i3c: mipi-i3c-hci: Read HC_CONTROL_PIO_MODE only after i3c hci v1.1

The HC_CONTROL_PIO_MODE bit was introduced in the HC_CONTROL register
starting from version 1.1. Therefore, checking the HC_CONTROL_PIO_MODE bit
on hardware that adheres to older specification revisions (i.e., versions
earlier than 1.1) is incorrect. To address this, add an additional check
to read the HCI version before attempting to read the HC_CONTROL_PIO_MODE
status.

Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Reviewed-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Link: https://lore.kernel.org/r/20240829091713.736217-3-Shyam-sundar.S-k@amd.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
index 07de1cecfa30c7c9caefafdafda8aa983aac2b1e..a6781cfeebb8468bad0928e5460f3ff30f8194d3 100644 (file)
--- a/drivers/i3c/master/mipi-i3c-hci/core.c
+++ b/drivers/i3c/master/mipi-i3c-hci/core.c
@@ -630,8 +630,8 @@ static irqreturn_t i3c_hci_irq_handler(int irq, void *dev_id)
 
 static int i3c_hci_init(struct i3c_hci *hci)
 {
+       bool size_in_dwords, mode_selector;
        u32 regval, offset;
-       bool size_in_dwords;
        int ret;
 
        /* Validate HCI hardware version */
@@ -753,10 +753,13 @@ static int i3c_hci_init(struct i3c_hci *hci)
                return -EINVAL;
        }
 
+       mode_selector = hci->version_major > 1 ||
+                               (hci->version_major == 1 && hci->version_minor > 0);
+
        /* Try activating DMA operations first */
        if (hci->RHS_regs) {
                reg_clear(HC_CONTROL, HC_CONTROL_PIO_MODE);
-               if (reg_read(HC_CONTROL) & HC_CONTROL_PIO_MODE) {
+               if (mode_selector && (reg_read(HC_CONTROL) & HC_CONTROL_PIO_MODE)) {
                        dev_err(&hci->master.dev, "PIO mode is stuck\n");
                        ret = -EIO;
                } else {
@@ -768,7 +771,7 @@ static int i3c_hci_init(struct i3c_hci *hci)
        /* If no DMA, try PIO */
        if (!hci->io && hci->PIO_regs) {
                reg_set(HC_CONTROL, HC_CONTROL_PIO_MODE);
-               if (!(reg_read(HC_CONTROL) & HC_CONTROL_PIO_MODE)) {
+               if (mode_selector && !(reg_read(HC_CONTROL) & HC_CONTROL_PIO_MODE)) {
                        dev_err(&hci->master.dev, "DMA mode is stuck\n");
                        ret = -EIO;
                } else {