3.16.39. OS Lock Status Register, ETMOSLSR

The ETMOSLSR characteristics are:

Purpose
  • Used to find whether the PTM trace registers are locked.

  • Can be used to find whether PTM trace register locking is implemented.

Usage constraints

There are no usage constraints.

Configurations

Available in all PTM implementations.

Attributes

See the register summary in Table 3.16.

Figure 3.44 shows the ETMOSLSR bit assignments.

Figure 3.44. ETMOSLSR bit assignments

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Table 3.53 shows the ETMOSLSR bit assignments.

Table 3.53. ETMOSLSR bit assignments

Bits

Description

[31:4]

Reserved, RAZ.

[3]

Lock access mechanism indicator.

In PFTv1.0, this bit is always Read-As-Zero.

From PFTv1.1, this bit is used together with bit [0] to indicate whether the OS lock is implemented. SeeTable 3.54 and Table 3.81 for information on how these bits are used.

[2]

32-bit access bit.

This bit is always Read-As-Zero, indicating that a 32-bit access is required to operate the ETMOSLSR.

[1]

Locked bit. The possible values of this bit are:

0

PTM trace registers are not locked.

1

PTM trace registers are locked. Any access to these registers returns a slave-generated error response.

In PFTv1.0, the reset value of this field is implementation defined.

From PFTv1.1, if the OS Lock is implemented, this field is set from a PTM reset..

[0]

Lock access mechanism indicator.

In PFTv1.0, the possible values of this bit are:

0

OS Lock and OS Save and Restore registers are not implemented. In this case, bits [31:0] of the OS Lock Status Register are RAZ.

1

OS Lock and OS Save and Restore registers are implemented and it is possible to set the OS Lock for this macrocell, to lock the PTM trace registers.

From PFTv1.1, this bit is used together with bit [3]. SeeTable 3.54 and Table 3.81 for information on how these bits are used.

The reset value of this field is implementation defined.


Table 3.54 shows how bits [3] and [0] are used to determine whether the OS lock is implemented.

Table 3.54. OS lock implementation

ETMOSLSR[3]ETMOSLSR[0]OS lock implemented
00No
01Yes
10Yes
11Reserved

If a read of the OS Lock Status Register returns zero, OS Locking is not implemented.

See Power-down support for more information about OS Locking.

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