[PATCH v3] scsi: ufs: ufs-pci: Correct check for RESET DSM

[Daniil Lunev <dlunev@chromium.org>]

dsm_fns is a bitmap, and it is 0-indexed according to the check in
__intel_dsm function. But common initialization was checking it as if it
was 1-indexed. This patch corrects the discrepancy. This change won't
break any existing calls to the function, since before the change both
bits 0 and 1 were checked and needed to be set.

Signed-off-by: Daniil Lunev <dlunev@chromium.org>

---

Changes in v3:
* Commit message typos
* Args indentation

Changes in v2:
* Make __INTEL_DSM_SUPPORTED a function
* use `1u` instead of `1` in shift operator

 drivers/ufs/host/ufshcd-pci.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/ufs/host/ufshcd-pci.c b/drivers/ufs/host/ufshcd-pci.c
index 04166bda41daa..b9572fcc3bda5 100644
--- a/drivers/ufs/host/ufshcd-pci.c
+++ b/drivers/ufs/host/ufshcd-pci.c
@@ -24,7 +24,7 @@ struct ufs_host {
 	void (*late_init)(struct ufs_hba *hba);
 };
 
-enum {
+enum intel_ufs_dsm_func_id {
 	INTEL_DSM_FNS		=  0,
 	INTEL_DSM_RESET		=  1,
 };
@@ -42,6 +42,15 @@ static const guid_t intel_dsm_guid =
 	GUID_INIT(0x1A4832A0, 0x7D03, 0x43CA,
 		  0xB0, 0x20, 0xF6, 0xDC, 0xD1, 0x2A, 0x19, 0x50);
 
+static bool __intel_dsm_supported(struct intel_host *host,
+				  enum intel_ufs_dsm_func_id fn)
+{
+	return fn < 32 && fn >= 0 && (host->dsm_fns & (1u << fn));
+}
+
+#define INTEL_DSM_SUPPORTED(host, name) \
+	__intel_dsm_supported(host, INTEL_DSM_##name)
+
 static int __intel_dsm(struct intel_host *intel_host, struct device *dev,
 		       unsigned int fn, u32 *result)
 {
@@ -71,7 +80,7 @@ static int __intel_dsm(struct intel_host *intel_host, struct device *dev,
 static int intel_dsm(struct intel_host *intel_host, struct device *dev,
 		     unsigned int fn, u32 *result)
 {
-	if (fn > 31 || !(intel_host->dsm_fns & (1 << fn)))
+	if (!__intel_dsm_supported(intel_host, fn))
 		return -EOPNOTSUPP;
 
 	return __intel_dsm(intel_host, dev, fn, result);
@@ -300,7 +309,7 @@ static int ufs_intel_device_reset(struct ufs_hba *hba)
 {
 	struct intel_host *host = ufshcd_get_variant(hba);
 
-	if (host->dsm_fns & INTEL_DSM_RESET) {
+	if (INTEL_DSM_SUPPORTED(host, RESET)) {
 		u32 result = 0;
 		int err;
 
@@ -342,7 +351,7 @@ static int ufs_intel_common_init(struct ufs_hba *hba)
 		return -ENOMEM;
 	ufshcd_set_variant(hba, host);
 	intel_dsm_init(host, hba->dev);
-	if (host->dsm_fns & INTEL_DSM_RESET) {
+	if (INTEL_DSM_SUPPORTED(host, RESET)) {
 		if (hba->vops->device_reset)
 			hba->caps |= UFSHCD_CAP_DEEPSLEEP;
 	} else {
-- 
2.31.0