AWAC-PDM control and status registers.

devices/amic.cpp

@@ -44,6 +44,7 @@ AMIC::AMIC()
     }
 
     this->viacuda = std::unique_ptr<ViaCuda> (new ViaCuda());
+    this->awacs   = std::unique_ptr<AwacDevicePdm> (new AwacDevicePdm());
 }
 
 bool AMIC::supports_type(HWCompType type) {
@@ -60,7 +61,12 @@ uint32_t AMIC::read(uint32_t reg_start, uint32_t offset, int size)
         return this->viacuda->read(offset >> 9);
     }
 
-    LOG_F(INFO, "AMIC read!");
+    switch(offset) {
+    case AMICReg::Snd_Stat_0:
+    case AMICReg::Snd_Stat_1:
+    case AMICReg::Snd_Stat_2:
+        return (this->awacs->read_stat() >> (offset &  3 * 8)) & 0xFF;
+    }
     return 0;
 }
 
@@ -72,6 +78,19 @@ void AMIC::write(uint32_t reg_start, uint32_t offset, uint32_t value, int size)
     }
 
     switch(offset) {
+    case AMICReg::Snd_Cntl_0:
+    case AMICReg::Snd_Cntl_1:
+    case AMICReg::Snd_Cntl_2:
+        // remember values of sound control registers
+        this->imm_snd_regs[offset & 3] = value;
+        // transfer control information to the sound codec when ready
+        if ((this->imm_snd_regs[0] & 0xC0) == PDM_SND_CNTL_VALID) {
+            this->awacs->write_ctrl(
+                (this->imm_snd_regs[1] >> 4) | (this->imm_snd_regs[0] & 0x3F),
+                ((this->imm_snd_regs[1] & 0xF) << 8) | this->imm_snd_regs[2]
+            );
+        }
+        break;
     case AMICReg::Snd_Out_Cntl:
         LOG_F(INFO, "AMIC Sound Out Ctrl updated, val=%x", value);
         break;

devices/amic.h

@@ -24,6 +24,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #ifndef AMIC_H
 #define AMIC_H
 
+#include "awacs.h"
 #include "mmiodevice.h"
 #include "viacuda.h"
 #include <cinttypes>
@@ -31,9 +32,15 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 /* AMIC DMA registers offsets from AMIC base (0x50F00000). */
 enum AMICReg : uint32_t {
-    // Sound control registers
-    Snd_Out_Cntl        = 0x14010,
-    Snd_In_Cntl         = 0x14011,
+    // Audio codec control registers
+    Snd_Cntl_0          = 0x14000, // audio codec control register 0
+    Snd_Cntl_1          = 0x14001, // audio codec control register 1
+    Snd_Cntl_2          = 0x14002, // audio codec control register 2
+    Snd_Stat_0          = 0x14004, // audio codec status register 0
+    Snd_Stat_1          = 0x14005, // audio codec status register 1
+    Snd_Stat_2          = 0x14006, // audio codec status register 2
+    Snd_Out_Cntl        = 0x14010, // audio codec output DMA control register
+    Snd_In_Cntl         = 0x14011, // audio codec input DMA control register
 
     // VIA2 registers
     VIA2_Slot_IER       = 0x26012,
@@ -70,7 +77,10 @@ protected:
     void dma_reg_write(uint32_t offset, uint32_t value, int size);
 
 private:
-    std::unique_ptr<ViaCuda> viacuda;
+    uint8_t imm_snd_regs[4]; // temporary storage for sound control registers
+
+    std::unique_ptr<ViaCuda>        viacuda;
+    std::unique_ptr<AwacDevicePdm>  awacs;
 };
 
 #endif // AMIC_H

devices/awacs.cpp

@@ -287,3 +287,25 @@ void AWACDevice::dma_start()
 void AWACDevice::dma_end()
 {
 }
+
+//=========================== PDM-style AWAC =================================
+AwacDevicePdm::AwacDevicePdm()
+{
+}
+
+uint32_t AwacDevicePdm::read_stat()
+{
+    LOG_F(INFO, "AWAC-PDM status requested!");
+    return 0;
+}
+
+void AwacDevicePdm::write_ctrl(uint32_t addr, uint16_t value)
+{
+    LOG_F(INFO, "AWAC-PDM control updated, address=0x%X, val=0x%X", addr, value);
+
+    if (addr <= 4) {
+        this->ctrl_regs[addr] = value;
+    } else {
+        LOG_F(ERROR, "AWAC-PDM: invalid control register address %d!", addr);
+    }
+}

devices/awacs.h

@@ -41,8 +41,8 @@ enum {
 };
 
 /** AWAC manufacturer and revision. */
-#define AWAC_MAKER_CRYSTAL 1
-#define AWAC_REV_SCREAMER 3
+#define AWAC_MAKER_CRYSTAL  1
+#define AWAC_REV_SCREAMER   3
 
 /** Apple source calls this kValidData but doesn't explain
     what it actually means. It seems like it's used to check
@@ -136,5 +136,25 @@ private:
     DMAChannel  *dma_out_ch;
 };
 
+/** AWAC PDM-style definitions. */
+
+// PDM HWInit source defines two constants: kExpBit = 0x80 and kCmdBit = 0x40
+// I don't know what they means but it seems that their combination will
+// cause sound control parameters to be transferred to the sound chip.
+#define PDM_SND_CNTL_VALID  0xC0
+
+/** AWAC PDM-style sound codec. */
+class AwacDevicePdm {
+public:
+    AwacDevicePdm();
+    ~AwacDevicePdm() = default;
+
+    uint32_t read_stat(void);
+    void write_ctrl(uint32_t addr, uint16_t value);
+
+private:
+    uint16_t    ctrl_regs[5]; // 12-bit wide control registers
+};
+
 
 #endif /* AWAC_H */