diff options
Diffstat (limited to 'arch/ppc/boot/simple/qspan_pci.c')
| -rw-r--r-- | arch/ppc/boot/simple/qspan_pci.c | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/arch/ppc/boot/simple/qspan_pci.c b/arch/ppc/boot/simple/qspan_pci.c new file mode 100644 index 0000000..d2966d0 --- /dev/null +++ b/arch/ppc/boot/simple/qspan_pci.c @@ -0,0 +1,269 @@ +/* + * LinuxPPC arch/ppc/kernel/qspan_pci.c Dan Malek (dmalek@jlc.net) + * + * QSpan Motorola bus to PCI bridge. The config address register + * is located 0x500 from the base of the bridge control/status registers. + * The data register is located at 0x504. + * This is a two step operation. First, the address register is written, + * then the data register is read/written as required. + * I don't know what to do about interrupts (yet). + */ + +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/pci.h> +#include <asm/mpc8xx.h> + +/* + * When reading the configuration space, if something does not respond + * the bus times out and we get a machine check interrupt. So, the + * good ol' exception tables come to mind to trap it and return some + * value. + * + * On an error we just return a -1, since that is what the caller wants + * returned if nothing is present. I copied this from __get_user_asm, + * with the only difference of returning -1 instead of EFAULT. + * There is an associated hack in the machine check trap code. + * + * The QSPAN is also a big endian device, that is it makes the PCI + * look big endian to us. This presents a problem for the Linux PCI + * functions, which assume little endian. For example, we see the + * first 32-bit word like this: + * ------------------------ + * | Device ID | Vendor ID | + * ------------------------ + * If we read/write as a double word, that's OK. But in our world, + * when read as a word, device ID is at location 0, not location 2 as + * the little endian PCI would believe. We have to switch bits in + * the PCI addresses given to us to get the data to/from the correct + * byte lanes. + * + * The QSPAN only supports 4 bits of "slot" in the dev_fn instead of 5. + * It always forces the MS bit to zero. Therefore, dev_fn values + * greater than 128 are returned as "no device found" errors. + * + * The QSPAN can only perform long word (32-bit) configuration cycles. + * The "offset" must have the two LS bits set to zero. Read operations + * require we read the entire word and then sort out what should be + * returned. Write operations other than long word require that we + * read the long word, update the proper word or byte, then write the + * entire long word back. + * + * PCI Bridge hack. We assume (correctly) that bus 0 is the primary + * PCI bus from the QSPAN. If we are called with a bus number other + * than zero, we create a Type 1 configuration access that a downstream + * PCI bridge will interpret. + */ + +#define __get_pci_config(x, addr, op) \ + __asm__ __volatile__( \ + "1: "op" %0,0(%1)\n" \ + " eieio\n" \ + "2:\n" \ + ".section .fixup,\"ax\"\n" \ + "3: li %0,-1\n" \ + " b 2b\n" \ + ".section __ex_table,\"a\"\n" \ + " .align 2\n" \ + " .long 1b,3b\n" \ + ".text" \ + : "=r"(x) : "r"(addr)) + +#define QS_CONFIG_ADDR ((volatile uint *)(PCI_CSR_ADDR + 0x500)) +#define QS_CONFIG_DATA ((volatile uint *)(PCI_CSR_ADDR + 0x504)) + +#define mk_config_addr(bus, dev, offset) \ + (((bus)<<16) | ((dev)<<8) | (offset & 0xfc)) + +#define mk_config_type1(bus, dev, offset) \ + mk_config_addr(bus, dev, offset) | 1; + +/* Initialize the QSpan device registers after power up. +*/ +void +qspan_init(void) +{ + uint *qptr; + + + + qptr = (uint *)PCI_CSR_ADDR; + + /* PCI Configuration/status. Upper bits written to clear + * pending interrupt or status. Lower bits enable QSPAN as + * PCI master, enable memory and I/O cycles, and enable PCI + * parity error checking. + * IMPORTANT: The last two bits of this word enable PCI + * master cycles into the QBus. The QSpan is broken and can't + * meet the timing specs of the PQ bus for this to work. Therefore, + * if you don't have external bus arbitration, you can't use + * this function. + */ +#ifdef EXTERNAL_PQ_ARB + qptr[1] = 0xf9000147; +#else + qptr[1] = 0xf9000144; +#endif + + /* PCI Misc configuration. Set PCI latency timer resolution + * of 8 cycles, set cache size to 4 x 32. + */ + qptr[3] = 0; + + /* Set up PCI Target address mapping. Enable, Posted writes, + * 2Gbyte space (processor memory controller determines actual size). + */ + qptr[64] = 0x8f000080; + + /* Map processor 0x80000000 to PCI 0x00000000. + * Processor address bit 1 determines I/O type access (0x80000000) + * or memory type access (0xc0000000). + */ + qptr[65] = 0x80000000; + + /* Enable error logging and clear any pending error status. + */ + qptr[80] = 0x90000000; + + qptr[512] = 0x000c0003; + + /* Set up Qbus slave image. + */ + qptr[960] = 0x01000000; + qptr[961] = 0x000000d1; + qptr[964] = 0x00000000; + qptr[965] = 0x000000d1; + +} + +/* Functions to support PCI bios-like features to read/write configuration + * space. If the function fails for any reason, a -1 (0xffffffff) value + * must be returned. + */ +#define DEVICE_NOT_FOUND (-1) +#define SUCCESSFUL 0 + +int qs_pci_read_config_byte(unsigned char bus, unsigned char dev_fn, + unsigned char offset, unsigned char *val) +{ + uint temp; + u_char *cp; + + if ((bus > 7) || (dev_fn > 127)) { + *val = 0xff; + return DEVICE_NOT_FOUND; + } + + if (bus == 0) + *QS_CONFIG_ADDR = mk_config_addr(bus, dev_fn, offset); + else + *QS_CONFIG_ADDR = mk_config_type1(bus, dev_fn, offset); + __get_pci_config(temp, QS_CONFIG_DATA, "lwz"); + + offset ^= 0x03; + cp = ((u_char *)&temp) + (offset & 0x03); + *val = *cp; + return SUCCESSFUL; +} + +int qs_pci_read_config_word(unsigned char bus, unsigned char dev_fn, + unsigned char offset, unsigned short *val) +{ + uint temp; + ushort *sp; + + if ((bus > 7) || (dev_fn > 127)) { + *val = 0xffff; + return DEVICE_NOT_FOUND; + } + + if (bus == 0) + *QS_CONFIG_ADDR = mk_config_addr(bus, dev_fn, offset); + else + *QS_CONFIG_ADDR = mk_config_type1(bus, dev_fn, offset); + __get_pci_config(temp, QS_CONFIG_DATA, "lwz"); + offset ^= 0x02; + + sp = ((ushort *)&temp) + ((offset >> 1) & 1); + *val = *sp; + return SUCCESSFUL; +} + +int qs_pci_read_config_dword(unsigned char bus, unsigned char dev_fn, + unsigned char offset, unsigned int *val) +{ + if ((bus > 7) || (dev_fn > 127)) { + *val = 0xffffffff; + return DEVICE_NOT_FOUND; + } + if (bus == 0) + *QS_CONFIG_ADDR = mk_config_addr(bus, dev_fn, offset); + else + *QS_CONFIG_ADDR = mk_config_type1(bus, dev_fn, offset); + __get_pci_config(*val, QS_CONFIG_DATA, "lwz"); + return SUCCESSFUL; +} + +int qs_pci_write_config_byte(unsigned char bus, unsigned char dev_fn, + unsigned char offset, unsigned char val) +{ + uint temp; + u_char *cp; + + if ((bus > 7) || (dev_fn > 127)) + return DEVICE_NOT_FOUND; + + qs_pci_read_config_dword(bus, dev_fn, offset, &temp); + + offset ^= 0x03; + cp = ((u_char *)&temp) + (offset & 0x03); + *cp = val; + + if (bus == 0) + *QS_CONFIG_ADDR = mk_config_addr(bus, dev_fn, offset); + else + *QS_CONFIG_ADDR = mk_config_type1(bus, dev_fn, offset); + *QS_CONFIG_DATA = temp; + + return SUCCESSFUL; +} + +int qs_pci_write_config_word(unsigned char bus, unsigned char dev_fn, + unsigned char offset, unsigned short val) +{ + uint temp; + ushort *sp; + + if ((bus > 7) || (dev_fn > 127)) + return DEVICE_NOT_FOUND; + + qs_pci_read_config_dword(bus, dev_fn, offset, &temp); + + offset ^= 0x02; + sp = ((ushort *)&temp) + ((offset >> 1) & 1); + *sp = val; + + if (bus == 0) + *QS_CONFIG_ADDR = mk_config_addr(bus, dev_fn, offset); + else + *QS_CONFIG_ADDR = mk_config_type1(bus, dev_fn, offset); + *QS_CONFIG_DATA = temp; + + return SUCCESSFUL; +} + +int qs_pci_write_config_dword(unsigned char bus, unsigned char dev_fn, + unsigned char offset, unsigned int val) +{ + if ((bus > 7) || (dev_fn > 127)) + return DEVICE_NOT_FOUND; + + if (bus == 0) + *QS_CONFIG_ADDR = mk_config_addr(bus, dev_fn, offset); + else + *QS_CONFIG_ADDR = mk_config_type1(bus, dev_fn, offset); + *(unsigned int *)QS_CONFIG_DATA = val; + + return SUCCESSFUL; +} + |