[PATCH V3 3/3] scsi: ufs-qcom: Add support for testbus registers

[Manish Pandey <quic_mapa@xxxxxxxxxxx>]

This patch introduces support for dumping testbus registers,
enhancing the debugging capabilities for UFS-QCOM drivers.

Signed-off-by: Manish Pandey <quic_mapa@xxxxxxxxxxx>
---
Changes in v3:
- Annotated the 'testbus' declaration with __free.
- Converted the switch-statements into an array lookup.
- Introduced struct testbus_info{} for handling testbus switch-statements to an array lookup.
Changes in v2:
- Rebased patchsets.
- Link to v1: https://lore.kernel.org/linux-arm-msm/20241025055054.23170-1-quic_mapa@xxxxxxxxxxx/

---
 drivers/ufs/host/ufs-qcom.c | 53 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 52 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index fb9da04c0d35..c32b1268d299 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -17,6 +17,7 @@
 #include <linux/time.h>
 #include <linux/unaligned.h>
 #include <linux/units.h>
+#include <linux/cleanup.h>
 
 #include <soc/qcom/ice.h>
 
@@ -98,6 +99,24 @@ static const struct __ufs_qcom_bw_table {
 	[MODE_MAX][0][0]		    = { 7643136,	819200 },
 };
 
+static const struct {
+	int nminor;
+	char *prefix;
+} testbus_info[TSTBUS_MAX] = {
+	[TSTBUS_UAWM]     = {32, "TSTBUS_UAWM "},
+	[TSTBUS_UARM]     = {32, "TSTBUS_UARM "},
+	[TSTBUS_TXUC]     = {32, "TSTBUS_TXUC "},
+	[TSTBUS_RXUC]     = {32, "TSTBUS_RXUC "},
+	[TSTBUS_DFC]      = {32, "TSTBUS_DFC "},
+	[TSTBUS_TRLUT]    = {32, "TSTBUS_TRLUT "},
+	[TSTBUS_TMRLUT]   = {32, "TSTBUS_TMRLUT "},
+	[TSTBUS_OCSC]     = {32, "TSTBUS_OCSC "},
+	[TSTBUS_UTP_HCI]  = {32, "TSTBUS_UTP_HCI "},
+	[TSTBUS_COMBINED] = {32, "TSTBUS_COMBINED "},
+	[TSTBUS_WRAPPER]  = {32, "TSTBUS_WRAPPER "},
+	[TSTBUS_UNIPRO]   = {256, "TSTBUS_UNIPRO "}
+};
+
 static void ufs_qcom_get_default_testbus_cfg(struct ufs_qcom_host *host);
 static int ufs_qcom_set_core_clk_ctrl(struct ufs_hba *hba, unsigned long freq);
 
@@ -1566,6 +1585,33 @@ int ufs_qcom_testbus_config(struct ufs_qcom_host *host)
 	return 0;
 }
 
+static void ufs_qcom_dump_testbus(struct ufs_hba *hba)
+{
+	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
+	int i, j, nminor = 0, testbus_len = 0;
+	u32 *testbus __free(kfree) = NULL;
+	char *prefix;
+
+	testbus = kmalloc(256 * sizeof(u32), GFP_KERNEL);
+	if (!testbus)
+		return;
+
+	for (j = 0; j < TSTBUS_MAX; j++) {
+		nminor = testbus_info[j].nminor;
+		prefix = testbus_info[j].prefix;
+		host->testbus.select_major = j;
+		testbus_len = nminor * sizeof(u32);
+		for (i = 0; i < nminor; i++) {
+			host->testbus.select_minor = i;
+			ufs_qcom_testbus_config(host);
+			testbus[i] = ufshcd_readl(hba, UFS_TEST_BUS);
+			usleep_range(100, 200);
+		}
+		print_hex_dump(KERN_ERR, prefix, DUMP_PREFIX_OFFSET,
+				16, 4, testbus, testbus_len, false);
+	}
+}
+
 static void ufs_qcom_dump_mcq_hci_regs(struct ufs_hba *hba)
 {
 	/* sleep intermittently to prevent CPU hog during data dumps. */
@@ -1680,9 +1726,14 @@ static void ufs_qcom_dump_dbg_regs(struct ufs_hba *hba)
 
 	/* ensure below dumps occur only in task context due to blocking calls. */
 	if (in_task()) {
-		/* Dump MCQ Host Vendor Specific Registers */
+		/* dump MCQ Host Vendor Specific Registers */
 		if (hba->mcq_enabled)
 			ufs_qcom_dump_mcq_hci_regs(hba);
+
+		/* sleep a bit intermittently as we are dumping too much data */
+		ufshcd_dump_regs(hba, UFS_TEST_BUS, 4, "UFS_TEST_BUS ");
+		usleep_range(1000, 1100);
+		ufs_qcom_dump_testbus(hba);
 	}
 }
 
-- 
2.17.1