[PATCH 08/17] i3c: mipi-i3c-hci: Cache DAT in memory for Runtime PM restore

Adrian Hunter
2025-12-19T14:46:09Z

Prepare for Runtime PM support, which requires restoring the Device Address
Table (DAT) registers after resume. Maintain a copy of DAT in memory so it
can be reprogrammed when the controller is powered back up.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
drivers/i3c/master/mipi-i3c-hci/dat_v1.c | 29 +++++++++++++++++++-----
drivers/i3c/master/mipi-i3c-hci/hci.h | 6 +++++
2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
index c60ef5d77ca3..644ab939be1c 100644
--- a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
+++ b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
@@ -34,13 +34,26 @@
/* DAT_0_IBI_PAYLOAD W0_BIT_(12) */
#define DAT_0_STATIC_ADDRESS W0_MASK(6, 0)

-#define dat_w0_read(i) readl(hci->DAT_regs + (i) * 8)
-#define dat_w1_read(i) readl(hci->DAT_regs + (i) * 8 + 4)
-#define dat_w0_write(i, v) writel(v, hci->DAT_regs + (i) * 8)
-#define dat_w1_write(i, v) writel(v, hci->DAT_regs + (i) * 8 + 4)
+#define dat_w0_read(i) hci->DAT[i].w0
+#define dat_w1_read(i) hci->DAT[i].w1
+#define dat_w0_write(i, v) hci_dat_w0_write(hci, i, v)
+#define dat_w1_write(i, v) hci_dat_w1_write(hci, i, v)
+
+static inline void hci_dat_w0_write(struct i3c_hci *hci, int i, u32 v)
+{
+ hci->DAT[i].w0 = v;
+ writel(v, hci->DAT_regs + i * 8);
+}
+
+static inline void hci_dat_w1_write(struct i3c_hci *hci, int i, u32 v)
+{
+ hci->DAT[i].w1 = v;
+ writel(v, hci->DAT_regs + i * 8 + 4);
+}

static int hci_dat_v1_init(struct i3c_hci *hci)
{
+ struct device *dev = hci->master.dev.parent;
unsigned int dat_idx;

if (!hci->DAT_regs) {
@@ -54,9 +67,13 @@ static int hci_dat_v1_init(struct i3c_hci *hci)
return -EOPNOTSUPP;
}

- if (!hci->DAT_data) {
- struct device *dev = hci->master.dev.parent;
+ if (!hci->DAT) {
+ hci->DAT = devm_kcalloc(dev, hci->DAT_entries, hci->DAT_entry_size, GFP_KERNEL);
+ if (!hci->DAT)
+ return -ENOMEM;
+ }

+ if (!hci->DAT_data) {
/* use a bitmap for faster free slot search */
hci->DAT_data = devm_bitmap_zalloc(dev, hci->DAT_entries, GFP_KERNEL);
if (!hci->DAT_data)
diff --git a/drivers/i3c/master/mipi-i3c-hci/hci.h b/drivers/i3c/master/mipi-i3c-hci/hci.h
index fd08b701d094..aa8a03594e64 100644
--- a/drivers/i3c/master/mipi-i3c-hci/hci.h
+++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
@@ -31,6 +31,11 @@

struct hci_cmd_ops;

+struct dat_words {
+ u32 w0;
+ u32 w1;
+};
+
/* Our main structure */
struct i3c_hci {
struct i3c_master_controller master;
@@ -51,6 +56,7 @@ struct i3c_hci {
unsigned int DAT_entries;
unsigned int DAT_entry_size;
void *DAT_data;
+ struct dat_words *DAT;
unsigned int DCT_entries;
unsigned int DCT_entry_size;
u8 version_major;
--
2.51.0