/mach-omap2/pm24xx.c
+++ b/arch/arm/mach-omap2/pm24xx.c
@@ -83,8 +83,6 @@ static int omap2_enter_full_retention(void)
l = omap_ctrl_readl(OMAP2_CONTROL_DEVCONF0) | OMAP24XX_USBSTANDBYCTRL;
omap_ctrl_writel(l, OMAP2_CONTROL_DEVCONF0);

- cpu_cluster_pm_enter();
-
/* One last check for pending IRQs to avoid extra latency due
* to sleeping unnecessarily. */
if (omap_irq_pending())
@@ -96,8 +94,6 @@ static int omap2_enter_full_retention(void)
OMAP_SDRC_REGADDR(SDRC_POWER));

no_sleep:
- cpu_cluster_pm_exit();
-
clk_enable(osc_ck);

/* clear CORE wake-up events */
@@ -162,25 +158,27 @@ static int omap2_can_sleep(void)
return 0;
if (__clk_is_enabled(osc_ck))
return 0;
- if (omap_dma_running())
- return 0;

return 1;
}

static void omap2_pm_idle(void)
{
- if (!omap2_can_sleep()) {
- if (omap_irq_pending())
- return;
- omap2_enter_mpu_retention();
- return;
- }
+ int error;

if (omap_irq_pending())
return;

+ error = cpu_cluster_pm_enter();
+ if (error || !omap2_can_sleep()) {
+ omap2_enter_mpu_retention();
+ goto out_cpu_cluster_pm;
+ }
+
omap2_enter_full_retention();
+
+out_cpu_cluster_pm:
+ cpu_cluster_pm_exit();
}

static void __init prcm_setup_regs(void)
diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c
--- a/drivers/dma/ti/omap-dma.c
+++ b/drivers/dma/ti/omap-dma.c
@@ -27,6 +27,7 @@
struct omap_dma_config {
int lch_end;
unsigned int rw_priority:1;
+ unsigned int needs_busy_check:1;
unsigned int may_lose_context:1;
unsigned int needs_lch_clear:1;
};
@@ -1521,6 +1522,40 @@ static void omap_dma_free(struct omap_dmadev *od)
}
}

+/* Currently only used for omap2. For omap1, also a check for lcd_dma is needed */
+static int omap_dma_busy_notifier(struct notifier_block *nb,
+ unsigned long cmd, void *v)
+{
+ struct omap_dmadev *od;
+ struct omap_chan *c;
+ int lch = -1;
+
+ od = container_of(nb, struct omap_dmadev, nb);
+
+ switch (cmd) {
+ case CPU_CLUSTER_PM_ENTER:
+ while (1) {
+ lch = find_next_bit(od->lch_bitmap, od->lch_count,
+ lch + 1);
+ if (lch >= od->lch_count)
+ break;
+ c = od->lch_map[lch];
+ if (!c)
+ continue;
+ if (omap_dma_chan_read(c, CCR) & CCR_ENABLE) {
+ pr_info("XXX %s: lch%i busy\n", __func__, lch);
+ return NOTIFY_BAD;
+ }
+ }
+ break;
+ case CPU_CLUSTER_PM_ENTER_FAILED:
+ case CPU_CLUSTER_PM_EXIT:
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
/*
* We are using IRQENABLE_L1, and legacy DMA code was using IRQENABLE_L0.
* As the DSP may be using IRQENABLE_L2 and L3, let's not touch those for
@@ -1778,7 +1813,10 @@ static int omap_dma_probe(struct platform_device *pdev)

omap_dma_init_gcr(od, DMA_DEFAULT_ARB_RATE, DMA_DEFAULT_FIFO_DEPTH, 0);

- if (od->cfg->may_lose_context) {
+ if (od->cfg->needs_busy_check) {
+ od->nb.notifier_call = omap_dma_busy_notifier;
+ cpu_pm_register_notifier(&od->nb);
+ } else if (od->cfg->may_lose_context) {
od->nb.notifier_call = omap_dma_context_notifier;
cpu_pm_register_notifier(&od->nb);
}
@@ -1822,6 +1860,7 @@ static const struct omap_dma_config omap2420_data = {
.lch_end = CCFN,
.rw_priority = true,
.needs_lch_clear = true,
+ .needs_busy_check = true,
};

static const struct omap_dma_config omap2430_data = {
--
2.24.1