[PATCH edk2-platforms 1/8] Silicon/SynQuacer/PlatformDxe: enable spread spectrum mode for ASM1061 SATA

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

The ASM1061 SATA controller integrated into the DeveloperBox board
emits too much electromagnetic radiation, so it needs spread spectrum
mode enabled.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
---
 Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/{Asmedia118x.c => Pci.c} | 83 +++++++++++++++-----
 Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.inf          |  2 +-
 2 files changed, 64 insertions(+), 21 deletions(-)

diff --git a/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/Asmedia118x.c b/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/Pci.c
similarity index 64%
rename from Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/Asmedia118x.c
rename to Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/Pci.c
index 874e83a649b5..9af3dd942cdd 100644
--- a/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/Asmedia118x.c
+++ b/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/Pci.c
@@ -15,9 +15,12 @@
 #include "PlatformDxe.h"
 
 #define ASMEDIA_VID                         0x1b21
+#define ASM1061_PID                         0x0612
 #define ASM1182E_PID                        0x1182
 #define ASM1184E_PID                        0x1184
 
+#define ASM1061_SSC_OFFSET                  0xA10
+
 #define ASM118x_PCIE_CAPABILITY_OFFSET      0x80
 #define ASM118x_PCIE_LINK_CONTROL_OFFSET    (ASM118x_PCIE_CAPABILITY_OFFSET + \
                                              OFFSET_OF (PCI_CAPABILITY_PCIEXP, \
@@ -39,24 +42,10 @@ RetrainAsm1184eDownstreamPort (
   IN  EFI_PCI_IO_PROTOCOL   *PciIo
   )
 {
-  UINT16                    PciVidPid[2];
   EFI_STATUS                Status;
   PCIE_CAP                  Cap;
   PCI_REG_PCIE_LINK_CONTROL LinkControl;
 
-  Status = PciIo->Pci.Read (PciIo, EfiPciIoWidthUint16, PCI_VENDOR_ID_OFFSET,
-                        ARRAY_SIZE (PciVidPid), &PciVidPid);
-  if (EFI_ERROR (Status)) {
-    DEBUG ((DEBUG_WARN, "%a: failed to read PCI vendor/product ID - %r\n",
-      __FUNCTION__, Status));
-    return;
-  }
-
-  if (PciVidPid[0] != ASMEDIA_VID ||
-      (PciVidPid[1] != ASM1182E_PID && PciVidPid[1] != ASM1184E_PID)) {
-    return;
-  }
-
   //
   // The upstream and downstream ports share the same PID/VID, so check
   // the port type. This assumes the PCIe Express capability block lives
@@ -91,6 +80,34 @@ RetrainAsm1184eDownstreamPort (
 
 STATIC
 VOID
+EnableAsm1061SpreadSpectrum (
+  IN  EFI_PCI_IO_PROTOCOL   *PciIo
+  )
+{
+  EFI_STATUS  Status;
+  UINT8       SscVal;
+
+  DEBUG ((DEBUG_INFO, "%a: enabling spread spectrum mode 0 for ASM1061\n",
+    __FUNCTION__));
+
+  // SSC mode 0~-4000 ppm, 1:1 modulation
+
+  SscVal = 0;
+  Status = PciIo->Pci.Write (PciIo, EfiPciIoWidthUint8, ASM1061_SSC_OFFSET, 1,
+                        &SscVal);
+  ASSERT_EFI_ERROR (Status);
+
+  MemoryFence ();
+  gBS->Stall (1); // delay at least 100 ns between writes of the same register
+
+  SscVal = 1;
+  Status = PciIo->Pci.Write (PciIo, EfiPciIoWidthUint8, ASM1061_SSC_OFFSET, 1,
+                        &SscVal);
+  ASSERT_EFI_ERROR (Status);
+}
+
+STATIC
+VOID
 EFIAPI
 OnPciIoProtocolNotify (
   IN EFI_EVENT      Event,
@@ -101,6 +118,7 @@ OnPciIoProtocolNotify (
   EFI_STATUS                Status;
   EFI_HANDLE                HandleBuffer;
   UINTN                     BufferSize;
+  UINT16                    PciVidPid[2];
 
   while (TRUE) {
     BufferSize = sizeof (EFI_HANDLE);
@@ -114,12 +132,37 @@ OnPciIoProtocolNotify (
                     (VOID **)&PciIo);
     ASSERT_EFI_ERROR (Status);
 
-    //
-    // The ASM1184E 4-port PCIe switch on the DeveloperBox board (and its
-    // 2-port sibling of which samples were used in development) needs a
-    // little nudge to get it to train the downstream links at Gen2 speed.
-    //
-    RetrainAsm1184eDownstreamPort (PciIo);
+    Status = PciIo->Pci.Read (PciIo, EfiPciIoWidthUint16, PCI_VENDOR_ID_OFFSET,
+                          ARRAY_SIZE (PciVidPid), &PciVidPid);
+    if (EFI_ERROR (Status)) {
+      DEBUG ((DEBUG_WARN, "%a: failed to read PCI vendor/product ID - %r\n",
+        __FUNCTION__, Status));
+      continue;
+    }
+
+    if (PciVidPid[0] != ASMEDIA_VID) {
+      continue;
+    }
+
+    switch (PciVidPid[1]) {
+    case ASM1061_PID:
+      //
+      // The ASM1061 SATA controller as integrated into the DeveloperBox design
+      // emits too much electromagnetic radiation. So enable spread spectrum
+      // mode.
+      //
+      EnableAsm1061SpreadSpectrum (PciIo);
+      break;
+    case ASM1182E_PID:
+    case ASM1184E_PID:
+      //
+      // The ASM1184E 4-port PCIe switch on the DeveloperBox board (and its
+      // 2-port sibling of which samples were used in development) needs a
+      // little nudge to get it to train the downstream links at Gen2 speed.
+      //
+      RetrainAsm1184eDownstreamPort (PciIo);
+      break;
+    }
   }
 }
 
diff --git a/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.inf b/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.inf
index 7d3b88a5b52e..766f4041c826 100644
--- a/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.inf
+++ b/Silicon/Socionext/SynQuacer/Drivers/PlatformDxe/PlatformDxe.inf
@@ -23,7 +23,7 @@ [Defines]
   ENTRY_POINT                    = PlatformDxeEntryPoint
 
 [Sources]
-  Asmedia118x.c
+  Pci.c
   PlatformDxe.c
 
 [Packages]
-- 
2.11.0