patch-2.3.20 linux/arch/ppc/kernel/qspan_pci.c

• Lines: 380
• Date: Thu Oct 7 10:17:08 1999
• Orig file: v2.3.19/linux/arch/ppc/kernel/qspan_pci.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.19/linux/arch/ppc/kernel/qspan_pci.c linux/arch/ppc/kernel/qspan_pci.c
@@ -0,0 +1,379 @@
+/*
+ * QSpan pci routines.
+ * Most 8xx boards use the QSpan 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).
+ *
+ * The RPX Classic implementation shares a chip select for normal
+ * PCI access and QSpan control register addresses.  The selection is
+ * further selected by a bit setting in a board control register.
+ * Although it should happen, we disable interrupts during this operation
+ * to make sure some driver doesn't accidently access the PCI while
+ * we have switched the chip select.
+ */
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/delay.h>
+#include <linux/string.h>
+#include <linux/init.h>
+
+#include <asm/io.h>
+#include <asm/mpc8xx.h>
+#include <asm/system.h>
+#include <asm/machdep.h>
+
+#include "pci.h"
+
+
+/*
+ * This blows......
+ * 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_qspan_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;
+
+int qspan_pcibios_read_config_byte(unsigned char bus, unsigned char dev_fn,
+				  unsigned char offset, unsigned char *val)
+{
+	uint	temp;
+	u_char	*cp;
+#ifdef CONFIG_RPXCLASSIC
+	unsigned long flags;
+#endif
+
+	if ((bus > 7) || (dev_fn > 127)) {
+		*val = 0xff;
+		return PCIBIOS_DEVICE_NOT_FOUND;
+	}
+
+#ifdef CONFIG_RPXCLASSIC
+	save_flags(flags);
+	cli();
+	*((uint *)RPX_CSR_ADDR) &= ~BCSR2_QSPACESEL;
+	eieio();
+#endif
+
+	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_qspan_pci_config(temp, QS_CONFIG_DATA, "lwz");
+
+#ifdef CONFIG_RPXCLASSIC
+	*((uint *)RPX_CSR_ADDR) |= BCSR2_QSPACESEL;
+	eieio();
+	restore_flags(flags);
+#endif
+
+	offset ^= 0x03;
+	cp = ((u_char *)&temp) + (offset & 0x03);
+	*val = *cp;
+	return PCIBIOS_SUCCESSFUL;
+}
+
+int qspan_pcibios_read_config_word(unsigned char bus, unsigned char dev_fn,
+				  unsigned char offset, unsigned short *val)
+{
+	uint	temp;
+	ushort	*sp;
+#ifdef CONFIG_RPXCLASSIC
+	unsigned long flags;
+#endif
+
+	if ((bus > 7) || (dev_fn > 127)) {
+		*val = 0xffff;
+		return PCIBIOS_DEVICE_NOT_FOUND;
+	}
+
+#ifdef CONFIG_RPXCLASSIC
+	save_flags(flags);
+	cli();
+	*((uint *)RPX_CSR_ADDR) &= ~BCSR2_QSPACESEL;
+	eieio();
+#endif
+
+	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_qspan_pci_config(temp, QS_CONFIG_DATA, "lwz");
+	offset ^= 0x02;
+
+#ifdef CONFIG_RPXCLASSIC
+	*((uint *)RPX_CSR_ADDR) |= BCSR2_QSPACESEL;
+	eieio();
+	restore_flags(flags);
+#endif
+
+	sp = ((ushort *)&temp) + ((offset >> 1) & 1);
+	*val = *sp;
+	return PCIBIOS_SUCCESSFUL;
+}
+
+int qspan_pcibios_read_config_dword(unsigned char bus, unsigned char dev_fn,
+				   unsigned char offset, unsigned int *val)
+{
+#ifdef CONFIG_RPXCLASSIC
+	unsigned long flags;
+#endif
+
+	if ((bus > 7) || (dev_fn > 127)) {
+		*val = 0xffffffff;
+		return PCIBIOS_DEVICE_NOT_FOUND;
+	}
+
+#ifdef CONFIG_RPXCLASSIC
+	save_flags(flags);
+	cli();
+	*((uint *)RPX_CSR_ADDR) &= ~BCSR2_QSPACESEL;
+	eieio();
+#endif
+
+	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_qspan_pci_config(*val, QS_CONFIG_DATA, "lwz");
+
+#ifdef CONFIG_RPXCLASSIC
+	*((uint *)RPX_CSR_ADDR) |= BCSR2_QSPACESEL;
+	eieio();
+	restore_flags(flags);
+#endif
+
+	return PCIBIOS_SUCCESSFUL;
+}
+
+int qspan_pcibios_write_config_byte(unsigned char bus, unsigned char dev_fn,
+				   unsigned char offset, unsigned char val)
+{
+	uint	temp;
+	u_char	*cp;
+#ifdef CONFIG_RPXCLASSIC
+	unsigned long flags;
+#endif
+
+	if ((bus > 7) || (dev_fn > 127))
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	qspan_pcibios_read_config_dword(bus, dev_fn, offset, &temp);
+
+	offset ^= 0x03;
+	cp = ((u_char *)&temp) + (offset & 0x03);
+	*cp = val;
+
+#ifdef CONFIG_RPXCLASSIC
+	save_flags(flags);
+	cli();
+	*((uint *)RPX_CSR_ADDR) &= ~BCSR2_QSPACESEL;
+	eieio();
+#endif
+
+	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;
+
+#ifdef CONFIG_RPXCLASSIC
+	*((uint *)RPX_CSR_ADDR) |= BCSR2_QSPACESEL;
+	eieio();
+	restore_flags(flags);
+#endif
+
+	return PCIBIOS_SUCCESSFUL;
+}
+
+int qspan_pcibios_write_config_word(unsigned char bus, unsigned char dev_fn,
+				   unsigned char offset, unsigned short val)
+{
+	uint	temp;
+	ushort	*sp;
+#ifdef CONFIG_RPXCLASSIC
+	unsigned long flags;
+#endif
+
+	if ((bus > 7) || (dev_fn > 127))
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	qspan_pcibios_read_config_dword(bus, dev_fn, offset, &temp);
+
+	offset ^= 0x02;
+	sp = ((ushort *)&temp) + ((offset >> 1) & 1);
+	*sp = val;
+
+#ifdef CONFIG_RPXCLASSIC
+	save_flags(flags);
+	cli();
+	*((uint *)RPX_CSR_ADDR) &= ~BCSR2_QSPACESEL;
+	eieio();
+#endif
+
+	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;
+
+#ifdef CONFIG_RPXCLASSIC
+	*((uint *)RPX_CSR_ADDR) |= BCSR2_QSPACESEL;
+	eieio();
+	restore_flags(flags);
+#endif
+
+	return PCIBIOS_SUCCESSFUL;
+}
+
+int qspan_pcibios_write_config_dword(unsigned char bus, unsigned char dev_fn,
+				    unsigned char offset, unsigned int val)
+{
+#ifdef CONFIG_RPXCLASSIC
+	unsigned long flags;
+#endif
+
+	if ((bus > 7) || (dev_fn > 127))
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+#ifdef CONFIG_RPXCLASSIC
+	save_flags(flags);
+	cli();
+	*((uint *)RPX_CSR_ADDR) &= ~BCSR2_QSPACESEL;
+	eieio();
+#endif
+
+	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;
+
+#ifdef CONFIG_RPXCLASSIC
+	*((uint *)RPX_CSR_ADDR) |= BCSR2_QSPACESEL;
+	eieio();
+	restore_flags(flags);
+#endif
+
+	return PCIBIOS_SUCCESSFUL;
+}
+
+int qspan_pcibios_find_device(unsigned short vendor, unsigned short dev_id,
+			     unsigned short index, unsigned char *bus_ptr,
+			     unsigned char *dev_fn_ptr)
+{
+    int num, devfn;
+    unsigned int x, vendev;
+
+    if (vendor == 0xffff)
+	return PCIBIOS_BAD_VENDOR_ID;
+    vendev = (dev_id << 16) + vendor;
+    num = 0;
+    for (devfn = 0;  devfn < 32;  devfn++) {
+	qspan_pcibios_read_config_dword(0, devfn<<3, PCI_VENDOR_ID, &x);
+	if (x == vendev) {
+	    if (index == num) {
+		*bus_ptr = 0;
+		*dev_fn_ptr = devfn<<3;
+		return PCIBIOS_SUCCESSFUL;
+	    }
+	    ++num;
+	}
+    }
+    return PCIBIOS_DEVICE_NOT_FOUND;
+}
+
+int qspan_pcibios_find_class(unsigned int class_code, unsigned short index,
+			    unsigned char *bus_ptr, unsigned char *dev_fn_ptr)
+{
+    int devnr, x, num;
+
+    num = 0;
+    for (devnr = 0;  devnr < 32;  devnr++) {
+	qspan_pcibios_read_config_dword(0, devnr<<3, PCI_CLASS_REVISION, &x);
+	if ((x>>8) == class_code) {
+	    if (index == num) {
+		*bus_ptr = 0;
+		*dev_fn_ptr = devnr<<3;
+		return PCIBIOS_SUCCESSFUL;
+	    }
+	    ++num;
+	}
+    }
+    return PCIBIOS_DEVICE_NOT_FOUND;
+}
+
+void __init
+m8xx_pcibios_fixup(void))
+{
+   /* Lots to do here, all board and configuration specific. */
+}
+
+void __init
+m8xx_setup_pci_ptrs(void))
+{
+	set_config_access_method(qspan);
+
+	ppc_md.pcibios_fixup = m8xx_pcibios_fixup;
+}
+