i3c: mipi-i3c-hci: Add a quirk to set Response buffer threshold

The current driver sets the response buffer threshold value to 1
(N+1, 2 DWORDS) in the QUEUE THRESHOLD register. However, the AMD
I3C controller only generates interrupts when the response buffer
threshold value is set to 0 (1 DWORD).

Therefore, a quirk is added to set the response buffer threshold value
to 0.

Reviewed-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Co-developed-by: Krishnamoorthi M <krishnamoorthi.m@amd.com>
Signed-off-by: Krishnamoorthi M <krishnamoorthi.m@amd.com>
Co-developed-by: Guruvendra Punugupati <Guruvendra.Punugupati@amd.com>
Signed-off-by: Guruvendra Punugupati <Guruvendra.Punugupati@amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Link: https://lore.kernel.org/r/20240829091713.736217-7-Shyam-sundar.S-k@amd.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

3 files changed, 18 insertions, 1 deletions

diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
index f9ce0ee2cfd5..a82c47c9986d 100644
--- a/drivers/i3c/master/mipi-i3c-hci/core.c
+++ b/drivers/i3c/master/mipi-i3c-hci/core.c
@@ -146,6 +146,10 @@ static int i3c_hci_bus_init(struct i3c_master_controller *m)
 	if (ret)
 		return ret;
 
+	/* Set RESP_BUF_THLD to 0(n) to get 1(n+1) response */
+	if (hci->quirks & HCI_QUIRK_RESP_BUF_THLD)
+		amd_set_resp_buf_thld(hci);
+
 	reg_set(HC_CONTROL, HC_CONTROL_BUS_ENABLE);
 	DBG("HC_CONTROL = %#x", reg_read(HC_CONTROL));
 
@@ -842,7 +846,7 @@ static const __maybe_unused struct of_device_id i3c_hci_of_match[] = {
 MODULE_DEVICE_TABLE(of, i3c_hci_of_match);
 
 static const struct acpi_device_id i3c_hci_acpi_match[] = {
-	{ "AMDI5017", HCI_QUIRK_PIO_MODE | HCI_QUIRK_OD_PP_TIMING },
+	{ "AMDI5017", HCI_QUIRK_PIO_MODE | HCI_QUIRK_OD_PP_TIMING | HCI_QUIRK_RESP_BUF_THLD },
 	{}
 };
 MODULE_DEVICE_TABLE(acpi, i3c_hci_acpi_match);
diff --git a/drivers/i3c/master/mipi-i3c-hci/hci.h b/drivers/i3c/master/mipi-i3c-hci/hci.h
index 361e1366fe38..aaa47ac47381 100644
--- a/drivers/i3c/master/mipi-i3c-hci/hci.h
+++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
@@ -142,6 +142,7 @@ struct i3c_hci_dev_data {
 #define HCI_QUIRK_RAW_CCC	BIT(1)	/* CCC framing must be explicit */
 #define HCI_QUIRK_PIO_MODE	BIT(2)  /* Set PIO mode for AMD platforms */
 #define HCI_QUIRK_OD_PP_TIMING		BIT(3)  /* Set OD and PP timings for AMD platforms */
+#define HCI_QUIRK_RESP_BUF_THLD		BIT(4)  /* Set resp buf thld to 0 for AMD platforms */
 
 
 /* global functions */
@@ -149,5 +150,6 @@ void mipi_i3c_hci_resume(struct i3c_hci *hci);
 void mipi_i3c_hci_pio_reset(struct i3c_hci *hci);
 void mipi_i3c_hci_dct_index_reset(struct i3c_hci *hci);
 void amd_set_od_pp_timing(struct i3c_hci *hci);
+void amd_set_resp_buf_thld(struct i3c_hci *hci);
 
 #endif
diff --git a/drivers/i3c/master/mipi-i3c-hci/hci_quirks.c b/drivers/i3c/master/mipi-i3c-hci/hci_quirks.c
index e8ea4d101f66..3b9c6e76c536 100644
--- a/drivers/i3c/master/mipi-i3c-hci/hci_quirks.c
+++ b/drivers/i3c/master/mipi-i3c-hci/hci_quirks.c
@@ -20,6 +20,8 @@
 #define AMD_SCL_I3C_OD_TIMING          0x00cf00cf
 #define AMD_SCL_I3C_PP_TIMING          0x00160016
 
+#define QUEUE_THLD_CTRL                0xD0
+
 void amd_set_od_pp_timing(struct i3c_hci *hci)
 {
 	u32 data;
@@ -31,3 +33,12 @@ void amd_set_od_pp_timing(struct i3c_hci *hci)
 	data |= W0_MASK(18, 16);
 	reg_write(HCI_SDA_HOLD_SWITCH_DLY_TIMING, data);
 }
+
+void amd_set_resp_buf_thld(struct i3c_hci *hci)
+{
+	u32 data;
+
+	data = reg_read(QUEUE_THLD_CTRL);
+	data = data & ~W0_MASK(15, 8);
+	reg_write(QUEUE_THLD_CTRL, data);
+}