[PATCH] dma: tegra: implement suspend/resume callbacks

Laxman Dewangan
2013-04-24T09:59:11Z

Implement suspend/resume callbacks to store APB DMA channel's
register on suspend and restore APB DMA channel's register on
resume.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
---
drivers/dma/tegra20-apb-dma.c | 65 +++++++++++++++++++++++++++++++++++++++++
1 files changed, 65 insertions(+), 0 deletions(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 5a0b66c..ce19340 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -30,6 +30,7 @@
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
+#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
#include <linux/clk/tegra.h>
@@ -199,6 +200,7 @@ struct tegra_dma_channel {

/* Channel-slave specific configuration */
struct dma_slave_config dma_sconfig;
+ struct tegra_dma_channel_regs channel_reg;
};

/* tegra_dma: Tegra DMA specific information */
@@ -1440,11 +1442,74 @@ static int tegra_dma_runtime_resume(struct device *dev)
return 0;
}

+#ifdef CONFIG_PM_SLEEP
+static int tegra_dma_pm_suspend(struct device *dev)
+{
+ struct tegra_dma *tdma = dev_get_drvdata(dev);
+ int i;
+ int ret;
+
+ /* Enable clock before accessing register */
+ ret = tegra_dma_runtime_resume(dev);
+ if (ret < 0)
+ return ret;
+
+ tdma->reg_gen = tdma_read(tdma, TEGRA_APBDMA_GENERAL);
+ for (i = 0; i < tdma->chip_data->nr_channels; i++) {
+ struct tegra_dma_channel *tdc = &tdma->channels[i];
+ struct tegra_dma_channel_regs *ch_reg = &tdc->channel_reg;
+
+ ch_reg->csr = tdc_read(tdc, TEGRA_APBDMA_CHAN_CSR);
+ ch_reg->ahb_ptr = tdc_read(tdc, TEGRA_APBDMA_CHAN_AHBPTR);
+ ch_reg->apb_ptr = tdc_read(tdc, TEGRA_APBDMA_CHAN_APBPTR);
+ ch_reg->ahb_seq = tdc_read(tdc, TEGRA_APBDMA_CHAN_AHBSEQ);
+ ch_reg->apb_seq = tdc_read(tdc, TEGRA_APBDMA_CHAN_APBSEQ);
+ }
+
+ /* Disable clock */
+ tegra_dma_runtime_suspend(dev);
+ return 0;
+}
+
+static int tegra_dma_pm_resume(struct device *dev)
+{
+ struct tegra_dma *tdma = dev_get_drvdata(dev);
+ int i;
+ int ret;
+
+ /* Enable clock before accessing register */
+ ret = tegra_dma_runtime_resume(dev);
+ if (ret < 0)
+ return ret;
+
+ tdma_write(tdma, TEGRA_APBDMA_GENERAL, tdma->reg_gen);
+ tdma_write(tdma, TEGRA_APBDMA_CONTROL, 0);
+ tdma_write(tdma, TEGRA_APBDMA_IRQ_MASK_SET, 0xFFFFFFFFul);
+
+ for (i = 0; i < tdma->chip_data->nr_channels; i++) {
+ struct tegra_dma_channel *tdc = &tdma->channels[i];
+ struct tegra_dma_channel_regs *ch_reg = &tdc->channel_reg;
+
+ tdc_write(tdc, TEGRA_APBDMA_CHAN_APBSEQ, ch_reg->apb_seq);
+ tdc_write(tdc, TEGRA_APBDMA_CHAN_APBPTR, ch_reg->apb_ptr);
+ tdc_write(tdc, TEGRA_APBDMA_CHAN_AHBSEQ, ch_reg->ahb_seq);
+ tdc_write(tdc, TEGRA_APBDMA_CHAN_AHBPTR, ch_reg->ahb_ptr);
+ tdc_write(tdc, TEGRA_APBDMA_CHAN_CSR,
+ (ch_reg->csr & ~TEGRA_APBDMA_CSR_ENB));
+ }
+
+ /* Disable clock */
+ tegra_dma_runtime_suspend(dev);
+ return 0;
+}
+#endif
+
static const struct dev_pm_ops tegra_dma_dev_pm_ops = {
#ifdef CONFIG_PM_RUNTIME
.runtime_suspend = tegra_dma_runtime_suspend,
.runtime_resume = tegra_dma_runtime_resume,
#endif
+ SET_SYSTEM_SLEEP_PM_OPS(tegra_dma_pm_suspend, tegra_dma_pm_resume)
};

static struct platform_driver tegra_dmac_driver = {
--
1.7.1.1