* use either SWD or JTAG, and is called SWJ-DP. The most common type of AP
* is used to access memory mapped resources and is called a MEM-AP. Also a
* JTAG-AP is also defined, bridging to JTAG resources; those are uncommon.
+ *
+ * @todo Remove modality (queued/nonqueued, via DAP trans_mode) from all
+ * procedure interfaces. Modal programming interfaces are very error prone.
+ * Procedures should be either queued, or synchronous. Otherwise input
+ * and output constraints are context-sensitive, and it's hard to know
+ * what a block of code will do just by reading it.
*/
/*
reg_addr, DPAP_READ, 0, value);
}
-int dap_ap_select(struct swjdp_common *swjdp,uint8_t apsel)
+/**
+ * Select one of the APs connected to the specified DAP. The
+ * selection is implicitly used with future AP transactions.
+ * This is a NOP if the specified AP is already selected.
+ *
+ * @param swjdp The DAP
+ * @param apsel Number of the AP to (implicitly) use with further
+ * transactions. This normally identifies a MEM-AP.
+ */
+void dap_ap_select(struct swjdp_common *swjdp,uint8_t apsel)
{
uint32_t select;
select = (apsel << 24) & 0xFF000000;
swjdp->ap_csw_value = -1;
swjdp->ap_tar_value = -1;
}
-
- return ERROR_OK;
}
static int dap_dp_bankselect(struct swjdp_common *swjdp, uint32_t ap_reg)
swjdp->dp_select_value = select;
}
+ /* FIXME return any fault code from write() call */
return ERROR_OK;
}
scan_inout_check(swjdp, JTAG_DP_APACC, reg_addr,
DPAP_WRITE, out_value_buf, NULL);
+ /* FIXME return fault code from above calls */
return ERROR_OK;
}
-int dap_ap_write_reg_u32(struct swjdp_common *swjdp, uint32_t reg_addr, uint32_t value)
+/**
+ * Write an AP register value.
+ * This is synchronous iff the mode is set to ATOMIC, in which
+ * case any queued transactions are flushed.
+ *
+ * @param swjdp The DAP whose currently selected AP will be written.
+ * @param reg_addr Eight bit AP register address.
+ * @param value Word to be written at reg_addr
+ *
+ * @return In synchronous mode: ERROR_OK for success, and the register holds
+ * the specified value; else a fault code. In asynchronous mode, a status
+ * code reflecting whether the transaction was properly queued.
+ */
+int dap_ap_write_reg_u32(struct swjdp_common *swjdp,
+ uint32_t reg_addr, uint32_t value)
{
uint8_t out_value_buf[4];
scan_inout_check(swjdp, JTAG_DP_APACC, reg_addr,
DPAP_WRITE, out_value_buf, NULL);
+ /* FIXME return any fault code from above calls */
return ERROR_OK;
}
-int dap_ap_read_reg_u32(struct swjdp_common *swjdp, uint32_t reg_addr, uint32_t *value)
+/**
+ * Read an AP register value.
+ * This is synchronous iff the mode is set to ATOMIC, in which
+ * case any queued transactions are flushed.
+ *
+ * @param swjdp The DAP whose currently selected AP will be read.
+ * @param reg_addr Eight bit AP register address.
+ * @param value Points to where the 32-bit (little-endian) word will be stored.
+ *
+ * @return In synchronous mode: ERROR_OK for success, and *value holds
+ * the specified value; else a fault code. In asynchronous mode, a status
+ * code reflecting whether the transaction was properly queued.
+ */
+int dap_ap_read_reg_u32(struct swjdp_common *swjdp,
+ uint32_t reg_addr, uint32_t *value)
{
dap_dp_bankselect(swjdp, reg_addr);
scan_inout_check_u32(swjdp, JTAG_DP_APACC, reg_addr,
DPAP_READ, 0, value);
+ /* FIXME return any fault code from above calls */
return ERROR_OK;
}
/**
* Set up transfer parameters for the currently selected MEM-AP.
+ * This is synchronous iff the mode is set to ATOMIC, in which
+ * case any queued transactions are flushed.
+ *
* Subsequent transfers using registers like AP_REG_DRW or AP_REG_BD2
* initiate data reads or writes using memory or peripheral addresses.
* If the CSW is configured for it, the TAR may be automatically
* matches the cached value, the register is not changed.
* @param tar MEM-AP Transfer Address Register (TAR) to assign. If this
* matches the cached address, the register is not changed.
+ *
+ * @return In synchronous mode: ERROR_OK for success, and the AP is set
+ * up as requested else a fault code. In asynchronous mode, a status
+ * code reflecting whether the transaction was properly queued.
*/
int dap_setup_accessport(struct swjdp_common *swjdp, uint32_t csw, uint32_t tar)
{
if (csw != swjdp->ap_csw_value)
{
/* LOG_DEBUG("DAP: Set CSW %x",csw); */
+ /* FIXME if this call fails, fail this procedure! */
dap_ap_write_reg_u32(swjdp, AP_REG_CSW, csw);
swjdp->ap_csw_value = csw;
}
if (tar != swjdp->ap_tar_value)
{
/* LOG_DEBUG("DAP: Set TAR %x",tar); */
+ /* FIXME if this call fails, fail this procedure! */
dap_ap_write_reg_u32(swjdp, AP_REG_TAR, tar);
swjdp->ap_tar_value = tar;
}
return ERROR_OK;
}
-/*****************************************************************************
-* *
-* mem_ap_read_u32(struct swjdp_common *swjdp, uint32_t address, uint32_t *value) *
-* *
-* Read a uint32_t value from memory or system register *
-* Functionally equivalent to target_read_u32(target, address, uint32_t *value), *
-* but with less overhead *
-*****************************************************************************/
-int mem_ap_read_u32(struct swjdp_common *swjdp, uint32_t address, uint32_t *value)
+/**
+ * Asynchronous (queued) read of a word from memory or a system register.
+ *
+ * @param swjdp The DAP connected to the MEM-AP performing the read.
+ * @param address Address of the 32-bit word to read; it must be
+ * readable by the currently selected MEM-AP.
+ * @param value points to where the word will be stored when the
+ * transaction queue is flushed (assuming no errors).
+ *
+ * @return ERROR_OK for success. Otherwise a fault code.
+ */
+int mem_ap_read_u32(struct swjdp_common *swjdp, uint32_t address,
+ uint32_t *value)
{
swjdp->trans_mode = TRANS_MODE_COMPOSITE;
- dap_setup_accessport(swjdp, CSW_32BIT | CSW_ADDRINC_OFF, address & 0xFFFFFFF0);
+ /* Use banked addressing (REG_BDx) to avoid some link traffic
+ * (updating TAR) when reading several consecutive addresses.
+ */
+ dap_setup_accessport(swjdp, CSW_32BIT | CSW_ADDRINC_OFF,
+ address & 0xFFFFFFF0);
dap_ap_read_reg_u32(swjdp, AP_REG_BD0 | (address & 0xC), value);
+ /* FIXME return any fault code from above calls */
return ERROR_OK;
}
-int mem_ap_read_atomic_u32(struct swjdp_common *swjdp, uint32_t address, uint32_t *value)
+/**
+ * Synchronous read of a word from memory or a system register.
+ * As a side effect, this flushes any queued transactions.
+ *
+ * @param swjdp The DAP connected to the MEM-AP performing the read.
+ * @param address Address of the 32-bit word to read; it must be
+ * readable by the currently selected MEM-AP.
+ * @param value points to where the result will be stored.
+ *
+ * @return ERROR_OK for success; *value holds the result.
+ * Otherwise a fault code.
+ */
+int mem_ap_read_atomic_u32(struct swjdp_common *swjdp, uint32_t address,
+ uint32_t *value)
{
mem_ap_read_u32(swjdp, address, value);
+ /* FIXME return any fault code from above call */
return jtagdp_transaction_endcheck(swjdp);
}
-/*****************************************************************************
-* *
-* mem_ap_write_u32(struct swjdp_common *swjdp, uint32_t address, uint32_t value) *
-* *
-* Write a uint32_t value to memory or memory mapped register *
-* *
-*****************************************************************************/
-int mem_ap_write_u32(struct swjdp_common *swjdp, uint32_t address, uint32_t value)
+/**
+ * Asynchronous (queued) write of a word to memory or a system register.
+ *
+ * @param swjdp The DAP connected to the MEM-AP.
+ * @param address Address to be written; it must be writable by
+ * the currently selected MEM-AP.
+ * @param value Word that will be written to the address when transaction
+ * queue is flushed (assuming no errors).
+ *
+ * @return ERROR_OK for success. Otherwise a fault code.
+ */
+int mem_ap_write_u32(struct swjdp_common *swjdp, uint32_t address,
+ uint32_t value)
{
swjdp->trans_mode = TRANS_MODE_COMPOSITE;
- dap_setup_accessport(swjdp, CSW_32BIT | CSW_ADDRINC_OFF, address & 0xFFFFFFF0);
+ /* Use banked addressing (REG_BDx) to avoid some link traffic
+ * (updating TAR) when writing several consecutive addresses.
+ */
+ dap_setup_accessport(swjdp, CSW_32BIT | CSW_ADDRINC_OFF,
+ address & 0xFFFFFFF0);
dap_ap_write_reg_u32(swjdp, AP_REG_BD0 | (address & 0xC), value);
+ /* FIXME return any fault code from above calls */
return ERROR_OK;
}
-int mem_ap_write_atomic_u32(struct swjdp_common *swjdp, uint32_t address, uint32_t value)
+/**
+ * Synchronous write of a word to memory or a system register.
+ * As a side effect, this flushes any queued transactions.
+ *
+ * @param swjdp The DAP connected to the MEM-AP.
+ * @param address Address to be written; it must be writable by
+ * the currently selected MEM-AP.
+ * @param value Word that will be written.
+ *
+ * @return ERROR_OK for success; the data was written. Otherwise a fault code.
+ */
+int mem_ap_write_atomic_u32(struct swjdp_common *swjdp, uint32_t address,
+ uint32_t value)
{
mem_ap_write_u32(swjdp, address, value);
+ /* FIXME return any fault code from above call */
return jtagdp_transaction_endcheck(swjdp);
}
}
/**
- * Initialize a DAP.
+ * Initialize a DAP. This sets up the power domains, prepares the DP
+ * for further use, and arranges to use AP #0 for all AP operations
+ * until dap_ap-select() changes that policy.
+ *
+ * @param swjdp The DAP being initialized.
*
* @todo Rename this. We also need an initialization scheme which account
* for SWD transports not just JTAG; that will need to address differences
projects / fw / openocd / commitdiff