[PATCH v6 1/2] PCI/ASPM: Rename encode_l12_threshold(), convert arg to ns

[Bjorn Helgaas <helgaas@xxxxxxxxxx>]

From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

Rename encode_l12_threshold() to pci_lat_encode() and convert its argument
from microseconds to nanoseconds so we can share it between
LTR_L1.2_THRESHOLD encoding and LTR Max Snoop/No-Snoop Latency encoding.

Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
 drivers/pci/pcie/aspm.c | 39 ++++++++++++---------------------------
 1 file changed, 12 insertions(+), 27 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 253c30cc1967..beb6e2e4e5d2 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -307,6 +307,17 @@ static void pcie_aspm_configure_common_clock(struct pcie_link_state *link)
 	pcie_capability_write_word(parent, PCI_EXP_LNKCTL, parent_reg);
 }
 
+static void pci_lat_encode(u64 lat, u32 *scale, u32 *val)
+{
+	/* See PCIe r5.0, sec 7.8.3.3 and sec 6.18 */
+	     if (lat < 32)	 { *scale = 0; *val = (lat >>  0) & 0x3ff; }
+	else if (lat < 1024)	 { *scale = 1; *val = (lat >>  5) & 0x3ff; }
+	else if (lat < 32768)	 { *scale = 2; *val = (lat >> 10) & 0x3ff; }
+	else if (lat < 1048576)	 { *scale = 3; *val = (lat >> 15) & 0x3ff; }
+	else if (lat < 33554432) { *scale = 4; *val = (lat >> 20) & 0x3ff; }
+	else			 { *scale = 5; *val = (lat >> 25) & 0x3ff; }
+}
+
 /* Convert L0s latency encoding to ns */
 static u32 calc_l0s_latency(u32 encoding)
 {
@@ -354,32 +365,6 @@ static u32 calc_l1ss_pwron(struct pci_dev *pdev, u32 scale, u32 val)
 	return 0;
 }
 
-static void encode_l12_threshold(u32 threshold_us, u32 *scale, u32 *value)
-{
-	u32 threshold_ns = threshold_us * 1000;
-
-	/* See PCIe r3.1, sec 7.33.3 and sec 6.18 */
-	if (threshold_ns < 32) {
-		*scale = 0;
-		*value = threshold_ns;
-	} else if (threshold_ns < 1024) {
-		*scale = 1;
-		*value = threshold_ns >> 5;
-	} else if (threshold_ns < 32768) {
-		*scale = 2;
-		*value = threshold_ns >> 10;
-	} else if (threshold_ns < 1048576) {
-		*scale = 3;
-		*value = threshold_ns >> 15;
-	} else if (threshold_ns < 33554432) {
-		*scale = 4;
-		*value = threshold_ns >> 20;
-	} else {
-		*scale = 5;
-		*value = threshold_ns >> 25;
-	}
-}
-
 struct aspm_register_info {
 	u32 support:2;
 	u32 enabled:2;
@@ -539,7 +524,7 @@ static void aspm_calc_l1ss_info(struct pcie_link_state *link,
 	 * least 4us.
 	 */
 	l1_2_threshold = 2 + 4 + t_common_mode + t_power_on;
-	encode_l12_threshold(l1_2_threshold, &scale, &value);
+	pci_lat_encode(l1_2_threshold * 1000, &scale, &value);
 	link->l1ss.ctl1 |= t_common_mode << 8 | scale << 29 | value << 16;
 }
 
-- 
2.25.1