/* GRLIB AMBA Plug&Play information scanning implemented without * using memory (stack) and one register window. The code scan * the PnP info and inserts the AHB bridges/buses into register * i0-i5. * The code support * - up to 6 AHB buses * - multiple APB buses * - support for AHB2AHB & L2CACHE bridges * * (C) Copyright 2010, 2015 * Daniel Hellstrom, Cobham Gaisler, daniel@gaisler.com. * * SPDX-License-Identifier: GPL-2.0+ */ #include .seg "text" .globl _nomem_amba_init .globl _nomem_ambapp_find_buses .globl _nomem_find_apb .globl _nomem_find_ahb /* Overview * ======== * * _nomem_amba_init - Init AMBA bus and calls _nomem_ambapp_find_buses * _nomem_ambapp_find_buses - Scan AMBA PnP info for AHB buses/bridges and * place them in i0-i5, see below * _nomem_find_apb - Find one APB device identified by VENDOR:DEVICE * ID and an index. * _nomem_find_ahb - Find one AHB Master or Slave device identified * by VENDOR:DEVICE ID and an index. * init_ahb_bridges - Local function. Clears i0-i5 * insert_ahb_bridge - Local function. Insert a new AHB bus into first * free register in i0-i5. It also checks that the * bus has not already been added. * get_ahb_bridge - Local function. Get AHB bus from registers, * return register iN, where N is defined by o0. * * The _nomem_find_apb and _nomem_find_ahb function requires that i0-i5 * are populated with the AHB buses of the system. The registers are * initialized by _nomem_ambapp_find_buses. * * AHB Bus result and requirements of i0-i5 * ======================================== * * i0: AHB BUS0 IOAREA, no parent bus * i1: AHB BUS1 IOAREA, parent bus is always i0 (AHB BUS0) and bridge address * i2: AHB BUS2 IOAREA, 3-bit parent bus number and bridge address * i3: AHB BUS3 IOAREA, 3-bit parent bus number and bridge address * i4: AHB BUS4 IOAREA, 3-bit parent bus number and bridge address * i5: AHB BUS5 IOAREA, 3-bit parent bus number and bridge address * * AHB BUS * ------- * Bits 31-20 (0xfff00000) contain the found bus I/O Area (AHB PnP area). * * 3-bit Parent bus * ---------------- * Bits 2-0 (0x00000007) contain parent bus number. Zero if no parent * bus, 1 = parent is AHB BUS 0 (i0), 2 = parent is AHB BUS 1 (i1).. * * Bridge Address * -------------- * Bits 10-5 (0x000007e0) contain the index of the Bridge's PnP * information on the parent. Since all bridges are found in the * PnP information they all have a PnP entry. Together with the * parent bus number the PnP entry can be found: * PnPEntry = (BRIDGE_ADDRESS + (iN & 0xfff00000)) | 0x000ff800 * where N is the parent bus minus one. * */ /* Function initializes the AHB Bridge I/O AREA storage. (Clears i0-i5) * * Arguments * none * * Results * none * * Clobbered * none */ init_ahb_bridges: mov %g0, %i0 mov %g0, %i1 mov %g0, %i2 mov %g0, %i3 mov %g0, %i4 retl mov %g0, %i5 /* Function returns AHB Bridge I/O AREA for specified bus. * * Arguments * - o0 = bus number * * Results * - o0 = I/O AREA * * Clobbered * none */ get_ahb_bridge: cmp %o0, 1 be,a L1 mov %i0, %o0 cmp %o0, 2 be,a L1 mov %i1, %o0 cmp %o0, 3 be,a L1 mov %i2, %o0 cmp %o0, 4 be,a L1 mov %i3, %o0 cmp %o0, 5 be,a L1 mov %i4, %o0 cmp %o0, 6 be,a L1 mov %i5, %o0 /* o0 > 6: only 6 buses supported */ mov %g0, %o0 L1: retl nop /* Function adds a AHB Bridge I/O AREA to the i0-i5 registers if * not already added. It stores the bus PnP start information. * * Arguments * - o0 = AHB Bridge I/O area * * Results * none * * Clobbered * o2, o3 */ insert_ahb_bridge: /* Check that bridge hasn't already been added */ andn %o0, 0x7ff, %o2 andn %i0, 0x7ff, %o3 cmp %o3, %o2 be L2 andn %i1, 0x7ff, %o3 cmp %o3, %o2 be L2 andn %i2, 0x7ff, %o3 cmp %o3, %o2 be L2 andn %i3, 0x7ff, %o3 cmp %o3, %o2 be L2 andn %i4, 0x7ff, %o3 cmp %o3, %o2 be L2 andn %i5, 0x7ff, %o3 cmp %o3, %o2 be L2 /* Insert into first free posistion */ cmp %i0, %g0 be,a L2 mov %o0, %i0 cmp %i1, %g0 be,a L2 mov %o0, %i1 cmp %i2, %g0 be,a L2 mov %o0, %i2 cmp %i3, %g0 be,a L2 mov %o0, %i3 cmp %i4, %g0 be,a L2 mov %o0, %i4 cmp %i5, %g0 be,a L2 mov %o0, %i5 L2: retl nop /* FUNCTION int _nomem_find_ahb_bus( * unsigned int bridge, * int vendor_device, * int index, * void **pconf, * int not_used, * int option * ) * * Scans the AHB Master or Slave area for a matching VENDOR:DEVICE, the * index is decremented when a matching device is found but index is * greater than zero. When index is zero and a matching DEVICE:VENDOR * is found the AHB configuration address and AHB I/O area is returned. * * i0-i7,l0,l1,l2,l3,l4,g2,o6 is not available for use. * o1,o5 Must be left untouched * * Results * - o0 Number of found devices (1 or 0) * - o2 is decremented for each matching VENDOR:DEVICE found, zero if found * - o3 Address of the AHB PnP configuration entry (Only valid if o0=1) * * Clobbered * - o3 (Clobbered when no device was found) * - o4 (Number of Devices left to search) * - o0 (Bus ID, PnP ID, Device) */ _nomem_find_ahb_bus: /* Get the number of Slaves/Masters. * Only AHB Bus 0 has 64 AHB Masters/Slaves the * other AHB buses has 16 slaves and 16 masters. */ add %g0, 16, %o4 /* Defaulting to 16 */ andcc %o0, 0x7, %g0 /* 3-bit bus id */ be,a .L_maxloops_detected add %g0, 64, %o4 /* AHB Bus 0 has 64 AHB Masters/Slaves */ .L_maxloops_detected: /* Get start address of AHB Slave or AHB Master area depending on what * we are searching for. */ andn %o0, 0x7ff, %o0 /* Remove Bus ID and 5-bit AHB/AHB * Bridge PnP Address to get I/O Area */ set AMBA_CONF_AREA, %o3 or %o3, %o0, %o3 /* Master area address */ cmp %o5, DEV_AHB_SLV be,a .L_conf_area_calculated or %o3, AMBA_AHB_SLAVE_CONF_AREA, %o3 /* Add 0x800 to get to slave area */ .L_conf_area_calculated: /* Iterate over all AHB device and try to find matching DEVICE:VENDOR * o1 - VENDOR|DEVICE * o2 - Index * o3 - Current AHB Device Configuration address * o5 - Type (leave untouched) * * o4 - Number of AHB device left to process * o0 - tmp */ .L_process_one_conf: ld [%o3], %o0 andn %o0, 0xfff, %o0 cmp %o0, 0 /* No device if zero */ beq .L_next_conf cmp %o1, 0 /* If VENDOR:DEVICE==0, consider all matching */ beq .L_process_ahb_dev_found cmp %o0, %o1 /* Does VENDOR and DEVICE Match? */ bne .L_next_conf nop .L_process_ahb_dev_found: /* Found a Matching VENDOR:DEVICE, index must also match */ cmp %o2, %g0 bne .L_next_conf dec %o2 /* Index matches also, return happy with o3 set to AHB Conf Address */ mov %g0, %o2 retl add %g0, 1, %o0 .L_next_conf: subcc %o4, 1, %o4 /* One device has been processed, * Are there more devices to process? */ bne .L_process_one_conf add %o3, AMBA_AHB_CONF_LENGH, %o3 /* Next Configuration entry */ /* No Matching device found */ retl mov %g0, %o0 /* FUNCTION int _nomem_find_ahb( * int unused, * int vendor_device, * int index, * void **pconf, * int *ahb_bus_index, * int option, * ) * * Find a AHB Master or AHB Slave device, it puts the address of the AHB PnP * configuration in o3 (pconf), the I/O Area base address in o4 (pioarea). * * Calls _nomem_find_ahb_bus for every AHB bus. * * i0-i7, l0, l1, o6, g1, g4-g7 is not available for use. * * Arguments * - o0 Unused * * Results * - o0 Number of found devices (1 or 0) * - o2 Decremented Index (Zero if found) * - o3 Address of the AHB PnP configuration entry * - o4 AHB Bus index the device was found on (if o0=1) * - o5 Left untouched * * Clobbered * - o0 (AHB Bridge and used by _nomem_find_ahb_bus) * - o2 (index is decremented) * - l2 (Current AHB Bus index) * - g2 (return address) */ _nomem_find_ahb: mov %o7, %g2 /* Save return address */ /* Scan all AHB Buses found for the AHB Master/Slave matching VENDOR:DEVICE */ clr %l2 .L_search_next_ahb_bus: add %l2, 1, %l2 call get_ahb_bridge /* Get bus %l0 I/O Area */ mov %l2, %o0 cmp %o0, %g0 be .L_no_device_found /* If no more AHB bus is left to be scanned, proceed */ nop call _nomem_find_ahb_bus /* Scan AHB bus %o0 for VENDOR:DEVICE. Index in o3 is decremented */ nop cmp %o0, %g0 /* If VENDOR:DEVICE was not found scan next AHB Bus */ be .L_search_next_ahb_bus /* Do next bus is o0=0 (not found) */ nop /* The device was found, o0 is 1 */ mov %g2, %o7 /* Restore return address */ retl mov %l2, %o4 /* The AHB bus index the device was found on */ /* No device found matching */ .L_no_device_found: mov %g2, %o7 /* Restore return address */ retl mov %g0, %o0 /* FUNCTION int _nomem_find_apb_bus( * int apbmst, * int vendor_device, * int index, * void **pconf * ) * * Find a APB Slave device, it puts the address of the APB PnP configuration * in o3 (pconf). * * Calls _nomem_find_ahb_bus for every AHB bus searching for AHB/APB Bridges. * The AHB/APB bridges are AHB Slaves with ID GAISLER_APBMST. * * Results * - o0 Number of found devices (1 or 0) * - o2 Decremented Index * - o3 Address of the found APB device PnP configuration entry * * Clobbered * - o5 PnP VENDOR:DEVICE ID */ _nomem_find_apb_bus: set AMBA_CONF_AREA, %o3 or %o0, %o3, %o3 /* Calc start of APB device PnP info */ add %g0, 16, %o0 /* o0, number of APB Slaves left to scan */ .L_process_one_apb_conf: ld [%o3], %o5 andn %o5, 0xfff, %o5 cmp %o5, 0 /* No device if zero */ beq .L_process_apb_dev_not_found cmp %o1, 0 /* If VENDOR:DEVICE == -1, consider all matching */ beq .L_process_apb_dev_found cmp %o1, %o5 /* Found VENDOR:DEVICE */ bne .L_process_apb_dev_not_found nop .L_process_apb_dev_found: /* Found matching device, compare index */ cmp %o2, %g0 bne .L_process_apb_dev_not_found dec %o2 /* Matching index and VENDOR:DEVICE */ retl add %g0, 1, %o0 .L_process_apb_dev_not_found: subcc %o0, 1, %o0 bne .L_process_one_apb_conf add %o3, 8, %o3 retl mov %g0, %o0 /* FUNCTION int _nomem_find_apb( * int unused, * int vendor_device, * int index, * void **pconf, * int *ahb_bus_index * ) * * Find a APB Slave device, it puts the address of the APB PnP configuration * in o3 (pconf), the APB Master I/O Area base address in o4 (papbarea). * * Calls _nomem_find_ahb_bus for every AHB bus searching for AHB/APB Bridges. * The AHB/APB bridges are AHB Slaves with ID GAISLER_APBMST. * * i0-i7, l0, l1, o6 is not available for use. * * Arguments * - o0 Unused * * Results * - o0 Number of found devices (1 or 0) * - o2 Decremented Index if not found * - o3 Address of the APB PnP configuration entry * - o4 AHB Bus index of APB Bridge/APB Device * * Clobbered * - o0 (AHB Bridge) * - o2 (index is decremented) * - l2 (APB DEV Index [7..4] : APBMST AHB Index [3..0]) * - l3 (Current AHB Bus index) * - l4 (temporary storage for APB VENDOR:DEVICE) * - o5 (AHB Slave ID) * - o0 (clobbered by _nomem_find_ahb_bus) * - g2 (Return address) */ _nomem_find_apb: /* Scan all AHB Buses found for AHB/APB Bridges */ mov %o7, %g2 /* Save return address */ mov %o1, %l4 /* Save APB VENDOR:DEVICE */ sll %o2, 4, %l2 /* APB MST index = 0 */ add %g0, 1, %l3 /* AHB Bus index = 0 */ .L2_search_next_ahb_bus: call get_ahb_bridge /* Get bus %l3 I/O Area */ mov %l3, %o0 cmp %o0, %g0 be .L2_no_device_found /* If no more AHB bus is left to be scanned, proceed */ add %g0, DEV_AHB_SLV, %o5 /* Search for AHB Slave */ sethi %hi(AMBA_PNP_ID(VENDOR_GAISLER, GAISLER_APBMST)), %o1 call _nomem_find_ahb_bus /* Scan AHB bus %o0 for VENDOR:DEVICE. Index in o3 is decremented */ and %l2, 0xf, %o2 /* Set APBMST index */ cmp %o0, %g0 /* If no AHB/APB Bridge was not found, scan next AHB Bus */ be .L_no_apb_bridge_found /* Do next bus */ nop /* The AHB/APB Bridge was found. * Search for the requested APB Device on the APB bus using * find_apb_bus, it will decrement the index. */ ld [%o3 + AMBA_AHB_MBAR0_OFS], %o3 sll %o3, 16, %o0 and %o0, %o3, %o0 /* Address AND Address Mask */ sethi %hi(0xfff00000), %o3 and %o0, %o3, %o0 /* AHB/APB Bridge address */ srl %l2, 4, %o2 /* APB DEV Index */ call _nomem_find_apb_bus mov %l4, %o1 /* APB VENDOR:DEVICE */ cmp %o0, %g0 be .L_apb_dev_not_found mov %g2, %o7 /* Restore return address */ /* APB Device found * o0 1 * o2 Index is decremented to zero * o3 APB configuration address, * o4 APB Bridge Configuration address. */ mov %g0, %o2 retl mov %l3, %o4 .L_apb_dev_not_found: /* Update APB DEV Index by saving output from find_apb_bus * (index parameter) into bits [31..4] in L2. */ sll %o2, 4, %o2 and %l2, 0xf, %l2 or %o2, %l2, %l2 /* Try finding the next AHB/APB Bridge on the same AHB bus * to find more APB devices */ ba .L2_search_next_ahb_bus /* Find next AHB/APB bridge */ inc %l2 .L_no_apb_bridge_found: inc %l3 /* Next AHB Bus */ ba .L2_search_next_ahb_bus /* Process next AHB bus */ andn %l2, 0xf, %l2 /* Start at APB Bridge index 0 at every AHB Bus */ /* No device found matching */ .L2_no_device_found: mov %g2, %o7 /* Restore return address */ srl %l2, 4, %o2 /* APB DEV Index */ retl mov %g0, %o0 /* FUNCTION _nomem_amba_scan_gaisler_ahb2ahb_bridge(unsigned int bridge, int bus) * * Constraints: * - o1 may not be used * - o0, o2, o3 may be used. * * Arguments * - o0 PnP Address of Bridge AHB device * - o2 PnP ID of AHB device * * Results * - o0 Address of new bus PnP area or a 1 if AHB device is no bridge * * Clobbered * - o0, o2 * */ _nomem_amba_scan_gaisler_ahb2ahb_bridge: andn %o2, 0xfff, %o2 sethi %hi(AMBA_PNP_ID(VENDOR_GAISLER,GAISLER_AHB2AHB)), %o3 cmp %o2, %o3 beq .L_is_ahb2ahb_bridge nop retl add %g0, 1, %o0 .L_is_ahb2ahb_bridge: /* Found a GAISLER AHB2AHB bridge */ retl ld [%o0 + AMBA_AHB_CUSTOM1_OFS], %o0 /* Get address of bridge PnP area */ /* FUNCTION _nomem_amba_scan_gaisler_l2cache_bridge(unsigned int bridge, int bus) * * Constraints: * - o1 may not be used * - o0, o2, o3 may be used. * * Arguments * - o0 PnP Address of Bridge AHB device * - o2 PnP ID of AHB device * * Results * - o0 Address of new bus PnP area or a 1 if AHB device is no bridge * * Clobbered * - o0, o2 * */ _nomem_amba_scan_gaisler_l2cache_bridge: andn %o2, 0xfff, %o2 sethi %hi(AMBA_PNP_ID(VENDOR_GAISLER,GAISLER_L2CACHE)), %o3 cmp %o2, %o3 beq .L_is_l2cache_bridge nop retl add %g0, 1, %o0 .L_is_l2cache_bridge: /* Found a GAISLER l2cache bridge */ retl ld [%o0 + AMBA_AHB_CUSTOM1_OFS], %o0 /* Get address of bridge PnP area */ /* FUNCTION _nomem_amba_scan(unsigned int bridge, int bus) * * Constraints: * i0-i7, l0 is used by caller * o5-o7 may not be used. * * Arguments * - o0 Bridge Information: I/O AREA and parent bus * - o1 Bus * * Results * - o0 Number of AHB bridges found * * Clobbered * - o0 (Current AHB slave conf address) * - o2 (Used by insert_bridge) * - o3 (Used by insert_bridge) * - l1 (Number of AHB Slaves left to process) * - l2 (Current AHB slave conf address) * - g2 (Return address) */ _nomem_amba_scan: mov %o7, %g2 /* Save return address */ set 16, %l1 cmp %o1, 1 be,a .L2_maxloops_detected add %g0, 64, %l1 .L2_maxloops_detected: /* Clear 3-bit parent bus from bridge to get I/O AREA, then or * (AMBA_CONF_AREA | AMBA_AHB_SLAVE_CONF_AREA) to get first AHB slave * conf address. */ andn %o0, 0x7ff, %o0 set (AMBA_CONF_AREA | AMBA_AHB_SLAVE_CONF_AREA), %l2 or %o0, %l2, %l2 /* Scan AHB Slave area for AHB<->AHB bridges. For each AHB device * all "bridge drivers" are called, the driver function interface: * * Input: * - o0 PnP Address of Bridge AHB device * - o2 PnP ID of AHB device * Return values: * - o0 Address of new bus PnP area, returning a 1 in o2 means not found * * Constraints: * - o1 may not be used * - o0, o2, o3 may be used. * */ .L_scan_one_ahb_slave: ld [%l2], %o2 cmp %o2, %g0 beq .L_scan_next_ahb_slave nop /* Call the GAISLER AHB2AHB bridge driver */ call _nomem_amba_scan_gaisler_ahb2ahb_bridge mov %l2, %o0 cmp %o0, 1 bne .L_found_bridge ld [%l2], %o2 /* Call the GAISLER L2CACHE bridge driver */ call _nomem_amba_scan_gaisler_l2cache_bridge mov %l2, %o0 cmp %o0, 1 bne .L_found_bridge ld [%l2], %o2 /* Insert next bridge "driver" function here */ /* The PnP ID did not match a bridge - a new bus was not found ==> * step to next AHB device */ ba .L_scan_next_ahb_slave nop /* Add Found bus */ .L_found_bridge: and %l2, 0x7e0, %o2 or %o2, %o0, %o0 /* Add AHB/AHB Bridge PnP address */ call insert_ahb_bridge /* Insert Bridge into found buses storage */ or %o1, %o0, %o0 /* Add parent bus LSB 3-bits */ .L_scan_next_ahb_slave: /* More Slaves to process? */ subcc %l1, 1, %l1 bne .L_scan_one_ahb_slave add %l2, AMBA_AHB_CONF_LENGH, %l2 /* No more AHB devices to process */ mov %g2, %o7 /* Restore return address */ retl nop /* FUNCTION _nomem_ambapp_find_buses(unsigned int ioarea) * * Find AMBA AHB buses. * * Constraints: * i6-i7, l7 is used by caller * * Arguments * - o0 Bridge Information: I/O AREA and parent bus * * Results * - o0 Number of AHB bridges found * - i0-i5 initialized * * Clobbered * - o0 (Current AHB slave conf address) * - o2 (Used by insert_bridge) * - o3 (Used by insert_bridge) * - l0 (Current AHB Bus) * - l1 (Used by nomem_amba_scan) * - l2 (Used by nomem_amba_scan) * - l3 (Used by nomem_amba_scan) * - l4 (Used by nomem_amba_scan) * * - g1 (level 1 return address) * - g2 (Used by nomem_amba_scan) */ _nomem_ambapp_find_buses: mov %o7, %g1 /* Save return address */ /* Initialize AHB Bus storage */ call init_ahb_bridges nop /* Insert AHB Bus 0 */ call insert_ahb_bridge nop /* Argument already prepared by caller */ /* Scan AHB Bus 0 for AHB Bridges */ call _nomem_amba_scan add %g0, 1, %o1 /* Scan all AHB Buses found for more AHB Bridges */ add %g0, 2, %l0 .L100_search_next_ahb_bus: call get_ahb_bridge /* Get bus %l0 I/O Area */ mov %l0, %o0 cmp %o0, %g0 be .L100_return /* If no more AHB bus is left to be scanned, proceed */ nop call _nomem_amba_scan /* Scan bus %l0 for AHB Bridges. i0-i7,l0 is used */ mov %l0, %o1 /* I/O AREA untouched in o0 */ ba .L100_search_next_ahb_bus /* Do next bus */ add %l0, 1, %l0 .L100_return: mov %g1, %o7 retl nop /* FUNCTION _nomem_amba_init(unsigned int ioarea) * * Find all AHB buses * * Constraints: * i6, i7, o6, o7, l7, l6, g3, g4, g5, g6, g7 is used by caller * * Arguments * - o0 Bridge Information: I/O AREA and parent bus * * Results * - o0 Number of AHB bridges found * * Clobbered * - l0, l1, l2, l3, l4, g1, g2 (used by _nomem_ambapp_find_buses) * - o0, o1, o2, o3 (Used as arguments) * - o5 (return address) * - g1 (level 1 return address) * - g2 (level 2 return address) */ _nomem_amba_init: mov %o7, %o5 /* Save return address, o5 not used */ /* Scan for buses, it will init i0-i5 */ call _nomem_ambapp_find_buses nop mov %o5, %o7 retl nop /* Call tree and their return address register * *_nomem_amba_scan (g1) * -> init_ahb_bridges (o7) * -> insert_ahb_bridge (o7) * -> _nomem_amba_scan (g2) * -> insert_ahb_bridge (o7) * -> get_ahb_bridge (o7) * * * -> _nomem_find_apb (g2) * -> get_ahb_bridge (o7) * -> _nomem_find_ahb_bus (o7) * -> _nomem_find_apb_bus (o7) * -> _nomem_find_ahb (g2) * -> get_ahb_bridge (o7) * -> _nomem_find_ahb_bus (o7) * -> mem_handler.func() (o7) * */