]> git.saurik.com Git - apple/xnu.git/blobdiff - pexpert/arm/pe_serial.c
xnu-7195.81.3.tar.gz
[apple/xnu.git] / pexpert / arm / pe_serial.c
index 6b9000117a1cdd805f0419fb59ee8866a9d80507..b555aa1e2a209f0bb5a77c9cab7a5b104e9db1a9 100644 (file)
@@ -10,7 +10,9 @@
 #include <kern/clock.h>
 #include <kern/debug.h>
 #include <libkern/OSBase.h>
+#include <libkern/section_keywords.h>
 #include <mach/mach_time.h>
+#include <machine/atomic.h>
 #include <machine/machine_routines.h>
 #include <pexpert/pexpert.h>
 #include <pexpert/protos.h>
@@ -26,6 +28,9 @@
 #include <pexpert/arm64/board_config.h>
 #include <arm64/proc_reg.h>
 #endif
+#if HIBERNATION
+#include <machine/pal_hibernate.h>
+#endif /* HIBERNATION */
 
 struct pe_serial_functions {
        void            (*uart_init) (void);
@@ -34,41 +39,43 @@ struct pe_serial_functions {
        void            (*td0) (int c);
        int             (*rr0) (void);
        int             (*rd0) (void);
+       struct pe_serial_functions *next;
 };
 
-static struct pe_serial_functions *gPESF;
-
-static int     uart_initted = 0;       /* 1 if init'ed */
-
-static vm_offset_t     uart_base;
+SECURITY_READ_ONLY_LATE(static struct pe_serial_functions*) gPESF = NULL;
 
+static int         uart_initted = 0;    /* 1 if init'ed */
+static vm_offset_t uart_base = 0;
 
 /*****************************************************************************/
 
-#ifdef S3CUART
+#ifdef  S3CUART
 
 static int32_t dt_pclk      = -1;
 static int32_t dt_sampling  = -1;
 static int32_t dt_ubrdiv    = -1;
 
+static void ln2410_uart_set_baud_rate(__unused int unit, uint32_t baud_rate);
+
 static void
 ln2410_uart_init(void)
 {
-       uint32_t ucon0 = 0x405; /* NCLK, No interrupts, No DMA - just polled */
+       uint32_t ucon0 = 0x405; /* NCLK, No interrupts, No DMA - just polled */
 
-       rULCON0 = 0x03;         /* 81N, not IR */
+       rULCON0 = 0x03;         /* 81N, not IR */
 
        // Override with pclk dt entry
-       if (dt_pclk != -1)
+       if (dt_pclk != -1) {
                ucon0 = ucon0 & ~0x400;
+       }
 
        rUCON0 = ucon0;
-       rUMCON0 = 0x00;         /* Clear Flow Control */
+       rUMCON0 = 0x00;         /* Clear Flow Control */
 
-       gPESF->uart_set_baud_rate(0, 115200);
+       ln2410_uart_set_baud_rate(0, 115200);
 
-       rUFCON0 = 0x03;         /* Clear & Enable FIFOs */
-       rUMCON0 = 0x01;         /* Assert RTS on UART0 */
+       rUFCON0 = 0x03;         /* Clear & Enable FIFOs */
+       rUMCON0 = 0x01;         /* Assert RTS on UART0 */
 }
 
 static void
@@ -77,35 +84,38 @@ ln2410_uart_set_baud_rate(__unused int unit, uint32_t baud_rate)
        uint32_t div = 0;
        uint32_t uart_clock = 0;
        uint32_t sample_rate = 16;
-       
-       if (baud_rate < 300)
+
+       if (baud_rate < 300) {
                baud_rate = 9600;
+       }
 
-       if (rUCON0 & 0x400)
+       if (rUCON0 & 0x400) {
                // NCLK
                uart_clock = (uint32_t)gPEClockFrequencyInfo.fix_frequency_hz;
-       else
-               // PCLK 
+       } else {
+               // PCLK
                uart_clock = (uint32_t)gPEClockFrequencyInfo.prf_frequency_hz;
+       }
 
        if (dt_sampling != -1) {
                // Use the sampling rate specified in the Device Tree
                sample_rate = dt_sampling & 0xf;
        }
-       
+
        if (dt_ubrdiv != -1) {
                // Use the ubrdiv specified in the Device Tree
                div = dt_ubrdiv & 0xffff;
        } else {
                // Calculate ubrdiv. UBRDIV = (SourceClock / (BPS * Sample Rate)) - 1
                div = uart_clock / (baud_rate * sample_rate);
-               
+
                uint32_t actual_baud = uart_clock / ((div + 0) * sample_rate);
                uint32_t baud_low    = uart_clock / ((div + 1) * sample_rate);
 
                // Adjust div to get the closest target baudrate
-               if ((baud_rate - baud_low) > (actual_baud - baud_rate))
+               if ((baud_rate - baud_low) > (actual_baud - baud_rate)) {
                        div--;
+               }
        }
 
        // Sample Rate [19:16], UBRDIV [15:0]
@@ -133,23 +143,33 @@ ln2410_rd0(void)
        return (int)rURXH0;
 }
 
-static struct pe_serial_functions ln2410_serial_functions = {
-       ln2410_uart_init, ln2410_uart_set_baud_rate,
-ln2410_tr0, ln2410_td0, ln2410_rr0, ln2410_rd0};
+SECURITY_READ_ONLY_LATE(static struct pe_serial_functions) ln2410_serial_functions =
+{
+       .uart_init = ln2410_uart_init,
+       .uart_set_baud_rate = ln2410_uart_set_baud_rate,
+       .tr0 = ln2410_tr0,
+       .td0 = ln2410_td0,
+       .rr0 = ln2410_rr0,
+       .rd0 = ln2410_rd0
+};
 
-#endif /* S3CUART */
+#endif  /* S3CUART */
 
 /*****************************************************************************/
 
+static void
+dcc_uart_init(void)
+{
+}
 
 static unsigned int
 read_dtr(void)
 {
 #ifdef __arm__
-       unsigned int    c;
-       __asm__ volatile(
-               "mrc p14, 0, %0, c0, c5\n"
-:              "=r"(c));
+       unsigned int    c;
+       __asm__ volatile (
+                 "mrc p14, 0, %0, c0, c5\n"
+ :               "=r"(c));
        return c;
 #else
        /* ARM64_TODO */
@@ -161,10 +181,10 @@ static void
 write_dtr(unsigned int c)
 {
 #ifdef __arm__
-       __asm__ volatile(
-               "mcr p14, 0, %0, c0, c5\n"
-               :
-               :"r"(c));
+       __asm__ volatile (
+                 "mcr p14, 0, %0, c0, c5\n"
+                 :
+                 :"r"(c));
 #else
        /* ARM64_TODO */
        (void)c;
@@ -208,69 +228,75 @@ dcc_rd0(void)
        return read_dtr();
 }
 
-static struct pe_serial_functions dcc_serial_functions = {
-       NULL, NULL,
-dcc_tr0, dcc_td0, dcc_rr0, dcc_rd0};
+SECURITY_READ_ONLY_LATE(static struct pe_serial_functions) dcc_serial_functions =
+{
+       .uart_init = dcc_uart_init,
+       .uart_set_baud_rate = NULL,
+       .tr0 = dcc_tr0,
+       .td0 = dcc_td0,
+       .rr0 = dcc_rr0,
+       .rd0 = dcc_rd0
+};
 
 /*****************************************************************************/
 
 #ifdef SHMCON
 
-#define CPU_CACHELINE_SIZE     (1 << MMU_CLINE)
+#define CPU_CACHELINE_SIZE      (1 << MMU_CLINE)
 
 #ifndef SHMCON_NAME
-#define SHMCON_NAME            "AP-xnu"
+#define SHMCON_NAME             "AP-xnu"
 #endif
 
-#define SHMCON_MAGIC           'SHMC'
-#define SHMCON_VERSION                 2
-#define CBUF_IN                0
-#define CBUF_OUT               1
-#define INBUF_SIZE             (panic_size / 16)
-#define FULL_ALIGNMENT         (64)
+#define SHMCON_MAGIC            'SHMC'
+#define SHMCON_VERSION          2
+#define CBUF_IN                 0
+#define CBUF_OUT                1
+#define INBUF_SIZE              (panic_size / 16)
+#define FULL_ALIGNMENT          (64)
 
-#define FLAG_CACHELINE_32      1
-#define FLAG_CACHELINE_64      2
+#define FLAG_CACHELINE_32       1
+#define FLAG_CACHELINE_64       2
 
 /* Defines to clarify the master/slave fields' use as circular buffer pointers */
-#define head_in                sidx[CBUF_IN]
-#define tail_in                midx[CBUF_IN]
-#define head_out       midx[CBUF_OUT]
-#define tail_out       sidx[CBUF_OUT]
+#define head_in         sidx[CBUF_IN]
+#define tail_in         midx[CBUF_IN]
+#define head_out        midx[CBUF_OUT]
+#define tail_out        sidx[CBUF_OUT]
 
 /* TODO: get from device tree/target */
-#define NUM_CHILDREN           5
+#define NUM_CHILDREN            5
 
 #define WRAP_INCR(len, x) do{ (x)++; if((x) >= (len)) (x) = 0; } while(0)
 #define ROUNDUP(a, b) (((a) + ((b) - 1)) & (~((b) - 1)))
 
-#define MAX(a,b) ((a) > (b) ? (a) : (b))
-#define MIN(a,b) ((a) < (b) ? (a) : (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
 
 #define shmcon_barrier() do {__asm__ volatile("dmb ish" : : : "memory");} while(0)
 
 struct shm_buffer_info {
-       uint64_t        base;
-       uint32_t        unused;
-       uint32_t        magic;
+       uint64_t        base;
+       uint32_t        unused;
+       uint32_t        magic;
 };
 
 struct shmcon_header {
-       uint32_t        magic;
-       uint8_t         version;
-       uint8_t         children;       /* number of child entries in child_ent */
-       uint16_t        flags;
-       uint64_t        buf_paddr[2];   /* Physical address for buffers (in, out) */
-       uint32_t        buf_len[2];
-       uint8_t         name[8];
+       uint32_t        magic;
+       uint8_t         version;
+       uint8_t         children;       /* number of child entries in child_ent */
+       uint16_t        flags;
+       uint64_t        buf_paddr[2];   /* Physical address for buffers (in, out) */
+       uint32_t        buf_len[2];
+       uint8_t         name[8];
 
        /* Slave-modified data - invalidate before read */
-       uint32_t        sidx[2] __attribute__((aligned (FULL_ALIGNMENT)));      /* In head, out tail */
+       uint32_t        sidx[2] __attribute__((aligned(FULL_ALIGNMENT)));       /* In head, out tail */
 
        /* Master-modified data - clean after write */
-       uint32_t        midx[2] __attribute__((aligned (FULL_ALIGNMENT)));      /* In tail, out head */ 
+       uint32_t        midx[2] __attribute__((aligned(FULL_ALIGNMENT)));       /* In tail, out head */
 
-       uint64_t        child[0];       /* Physical address of child header pointers */
+       uint64_t        child[0];       /* Physical address of child header pointers */
 };
 
 static volatile struct shmcon_header *shmcon = NULL;
@@ -280,12 +306,14 @@ static uint64_t grace = 0;
 static uint64_t full_timeout = 0;
 #endif
 
-static void shmcon_set_baud_rate(__unused int unit, __unused uint32_t baud_rate)
+static void
+shmcon_set_baud_rate(__unused int unit, __unused uint32_t baud_rate)
 {
        return;
 }
 
-static int shmcon_tr0(void)
+static int
+shmcon_tr0(void)
 {
 #ifdef SHMCON_THROTTLED
        uint32_t head = shmcon->head_out;
@@ -303,13 +331,15 @@ static int shmcon_tr0(void)
                full_timeout = mach_absolute_time() + grace;
                return 0;
        }
-       if (full_timeout > mach_absolute_time())
+       if (full_timeout > mach_absolute_time()) {
                return 0;
+       }
 
        /* Timeout - slave not really there or not keeping up */
        tail += (len / 4);
-       if (tail >= len)
+       if (tail >= len) {
                tail -= len;
+       }
        shmcon_barrier();
        shmcon->tail_out = tail;
        full_timeout = 0;
@@ -317,7 +347,8 @@ static int shmcon_tr0(void)
        return 1;
 }
 
-static void shmcon_td0(int c)
+static void
+shmcon_td0(int c)
 {
        uint32_t head = shmcon->head_out;
        uint32_t len = shmcon->buf_len[CBUF_OUT];
@@ -328,14 +359,17 @@ static void shmcon_td0(int c)
        shmcon->head_out = head;
 }
 
-static int shmcon_rr0(void)
+static int
+shmcon_rr0(void)
 {
-       if (shmcon->tail_in == shmcon->head_in)
+       if (shmcon->tail_in == shmcon->head_in) {
                return 0;
+       }
        return 1;
 }
 
-static int shmcon_rd0(void)
+static int
+shmcon_rd0(void)
 {
        int c;
        uint32_t tail = shmcon->tail_in;
@@ -348,20 +382,23 @@ static int shmcon_rd0(void)
        return c;
 }
 
-static void shmcon_init(void)
+static void
+shmcon_init(void)
 {
-       DTEntry                         entry;
-       uintptr_t                       *reg_prop;
-       volatile struct shm_buffer_info *end;
-       size_t                          i, header_size;
-       unsigned int                    size;
-       vm_offset_t                     pa_panic_base, panic_size, va_buffer_base, va_buffer_end;
+       DTEntry                         entry;
+       uintptr_t const                 *reg_prop;
+       volatile struct shm_buffer_info *end;
+       size_t                          i, header_size;
+       unsigned int                    size;
+       vm_offset_t                     pa_panic_base, panic_size, va_buffer_base, va_buffer_end;
 
-       if (kSuccess != DTLookupEntry(0, "pram", &entry))
+       if (kSuccess != SecureDTLookupEntry(0, "pram", &entry)) {
                return;
+       }
 
-       if (kSuccess != DTGetProperty(entry, "reg", (void **)&reg_prop, &size))
+       if (kSuccess != SecureDTGetProperty(entry, "reg", (void const **)&reg_prop, &size)) {
                return;
+       }
 
        pa_panic_base = reg_prop[0];
        panic_size = reg_prop[1];
@@ -386,25 +423,28 @@ static void shmcon_init(void)
                        len = shmcon->buf_len[i];
                        /* Validate buffers */
                        if ((pa_buf < pa_buffer_base) ||
-                               (pa_buf >= pa_buffer_end) ||
-                               ((pa_buf + len) > pa_buffer_end) ||
-                               (shmcon->midx[i] >= len) || /* Index out of bounds */
-                               (shmcon->sidx[i] >= len) ||
-                               (pa_buf != ROUNDUP(pa_buf, CPU_CACHELINE_SIZE)) || /* Unaligned pa_buffer */
-                               (len < 1024) ||
-                               (len > (pa_buffer_end - pa_buffer_base)) ||
-                               (shmcon->children != NUM_CHILDREN))
+                           (pa_buf >= pa_buffer_end) ||
+                           ((pa_buf + len) > pa_buffer_end) ||
+                           (shmcon->midx[i] >= len) ||     /* Index out of bounds */
+                           (shmcon->sidx[i] >= len) ||
+                           (pa_buf != ROUNDUP(pa_buf, CPU_CACHELINE_SIZE)) ||     /* Unaligned pa_buffer */
+                           (len < 1024) ||
+                           (len > (pa_buffer_end - pa_buffer_base)) ||
+                           (shmcon->children != NUM_CHILDREN)) {
                                goto validation_failure;
+                       }
                        /* Compute the VA offset of the buffer */
                        shmbuf[i] = (uint8_t *)(uintptr_t)shmcon + ((uintptr_t)pa_buf - (uintptr_t)pa_panic_base);
                }
                /* Check that buffers don't overlap */
                if ((uintptr_t)shmbuf[0] < (uintptr_t)shmbuf[1]) {
-                       if ((uintptr_t)(shmbuf[0] + shmcon->buf_len[0]) > (uintptr_t)shmbuf[1])
+                       if ((uintptr_t)(shmbuf[0] + shmcon->buf_len[0]) > (uintptr_t)shmbuf[1]) {
                                goto validation_failure;
+                       }
                } else {
-                       if ((uintptr_t)(shmbuf[1] + shmcon->buf_len[1]) > (uintptr_t)shmbuf[0])
+                       if ((uintptr_t)(shmbuf[1] + shmcon->buf_len[1]) > (uintptr_t)shmbuf[0]) {
                                goto validation_failure;
+                       }
                }
                shmcon->tail_in = shmcon->head_in; /* Clear input buffer */
                shmcon_barrier();
@@ -427,8 +467,9 @@ validation_failure:
                memset((void *)shmcon->name, ' ', sizeof(shmcon->name));
                memcpy((void *)shmcon->name, SHMCON_NAME, MIN(sizeof(shmcon->name), strlen(SHMCON_NAME)));
 #pragma clang diagnostic pop
-               for (i = 0; i < NUM_CHILDREN; i++)
+               for (i = 0; i < NUM_CHILDREN; i++) {
                        shmcon->child[0] = 0;
+               }
                shmcon_barrier();
                shmcon->magic = SHMCON_MAGIC;
        }
@@ -444,7 +485,7 @@ validation_failure:
        PE_consistent_debug_register(kDbgIdConsoleHeaderAP, pa_panic_base, panic_size);
 }
 
-static struct pe_serial_functions shmcon_serial_functions =
+SECURITY_READ_ONLY_LATE(static struct pe_serial_functions) shmcon_serial_functions =
 {
        .uart_init = shmcon_init,
        .uart_set_baud_rate = shmcon_set_baud_rate,
@@ -454,13 +495,16 @@ static struct pe_serial_functions shmcon_serial_functions =
        .rd0 = shmcon_rd0
 };
 
-int pe_shmcon_set_child(uint64_t paddr, uint32_t entry)
+int
+pe_shmcon_set_child(uint64_t paddr, uint32_t entry)
 {
-       if (shmcon == NULL)
+       if (shmcon == NULL) {
                return -1;
+       }
 
-       if (shmcon->children >= entry)
+       if (shmcon->children >= entry) {
                return -1;
+       }
 
        shmcon->child[entry] = paddr;
        return 0;
@@ -470,113 +514,24 @@ int pe_shmcon_set_child(uint64_t paddr, uint32_t entry)
 
 /*****************************************************************************/
 
-#ifdef DOCKFIFO_UART
-
-
-// Allow a 30ms stall of wall clock time before DockFIFO starts dropping characters
-#define DOCKFIFO_WR_MAX_STALL_US       (30*1000)
-
-static uint64_t prev_dockfifo_drained_time; // Last time we've seen the DockFIFO drained by an external agent
-static uint64_t prev_dockfifo_spaces;      // Previous w_stat level of the DockFIFO.
-static uint32_t dockfifo_capacity;
-static uint64_t dockfifo_stall_grace;
-
-
-//=======================
-// Local funtions
-//=======================
-
-static int dockfifo_drain_on_stall()
-{
-       // Called when DockFIFO runs out of spaces.
-       // Check if the DockFIFO reader has stalled. If so, empty the DockFIFO ourselves.
-       // Return number of bytes drained.
-
-       if (mach_absolute_time() - prev_dockfifo_drained_time >= dockfifo_stall_grace) {
-               // It's been more than DOCKFIFO_WR_MAX_STALL_US and nobody read from the FIFO
-               // Drop a character.
-               (void)rDOCKFIFO_R_DATA(DOCKFIFO_UART_READ, 1);
-               prev_dockfifo_spaces++;
-               return 1;
-       }
-       return 0;
-}
-
-
-static int dockfifo_uart_tr0(void)
-{
-       uint32_t spaces = rDOCKFIFO_W_STAT(DOCKFIFO_UART_WRITE) & 0xffff;
-       if (spaces >= dockfifo_capacity || spaces > prev_dockfifo_spaces) {
-                       // More spaces showed up. That can only mean someone read the FIFO.
-                       // Note that if the DockFIFO is empty we cannot tell if someone is listening,
-                       // we can only give them the benefit of the doubt.
-
-                       prev_dockfifo_drained_time = mach_absolute_time();
-       }
-       prev_dockfifo_spaces = spaces;
-
-       return spaces || dockfifo_drain_on_stall();
-
-}
-
-static void dockfifo_uart_td0(int c)
-{
-       rDOCKFIFO_W_DATA(DOCKFIFO_UART_WRITE, 1) = (unsigned)(c & 0xff);
-       prev_dockfifo_spaces--; // After writing a byte we have one fewer space than previously expected.
-
-}
-
-static int dockfifo_uart_rr0(void)
-{
-       return rDOCKFIFO_R_DATA(DOCKFIFO_UART_READ, 0) & 0x7f;
-}
-
-static int dockfifo_uart_rd0(void)
-{
-       return (int)((rDOCKFIFO_R_DATA(DOCKFIFO_UART_READ, 1) >> 8) & 0xff);
-}
-
-static void dockfifo_uart_init(void)
-{
-       nanoseconds_to_absolutetime(DOCKFIFO_WR_MAX_STALL_US * 1000, &dockfifo_stall_grace);
-
-       // Disable autodraining of the FIFO. We now purely manage it in software.
-       rDOCKFIFO_DRAIN(DOCKFIFO_UART_WRITE) = 0;
-
-       // Empty the DockFIFO by draining it until OCCUPANCY is 0, then measure its capacity
-       while (rDOCKFIFO_R_DATA(DOCKFIFO_UART_WRITE, 3) & 0x7F);        
-       dockfifo_capacity = rDOCKFIFO_W_STAT(DOCKFIFO_UART_WRITE) & 0xffff;
-}
-
-static struct pe_serial_functions dockfifo_uart_serial_functions =
-{
-       .uart_init = dockfifo_uart_init,
-       .uart_set_baud_rate = NULL,
-       .tr0 = dockfifo_uart_tr0,
-       .td0 = dockfifo_uart_td0,
-       .rr0 = dockfifo_uart_rr0,
-       .rd0 = dockfifo_uart_rd0
-};
-
-#endif /* DOCKFIFO_UART */
-
-/*****************************************************************************/
-
 #ifdef DOCKCHANNEL_UART
-#define DOCKCHANNEL_WR_MAX_STALL_US    (30*1000)
+#define DOCKCHANNEL_WR_MAX_STALL_US     (30*1000)
 
-static vm_offset_t     dock_agent_base;
-static uint32_t        max_dockchannel_drain_period;
-static bool            use_sw_drain;
-static uint64_t        prev_dockchannel_drained_time;  // Last time we've seen the DockChannel drained by an external agent
-static uint64_t        prev_dockchannel_spaces;        // Previous w_stat level of the DockChannel.
-static uint64_t        dockchannel_stall_grace;
+static vm_offset_t      dock_agent_base;
+static uint32_t         max_dockchannel_drain_period;
+static bool             use_sw_drain;
+static uint32_t         dock_wstat_mask;
+static uint64_t         prev_dockchannel_drained_time;  // Last time we've seen the DockChannel drained by an external agent
+static uint64_t         prev_dockchannel_spaces;        // Previous w_stat level of the DockChannel.
+static uint64_t         dockchannel_stall_grace;
+static vm_offset_t      dockchannel_uart_base = 0;
 
 //=======================
 // Local funtions
 //=======================
 
-static int dockchannel_drain_on_stall()
+static int
+dockchannel_drain_on_stall()
 {
        // Called when DockChannel runs out of spaces.
        // Check if the DockChannel reader has stalled. If so, empty the DockChannel ourselves.
@@ -585,17 +540,18 @@ static int dockchannel_drain_on_stall()
        if ((mach_absolute_time() - prev_dockchannel_drained_time) >= dockchannel_stall_grace) {
                // It's been more than DOCKCHANEL_WR_MAX_STALL_US and nobody read from the FIFO
                // Drop a character.
-               (void)rDOCKCHANNELS_DEV_RDATA1(DOCKCHANNEL_UART_CHANNEL);
-               prev_dockchannel_spaces++;
+               (void)rDOCKCHANNELS_DOCK_RDATA1(DOCKCHANNEL_UART_CHANNEL);
+               os_atomic_inc(&prev_dockchannel_spaces, relaxed);
                return 1;
        }
        return 0;
 }
 
-static int dockchannel_uart_tr0(void)
+static int
+dockchannel_uart_tr0(void)
 {
        if (use_sw_drain) {
-               uint32_t spaces = rDOCKCHANNELS_DEV_WSTAT(DOCKCHANNEL_UART_CHANNEL) & 0x1ff;
+               uint32_t spaces = rDOCKCHANNELS_DEV_WSTAT(DOCKCHANNEL_UART_CHANNEL) & dock_wstat_mask;
                if (spaces > prev_dockchannel_spaces) {
                        // More spaces showed up. That can only mean someone read the FIFO.
                        // Note that if the DockFIFO is empty we cannot tell if someone is listening,
@@ -607,50 +563,59 @@ static int dockchannel_uart_tr0(void)
                return spaces || dockchannel_drain_on_stall();
        } else {
                // Returns spaces in dockchannel fifo
-               return (rDOCKCHANNELS_DEV_WSTAT(DOCKCHANNEL_UART_CHANNEL) & 0x1ff);
+               return rDOCKCHANNELS_DEV_WSTAT(DOCKCHANNEL_UART_CHANNEL) & dock_wstat_mask;
        }
 }
 
-static void dockchannel_uart_td0(int c)
+static void
+dockchannel_uart_td0(int c)
 {
        rDOCKCHANNELS_DEV_WDATA1(DOCKCHANNEL_UART_CHANNEL) = (unsigned)(c & 0xff);
        if (use_sw_drain) {
-               prev_dockchannel_spaces--; // After writing a byte we have one fewer space than previously expected.
+               os_atomic_dec(&prev_dockchannel_spaces, relaxed); // After writing a byte we have one fewer space than previously expected.
        }
 }
 
-static int dockchannel_uart_rr0(void)
+static int
+dockchannel_uart_rr0(void)
 {
        return rDOCKCHANNELS_DEV_RDATA0(DOCKCHANNEL_UART_CHANNEL) & 0x7f;
 }
 
-static int dockchannel_uart_rd0(void)
+static int
+dockchannel_uart_rd0(void)
 {
-       return (int)((rDOCKCHANNELS_DEV_RDATA1(DOCKCHANNEL_UART_CHANNEL)>> 8) & 0xff);
+       return (int)((rDOCKCHANNELS_DEV_RDATA1(DOCKCHANNEL_UART_CHANNEL) >> 8) & 0xff);
 }
 
-static void dockchannel_uart_init(void)
+static void
+dockchannel_uart_clear_intr(void)
+{
+       rDOCKCHANNELS_AGENT_AP_INTR_CTRL &= ~(0x3);
+       rDOCKCHANNELS_AGENT_AP_INTR_STATUS |= 0x3;
+       rDOCKCHANNELS_AGENT_AP_ERR_INTR_CTRL &= ~(0x3);
+       rDOCKCHANNELS_AGENT_AP_ERR_INTR_STATUS |= 0x3;
+}
+
+static void
+dockchannel_uart_init(void)
 {
        if (use_sw_drain) {
                nanoseconds_to_absolutetime(DOCKCHANNEL_WR_MAX_STALL_US * NSEC_PER_USEC, &dockchannel_stall_grace);
        }
 
        // Clear all interrupt enable and status bits
-       rDOCKCHANNELS_AGENT_AP_INTR_CTRL &= ~(0x3);
-       rDOCKCHANNELS_AGENT_AP_INTR_STATUS |= 0x3;
-       rDOCKCHANNELS_AGENT_AP_ERR_INTR_CTRL &= ~(0x3);
-       rDOCKCHANNELS_AGENT_AP_ERR_INTR_STATUS |= 0x3;
+       dockchannel_uart_clear_intr();
 
        // Setup DRAIN timer
        rDOCKCHANNELS_DEV_DRAIN_CFG(DOCKCHANNEL_UART_CHANNEL) = max_dockchannel_drain_period;
 
        // Drain timer doesn't get loaded with value from drain period register if fifo
-       // is already full. Drop a character from the fifo.  See chapter 8 of the Cayman
-       // DockChannels specification for more details.
+       // is already full. Drop a character from the fifo.
        rDOCKCHANNELS_DOCK_RDATA1(DOCKCHANNEL_UART_CHANNEL);
 }
 
-static struct pe_serial_functions dockchannel_uart_serial_functions =
+SECURITY_READ_ONLY_LATE(static struct pe_serial_functions) dockchannel_uart_serial_functions =
 {
        .uart_init = dockchannel_uart_init,
        .uart_set_baud_rate = NULL,
@@ -662,95 +627,186 @@ static struct pe_serial_functions dockchannel_uart_serial_functions =
 
 #endif /* DOCKCHANNEL_UART */
 
+/****************************************************************************/
+#ifdef  PI3_UART
+vm_offset_t pi3_gpio_base_vaddr = 0;
+vm_offset_t pi3_aux_base_vaddr = 0;
+static int
+pi3_uart_tr0(void)
+{
+       return (int) BCM2837_GET32(BCM2837_AUX_MU_LSR_REG_V) & 0x20;
+}
+
+static void
+pi3_uart_td0(int c)
+{
+       BCM2837_PUT32(BCM2837_AUX_MU_IO_REG_V, (uint32_t) c);
+}
+
+static int
+pi3_uart_rr0(void)
+{
+       return (int) BCM2837_GET32(BCM2837_AUX_MU_LSR_REG_V) & 0x01;
+}
+
+static int
+pi3_uart_rd0(void)
+{
+       return (int) BCM2837_GET32(BCM2837_AUX_MU_IO_REG_V) & 0xff;
+}
+
+static void
+pi3_uart_init(void)
+{
+       // Scratch variable
+       uint32_t i;
+
+       // Reset mini uart registers
+       BCM2837_PUT32(BCM2837_AUX_ENABLES_V, 1);
+       BCM2837_PUT32(BCM2837_AUX_MU_CNTL_REG_V, 0);
+       BCM2837_PUT32(BCM2837_AUX_MU_LCR_REG_V, 3);
+       BCM2837_PUT32(BCM2837_AUX_MU_MCR_REG_V, 0);
+       BCM2837_PUT32(BCM2837_AUX_MU_IER_REG_V, 0);
+       BCM2837_PUT32(BCM2837_AUX_MU_IIR_REG_V, 0xC6);
+       BCM2837_PUT32(BCM2837_AUX_MU_BAUD_REG_V, 270);
+
+       i = (uint32_t)BCM2837_FSEL_REG(14);
+       // Configure GPIOs 14 & 15 for alternate function 5
+       i &= ~(BCM2837_FSEL_MASK(14));
+       i |= (BCM2837_FSEL_ALT5 << BCM2837_FSEL_OFFS(14));
+       i &= ~(BCM2837_FSEL_MASK(15));
+       i |= (BCM2837_FSEL_ALT5 << BCM2837_FSEL_OFFS(15));
+
+       BCM2837_PUT32(BCM2837_FSEL_REG(14), i);
+
+       BCM2837_PUT32(BCM2837_GPPUD_V, 0);
+
+       // Barrier before AP spinning for 150 cycles
+       __builtin_arm_isb(ISB_SY);
+
+       for (i = 0; i < 150; i++) {
+               asm volatile ("add x0, x0, xzr");
+       }
+
+       __builtin_arm_isb(ISB_SY);
+
+       BCM2837_PUT32(BCM2837_GPPUDCLK0_V, (1 << 14) | (1 << 15));
+
+       __builtin_arm_isb(ISB_SY);
+
+       for (i = 0; i < 150; i++) {
+               asm volatile ("add x0, x0, xzr");
+       }
+
+       __builtin_arm_isb(ISB_SY);
+
+       BCM2837_PUT32(BCM2837_GPPUDCLK0_V, 0);
+
+       BCM2837_PUT32(BCM2837_AUX_MU_CNTL_REG_V, 3);
+}
+
+SECURITY_READ_ONLY_LATE(static struct pe_serial_functions) pi3_uart_serial_functions =
+{
+       .uart_init = pi3_uart_init,
+       .uart_set_baud_rate = NULL,
+       .tr0 = pi3_uart_tr0,
+       .td0 = pi3_uart_td0,
+       .rr0 = pi3_uart_rr0,
+       .rd0 = pi3_uart_rd0
+};
+
+#endif /* PI3_UART */
 /*****************************************************************************/
 
+static void
+register_serial_functions(struct pe_serial_functions *fns)
+{
+       fns->next = gPESF;
+       gPESF = fns;
+}
+
 int
 serial_init(void)
 {
-       DTEntry         entryP = NULL;
-       uint32_t        prop_size, dccmode;
-       vm_offset_t     soc_base;
-       uintptr_t       *reg_prop;
-       uint32_t        *prop_value = NULL;
-       char            *serial_compat = 0;
-#ifdef SHMCON
-       uint32_t        jconmode;
-#endif
-#ifdef DOCKFIFO_UART
-       uint32_t        no_dockfifo_uart;
-#endif
-#ifdef DOCKCHANNEL_UART
-       uint32_t        no_dockchannel_uart;
-#endif
+       DTEntry         entryP = NULL;
+       uint32_t        prop_size;
+       vm_offset_t     soc_base;
+       uintptr_t const *reg_prop;
+       uint32_t const  *prop_value __unused = NULL;
+       char const      *serial_compat __unused = 0;
+       uint32_t        dccmode;
+
+       struct pe_serial_functions *fns = gPESF;
 
        if (uart_initted) {
-               gPESF->uart_init();
+               while (fns != NULL) {
+                       fns->uart_init();
+                       fns = fns->next;
+               }
                kprintf("reinit serial\n");
                return 1;
        }
+
        dccmode = 0;
-       if (PE_parse_boot_argn("dcc", &dccmode, sizeof (dccmode))) {
-               gPESF = &dcc_serial_functions;
-               uart_initted = 1;
-               return 1;
+       if (PE_parse_boot_argn("dcc", &dccmode, sizeof(dccmode))) {
+               register_serial_functions(&dcc_serial_functions);
        }
 #ifdef SHMCON
-       jconmode = 0;
+       uint32_t jconmode = 0;
        if (PE_parse_boot_argn("jcon", &jconmode, sizeof jconmode)) {
-               gPESF = &shmcon_serial_functions;
-               gPESF->uart_init();
-               uart_initted = 1;
-               return 1;
+               register_serial_functions(&shmcon_serial_functions);
        }
 #endif /* SHMCON */
 
        soc_base = pe_arm_get_soc_base_phys();
 
-       if (soc_base == 0)
+       if (soc_base == 0) {
                return 0;
+       }
 
-#ifdef DOCKFIFO_UART
-       no_dockfifo_uart = 0;
-       PE_parse_boot_argn("no-dockfifo-uart", &no_dockfifo_uart, sizeof(no_dockfifo_uart));
-       if (no_dockfifo_uart == 0) {
-               if (DTFindEntry("name", "dockfifo-uart", &entryP) == kSuccess) {
-                       DTGetProperty(entryP, "reg", (void **)&reg_prop, &prop_size);
-                       uart_base = ml_io_map(soc_base + *reg_prop, *(reg_prop + 1));
-               }
-               else {
-                       return 0;
-               }
-               gPESF = &dockfifo_uart_serial_functions;
-               gPESF->uart_init();
-               uart_initted = 1;
-               return 1;
+#ifdef PI3_UART
+       if (SecureDTFindEntry("name", "gpio", &entryP) == kSuccess) {
+               SecureDTGetProperty(entryP, "reg", (void const **)&reg_prop, &prop_size);
+               pi3_gpio_base_vaddr = ml_io_map(soc_base + *reg_prop, *(reg_prop + 1));
+       }
+       if (SecureDTFindEntry("name", "aux", &entryP) == kSuccess) {
+               SecureDTGetProperty(entryP, "reg", (void const **)&reg_prop, &prop_size);
+               pi3_aux_base_vaddr = ml_io_map(soc_base + *reg_prop, *(reg_prop + 1));
+       }
+       if ((pi3_gpio_base_vaddr != 0) && (pi3_aux_base_vaddr != 0)) {
+               register_serial_functions(&pi3_uart_serial_functions);
        }
-#endif /* DOCKFIFO_UART */
+#endif /* PI3_UART */
 
 #ifdef DOCKCHANNEL_UART
-       no_dockchannel_uart = 0;
-       // Keep the old name for boot-arg
-       PE_parse_boot_argn("no-dockfifo-uart", &no_dockchannel_uart, sizeof(no_dockchannel_uart));
-       if (no_dockchannel_uart == 0) {
-               if (DTFindEntry("name", "dockchannel-uart", &entryP) == kSuccess) {
-                       DTGetProperty(entryP, "reg", (void **)&reg_prop, &prop_size);
-                       // Should be two reg entries
-                       if (prop_size/sizeof(uintptr_t) != 4)
-                               panic("Malformed dockchannel-uart property");
-                       uart_base = ml_io_map(soc_base + *reg_prop, *(reg_prop + 1));
-                       dock_agent_base = ml_io_map(soc_base + *(reg_prop + 2), *(reg_prop + 3));
-                       gPESF = &dockchannel_uart_serial_functions;
-                       DTGetProperty(entryP, "max-aop-clk", (void **)&prop_value, &prop_size);
+       uint32_t no_dockchannel_uart = 0;
+       if (SecureDTFindEntry("name", "dockchannel-uart", &entryP) == kSuccess) {
+               SecureDTGetProperty(entryP, "reg", (void const **)&reg_prop, &prop_size);
+               // Should be two reg entries
+               if (prop_size / sizeof(uintptr_t) != 4) {
+                       panic("Malformed dockchannel-uart property");
+               }
+               dockchannel_uart_base = ml_io_map(soc_base + *reg_prop, *(reg_prop + 1));
+               dock_agent_base = ml_io_map(soc_base + *(reg_prop + 2), *(reg_prop + 3));
+               PE_parse_boot_argn("no-dockfifo-uart", &no_dockchannel_uart, sizeof(no_dockchannel_uart));
+               // Keep the old name for boot-arg
+               if (no_dockchannel_uart == 0) {
+                       register_serial_functions(&dockchannel_uart_serial_functions);
+                       SecureDTGetProperty(entryP, "max-aop-clk", (void const **)&prop_value, &prop_size);
                        max_dockchannel_drain_period = (uint32_t)((prop_value)?  (*prop_value * 0.03) : DOCKCHANNEL_DRAIN_PERIOD);
-                       DTGetProperty(entryP, "enable-sw-drain", (void **)&prop_value, &prop_size);
+                       prop_value = NULL;
+                       SecureDTGetProperty(entryP, "enable-sw-drain", (void const **)&prop_value, &prop_size);
                        use_sw_drain = (prop_value)?  *prop_value : 0;
-                       gPESF->uart_init();
-                       uart_initted = 1;
-                       return 1;
+                       prop_value = NULL;
+                       SecureDTGetProperty(entryP, "dock-wstat-mask", (void const **)&prop_value, &prop_size);
+                       dock_wstat_mask = (prop_value)?  *prop_value : 0x1ff;
+               } else {
+                       dockchannel_uart_clear_intr();
                }
                // If no dockchannel-uart is found in the device tree, fall back
                // to looking for the traditional UART serial console.
        }
+
 #endif /* DOCKCHANNEL_UART */
 
        /*
@@ -758,51 +814,78 @@ serial_init(void)
         * If we don't find it there, look for "uart0" and "uart1".
         */
 
-       if (DTFindEntry("boot-console", NULL, &entryP) == kSuccess) {
-               DTGetProperty(entryP, "reg", (void **)&reg_prop, &prop_size);
+       if (SecureDTFindEntry("boot-console", NULL, &entryP) == kSuccess) {
+               SecureDTGetProperty(entryP, "reg", (void const **)&reg_prop, &prop_size);
                uart_base = ml_io_map(soc_base + *reg_prop, *(reg_prop + 1));
-               if (serial_compat == 0)
-                       DTGetProperty(entryP, "compatible", (void **)&serial_compat, &prop_size);
-       } else if (DTFindEntry("name", "uart0", &entryP) == kSuccess) {
-               DTGetProperty(entryP, "reg", (void **)&reg_prop, &prop_size);
+               if (serial_compat == 0) {
+                       SecureDTGetProperty(entryP, "compatible", (void const **)&serial_compat, &prop_size);
+               }
+       } else if (SecureDTFindEntry("name", "uart0", &entryP) == kSuccess) {
+               SecureDTGetProperty(entryP, "reg", (void const **)&reg_prop, &prop_size);
                uart_base = ml_io_map(soc_base + *reg_prop, *(reg_prop + 1));
-               if (serial_compat == 0)
-                       DTGetProperty(entryP, "compatible", (void **)&serial_compat, &prop_size);
-       } else if (DTFindEntry("name", "uart1", &entryP) == kSuccess) {
-               DTGetProperty(entryP, "reg", (void **)&reg_prop, &prop_size);
+               if (serial_compat == 0) {
+                       SecureDTGetProperty(entryP, "compatible", (void const **)&serial_compat, &prop_size);
+               }
+       } else if (SecureDTFindEntry("name", "uart1", &entryP) == kSuccess) {
+               SecureDTGetProperty(entryP, "reg", (void const **)&reg_prop, &prop_size);
                uart_base = ml_io_map(soc_base + *reg_prop, *(reg_prop + 1));
-               if (serial_compat == 0)
-                       DTGetProperty(entryP, "compatible", (void **)&serial_compat, &prop_size);
+               if (serial_compat == 0) {
+                       SecureDTGetProperty(entryP, "compatible", (void const **)&serial_compat, &prop_size);
+               }
        }
-#ifdef S3CUART
+#ifdef  S3CUART
        if (NULL != entryP) {
-               DTGetProperty(entryP, "pclk", (void **)&prop_value, &prop_size);
-               if (prop_value) dt_pclk = *prop_value;
+               SecureDTGetProperty(entryP, "pclk", (void const **)&prop_value, &prop_size);
+               if (prop_value) {
+                       dt_pclk = *prop_value;
+               }
 
                prop_value = NULL;
-               DTGetProperty(entryP, "sampling", (void **)&prop_value, &prop_size);
-               if (prop_value) dt_sampling = *prop_value;
+               SecureDTGetProperty(entryP, "sampling", (void const **)&prop_value, &prop_size);
+               if (prop_value) {
+                       dt_sampling = *prop_value;
+               }
 
                prop_value = NULL;
-               DTGetProperty(entryP, "ubrdiv", (void **)&prop_value, &prop_size);
-               if (prop_value) dt_ubrdiv = *prop_value;
-       }
-       if (!strcmp(serial_compat, "uart,16550"))
-               gPESF = &ln2410_serial_functions;
-       else if (!strcmp(serial_compat, "uart-16550"))
-               gPESF = &ln2410_serial_functions;
-       else if (!strcmp(serial_compat, "uart,s5i3000"))
-               gPESF = &ln2410_serial_functions;
-       else if (!strcmp(serial_compat, "uart-1,samsung"))
-               gPESF = &ln2410_serial_functions;
-#elif  defined (ARM_BOARD_CONFIG_MV88F6710)
-       if (!strcmp(serial_compat, "uart16x50,mmio"))
-               gPESF = &uart16x50_serial_functions;
-#endif
-       else
+               SecureDTGetProperty(entryP, "ubrdiv", (void const **)&prop_value, &prop_size);
+               if (prop_value) {
+                       dt_ubrdiv = *prop_value;
+               }
+       }
+
+       if (serial_compat) {
+               if (!strcmp(serial_compat, "uart,16550")) {
+                       register_serial_functions(&ln2410_serial_functions);
+               } else if (!strcmp(serial_compat, "uart-16550")) {
+                       register_serial_functions(&ln2410_serial_functions);
+               } else if (!strcmp(serial_compat, "uart,s5i3000")) {
+                       register_serial_functions(&ln2410_serial_functions);
+               } else if (!strcmp(serial_compat, "uart-1,samsung")) {
+                       register_serial_functions(&ln2410_serial_functions);
+               }
+       }
+#endif /* S3CUART */
+
+       if (gPESF == NULL) {
                return 0;
+       }
+
+       fns = gPESF;
+       while (fns != NULL) {
+               fns->uart_init();
+               fns = fns->next;
+       }
 
-       gPESF->uart_init();
+#if HIBERNATION
+       /* hibernation needs to know the UART register addresses since it can't directly use this serial driver */
+       if (dockchannel_uart_base) {
+               gHibernateGlobals.dockChannelRegBase = ml_vtophys(dockchannel_uart_base);
+               gHibernateGlobals.dockChannelWstatMask = dock_wstat_mask;
+       }
+       if (uart_base) {
+               gHibernateGlobals.hibUartRegBase = ml_vtophys(uart_base);
+       }
+#endif /* HIBERNATION */
 
        uart_initted = 1;
 
@@ -812,19 +895,28 @@ serial_init(void)
 void
 uart_putc(char c)
 {
-       if (uart_initted) {
-               while (!gPESF->tr0());  /* Wait until THR is empty. */
-               gPESF->td0(c);
+       struct pe_serial_functions *fns = gPESF;
+       while (fns != NULL) {
+               while (!fns->tr0()) {
+#if __arm64__                           /* on arm64, we have a WFE timeout, so no need to hot-poll here */
+                       __builtin_arm_wfe()
+#endif
+                       ;               /* Wait until THR is empty. */
+               }
+               fns->td0(c);
+               fns = fns->next;
        }
 }
 
 int
 uart_getc(void)
-{                              /* returns -1 if no data available */
-       if (uart_initted) {
-               if (!gPESF->rr0())
-                       return -1;      /* Receive data read */
-               return gPESF->rd0();
+{                               /* returns -1 if no data available */
+       struct pe_serial_functions *fns = gPESF;
+       while (fns != NULL) {
+               if (fns->rr0()) {
+                       return fns->rd0();
+               }
+               fns = fns->next;
        }
        return -1;
 }