This patch makes the edma driver resume correctly after suspend. Tested
on an AM33xx platform with cyclic audio streams.

The code was shamelessly taken from an ancient BSP tree.

Signed-off-by: Daniel Mack <zon...@gmail.com>
---
 arch/arm/common/edma.c | 133 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 133 insertions(+)

diff --git a/arch/arm/common/edma.c b/arch/arm/common/edma.c
index 2a72169..d787f14 100644
--- a/arch/arm/common/edma.c
+++ b/arch/arm/common/edma.c
@@ -258,6 +258,20 @@ struct edma {
                                void *data);
                void *data;
        } intr_data[EDMA_MAX_DMACH];
+
+       struct {
+               struct edmacc_param *prm_set;
+               unsigned int *ch_map;               /* 64 registers */
+               unsigned int *que_num;              /* 8 registers */
+               unsigned int sh_esr;
+               unsigned int sh_esrh;
+               unsigned int sh_eesr;
+               unsigned int sh_eesrh;
+               unsigned int sh_iesr;
+               unsigned int sh_iesrh;
+               unsigned int que_tc_map;
+               unsigned int que_pri;
+       } context;
 };
 
 static struct edma *edma_cc[EDMA_MAX_CC];
@@ -1655,6 +1669,16 @@ static int edma_probe(struct platform_device *pdev)
                        memcpy_toio(edmacc_regs_base[j] + PARM_OFFSET(i),
                                        &dummy_paramset, PARM_SIZE);
 
+               /* resume context */
+               edma_cc[j]->context.prm_set =
+                       kzalloc((sizeof(struct edmacc_param) *
+                                edma_cc[j]->num_slots), GFP_KERNEL);
+               edma_cc[j]->context.ch_map =
+                       kzalloc((sizeof(unsigned int) *
+                                edma_cc[j]->num_channels), GFP_KERNEL);
+               edma_cc[j]->context.que_num =
+                       kzalloc((sizeof(unsigned int) * 8), GFP_KERNEL);
+
                /* Mark all channels as unused */
                memset(edma_cc[j]->edma_unused, 0xff,
                        sizeof(edma_cc[j]->edma_unused));
@@ -1762,6 +1786,114 @@ static int edma_probe(struct platform_device *pdev)
        return 0;
 }
 
+static int edma_pm_suspend(struct device *dev)
+{
+       int i, j;
+
+       pm_runtime_get_sync(dev);
+
+       for (i = 0; i < arch_num_cc; i++) {
+               struct edma *ecc = edma_cc[i];
+
+               /* backup channel data */
+               for (j = 0; j < ecc->num_channels; j++)
+                       ecc->context.ch_map[j] =
+                               edma_read_array(i, EDMA_DCHMAP, j);
+
+               /* backup DMA Queue Number */
+               for (j = 0; j < 8; j++)
+                       ecc->context.que_num[j] =
+                               edma_read_array(i, EDMA_DMAQNUM, j);
+
+               /* backup DMA shadow Event Set data */
+               ecc->context.sh_esr = edma_shadow0_read_array(i, SH_ESR, 0);
+               ecc->context.sh_esrh = edma_shadow0_read_array(i, SH_ESR, 1);
+
+               /* backup DMA Shadow Event Enable Set data */
+               ecc->context.sh_eesr =
+                       edma_shadow0_read_array(i, SH_EER, 0);
+               ecc->context.sh_eesrh =
+                       edma_shadow0_read_array(i, SH_EER, 1);
+
+               /* backup DMA Shadow Interrupt Enable Set data */
+               ecc->context.sh_iesr =
+                       edma_shadow0_read_array(i, SH_IER, 0);
+               ecc->context.sh_iesrh =
+                       edma_shadow0_read_array(i, SH_IER, 1);
+
+               ecc->context.que_tc_map = edma_read(i, EDMA_QUETCMAP);
+
+               /* backup DMA Queue Priority data */
+               ecc->context.que_pri = edma_read(i, EDMA_QUEPRI);
+
+               /* backup paramset */
+               for (j = 0; j < ecc->num_slots; j++)
+                       memcpy_fromio(&ecc->context.prm_set[j],
+                                     edmacc_regs_base[i] + PARM_OFFSET(j),
+                                     PARM_SIZE);
+       }
+
+       pm_runtime_put_sync(dev);
+
+       return 0;
+}
+
+static int edma_pm_resume(struct device *dev)
+{
+       int i, j;
+
+       pm_runtime_get_sync(dev);
+
+       for (i = 0; i < arch_num_cc; i++) {
+               struct edma *ecc = edma_cc[i];
+
+               /* restore channel data */
+               for (j = 0; j < ecc->num_channels; j++) {
+                       edma_write_array(i, EDMA_DCHMAP, j,
+                                        ecc->context.ch_map[j]);
+               }
+
+               /* restore DMA Queue Number */
+               for (j = 0; j < 8; j++) {
+                       edma_write_array(i, EDMA_DMAQNUM, j,
+                                        ecc->context.que_num[j]);
+               }
+
+               /* restore DMA shadow Event Set data */
+               edma_shadow0_write_array(i, SH_ESR, 0, ecc->context.sh_esr);
+               edma_shadow0_write_array(i, SH_ESR, 1, ecc->context.sh_esrh);
+
+               /* restore DMA Shadow Event Enable Set data */
+               edma_shadow0_write_array(i, SH_EESR, 0,
+                                        ecc->context.sh_eesr);
+               edma_shadow0_write_array(i, SH_EESR, 1,
+                                        ecc->context.sh_eesrh);
+
+               /* restore DMA Shadow Interrupt Enable Set data */
+               edma_shadow0_write_array(i, SH_IESR, 0,
+                                        ecc->context.sh_iesr);
+               edma_shadow0_write_array(i, SH_IESR, 1,
+                                        ecc->context.sh_iesrh);
+
+               edma_write(i, EDMA_QUETCMAP, ecc->context.que_tc_map);
+
+               /* restore DMA Queue Priority data */
+               edma_write(i, EDMA_QUEPRI, ecc->context.que_pri);
+
+               /* restore paramset */
+               for (j = 0; j < ecc->num_slots; j++) {
+                       memcpy_toio(edmacc_regs_base[i] + PARM_OFFSET(j),
+                                   &ecc->context.prm_set[j], PARM_SIZE);
+               }
+       }
+
+       pm_runtime_put_sync(dev);
+
+       return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(edma_pm_ops, edma_pm_suspend, edma_pm_resume);
+
 static const struct of_device_id edma_of_ids[] = {
        { .compatible = "ti,edma3", },
        {}
@@ -1770,6 +1902,7 @@ static const struct of_device_id edma_of_ids[] = {
 static struct platform_driver edma_driver = {
        .driver = {
                .name   = "edma",
+               .pm     = &edma_pm_ops,
                .of_match_table = edma_of_ids,
        },
        .probe = edma_probe,
-- 
1.8.3.1

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