[phantom] Unhalt/halt all PEGs during driver startup/shutdown

A hardware bug means that reads through the expansion ROM BAR can
return corrupted data if the PEGs are running.  This breaks platforms
that re-read the expansion ROM after invoking gPXE code, such as IBM
blade servers.

Halt PEGs during driver shutdown, and unhalt PEGs during driver
startup if we detect that this is not the first startup since
power-on.

src/drivers/net/phantom/phantom.c

 		{ UNM_CRB_BLK_CAM,	0x416 },
 		{ UNM_CRB_BLK_ROMUSB,	0x421 },
 		{ UNM_CRB_BLK_TEST,	0x295 },
+		{ UNM_CRB_BLK_PEG_0,	0x340 },
+		{ UNM_CRB_BLK_PEG_1,	0x341 },
+		{ UNM_CRB_BLK_PEG_2,	0x342 },
+		{ UNM_CRB_BLK_PEG_3,	0x343 },
+		{ UNM_CRB_BLK_PEG_4,	0x34b },
 	};
 	unsigned int block = UNM_CRB_BLK ( reg );
 	unsigned long offset = UNM_CRB_OFFSET ( reg );
 	return 0;
 }
 
+/**
+ * Halt all PEGs
+ *
+ * @v phantom		Phantom NIC
+ */
+static void phantom_halt_pegs ( struct phantom_nic *phantom ) {
+	phantom_writel ( phantom, 1, UNM_PEG_0_HALT );
+	phantom_writel ( phantom, 1, UNM_PEG_1_HALT );
+	phantom_writel ( phantom, 1, UNM_PEG_2_HALT );
+	phantom_writel ( phantom, 1, UNM_PEG_3_HALT );
+	phantom_writel ( phantom, 1, UNM_PEG_4_HALT );
+}
+
+/**
+ * Unhalt all PEGs
+ *
+ * @v phantom		Phantom NIC
+ */
+static void phantom_unhalt_pegs ( struct phantom_nic *phantom ) {
+	uint32_t halt_status;
+
+	halt_status = phantom_readl ( phantom, UNM_PEG_0_HALT_STATUS );
+	phantom_writel ( phantom, halt_status, UNM_PEG_0_HALT_STATUS );
+	halt_status = phantom_readl ( phantom, UNM_PEG_1_HALT_STATUS );
+	phantom_writel ( phantom, halt_status, UNM_PEG_1_HALT_STATUS );
+	halt_status = phantom_readl ( phantom, UNM_PEG_2_HALT_STATUS );
+	phantom_writel ( phantom, halt_status, UNM_PEG_2_HALT_STATUS );
+	halt_status = phantom_readl ( phantom, UNM_PEG_3_HALT_STATUS );
+	phantom_writel ( phantom, halt_status, UNM_PEG_3_HALT_STATUS );
+	halt_status = phantom_readl ( phantom, UNM_PEG_4_HALT_STATUS );
+	phantom_writel ( phantom, halt_status, UNM_PEG_4_HALT_STATUS );
+}
+
 /**
  * Initialise the Phantom command PEG
  *
 	if ( cmdpeg_state == UNM_NIC_REG_CMDPEG_STATE_INITIALIZE_ACK ) {
 		DBGC ( phantom, "Phantom %p command PEG already initialized\n",
 		       phantom );
+		/* Unhalt the PEGs.  Previous firmware (e.g. BOFM) may
+		 * have halted the PEGs to prevent internal bus
+		 * collisions when the BIOS re-reads the expansion ROM.
+		 */
+		phantom_unhalt_pegs ( phantom );
 		return 0;
 	}
 
 	for ( ; i >= 0 ; i-- )
 		unregister_netdev ( phantom->netdev[i] );
  err_init_rcvpeg:
+	phantom_halt_pegs ( phantom );
  err_init_cmdpeg:
 	free_dma ( phantom->dma_buf, sizeof ( *(phantom->dma_buf) ) );
 	phantom->dma_buf = NULL;
 
 	for ( i = ( phantom->num_ports - 1 ) ; i >= 0 ; i-- )
 		unregister_netdev ( phantom->netdev[i] );
+	phantom_halt_pegs ( phantom );
 	free_dma ( phantom->dma_buf, sizeof ( *(phantom->dma_buf) ) );
 	phantom->dma_buf = NULL;
 	for ( i = ( phantom->num_ports - 1 ) ; i >= 0 ; i-- ) {

src/drivers/net/phantom/phantom.h

 	UNM_CRB_BLK_CAM		= 0x22,
 	UNM_CRB_BLK_ROMUSB	= 0x33,
 	UNM_CRB_BLK_TEST	= 0x02,
+	UNM_CRB_BLK_PEG_0	= 0x11,
+	UNM_CRB_BLK_PEG_1	= 0x12,
+	UNM_CRB_BLK_PEG_2	= 0x13,
+	UNM_CRB_BLK_PEG_3	= 0x14,
+	UNM_CRB_BLK_PEG_4	= 0x0f,
 };
 #define UNM_CRB_BASE(blk)		( (blk) << 20 )
 #define UNM_CRB_BLK(reg)		( (reg) >> 20 )
 #define UNM_TEST_RDDATA_LO		( UNM_CRB_TEST + 0x000a8 )
 #define UNM_TEST_RDDATA_HI		( UNM_CRB_TEST + 0x000ac )
 
+#define UNM_CRB_PEG_0			UNM_CRB_BASE ( UNM_CRB_BLK_PEG_0 )
+#define UNM_PEG_0_HALT_STATUS		( UNM_CRB_PEG_0 + 0x00030 )
+#define UNM_PEG_0_HALT			( UNM_CRB_PEG_0 + 0x0003c )
+
+#define UNM_CRB_PEG_1			UNM_CRB_BASE ( UNM_CRB_BLK_PEG_1 )
+#define UNM_PEG_1_HALT_STATUS		( UNM_CRB_PEG_1 + 0x00030 )
+#define UNM_PEG_1_HALT			( UNM_CRB_PEG_1 + 0x0003c )
+
+#define UNM_CRB_PEG_2			UNM_CRB_BASE ( UNM_CRB_BLK_PEG_2 )
+#define UNM_PEG_2_HALT_STATUS		( UNM_CRB_PEG_2 + 0x00030 )
+#define UNM_PEG_2_HALT			( UNM_CRB_PEG_2 + 0x0003c )
+
+#define UNM_CRB_PEG_3			UNM_CRB_BASE ( UNM_CRB_BLK_PEG_3 )
+#define UNM_PEG_3_HALT_STATUS		( UNM_CRB_PEG_3 + 0x00030 )
+#define UNM_PEG_3_HALT			( UNM_CRB_PEG_3 + 0x0003c )
+
+#define UNM_CRB_PEG_4			UNM_CRB_BASE ( UNM_CRB_BLK_PEG_4 )
+#define UNM_PEG_4_HALT_STATUS		( UNM_CRB_PEG_4 + 0x00030 )
+#define UNM_PEG_4_HALT			( UNM_CRB_PEG_4 + 0x0003c )
+
 /******************************************************************************
  *
  * Flash layout