[PATCH v2 5/5] i3c: mipi-i3c-hci: Add a quirk to set Response buffer threshold

Shyam Sundar S K
2024-07-24T07:13:44Z

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.

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>
---
drivers/i3c/master/mipi-i3c-hci/core.c | 4 ++++
drivers/i3c/master/mipi-i3c-hci/hci.h | 2 ++
drivers/i3c/master/mipi-i3c-hci/hci_quirks.c | 12 ++++++++++++
3 files changed, 18 insertions(+)

diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
index 3320e6331c86..eef5059177f1 100644
--- a/drivers/i3c/master/mipi-i3c-hci/core.c
+++ b/drivers/i3c/master/mipi-i3c-hci/core.c
@@ -147,6 +147,10 @@ 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_AMD_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));

diff --git a/drivers/i3c/master/mipi-i3c-hci/hci.h b/drivers/i3c/master/mipi-i3c-hci/hci.h
index 06a4d54a5a02..58c3643c6390 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_AMD_PIO_MODE BIT(2) /* Set PIO mode for AMD platforms */
#define HCI_QUIRK_AMD_OD_PP_TIMING BIT(3) /* Set OD and PP timings for AMD platforms */
+#define HCI_QUIRK_AMD_RESP_BUF_THLD BIT(4) /* Set resp buf thld to 0 for AMD platforms */

/* global functions */
@@ -151,5 +152,6 @@ void mipi_i3c_hci_dct_index_reset(struct i3c_hci *hci);

void amd_i3c_hci_quirks_init(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 6ce08f9c92a8..954cba95e4a4 100644
--- a/drivers/i3c/master/mipi-i3c-hci/hci_quirks.c
+++ b/drivers/i3c/master/mipi-i3c-hci/hci_quirks.c
@@ -20,12 +20,15 @@
#define AMD_SCL_I3C_OD_TIMING 0x00cf00cf
#define AMD_SCL_I3C_PP_TIMING 0x00160016

+#define QUEUE_THLD_CTRL 0xD0
+
void amd_i3c_hci_quirks_init(struct i3c_hci *hci)
{
#if defined(CONFIG_X86)
if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
hci->quirks |= HCI_QUIRK_AMD_PIO_MODE;
hci->quirks |= HCI_QUIRK_AMD_OD_PP_TIMING;
+ hci->quirks |= HCI_QUIRK_AMD_RESP_BUF_THLD;
}
#endif
}
@@ -41,3 +44,12 @@ 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);
+}