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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/scsi/atari_dma_emul.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/scsi/atari_dma_emul.c')
-rw-r--r-- | drivers/scsi/atari_dma_emul.c | 466 |
1 files changed, 466 insertions, 0 deletions
diff --git a/drivers/scsi/atari_dma_emul.c b/drivers/scsi/atari_dma_emul.c new file mode 100644 index 000000000000..7026045527fd --- /dev/null +++ b/drivers/scsi/atari_dma_emul.c @@ -0,0 +1,466 @@ +/* + * atari_dma_emul.c -- TT SCSI DMA emulator for the Hades. + * + * Copyright 1997 Wout Klaren <W.Klaren@inter.nl.net> + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of this archive + * for more details. + * + * This code was written using the Hades TOS source code as a + * reference. This source code can be found on the home page + * of Medusa Computer Systems. + * + * Version 0.1, 1997-09-24. + * + * This code should be considered experimental. It has only been + * tested on a Hades with a 68060. It might not work on a Hades + * with a 68040. Make backups of your hard drives before using + * this code. + */ + +#include <asm/uaccess.h> + +#define hades_dma_ctrl (*(unsigned char *) 0xffff8717) +#define hades_psdm_reg (*(unsigned char *) 0xffff8741) + +#define TRANSFER_SIZE 16 + +struct m68040_frame { + unsigned long effaddr; /* effective address */ + unsigned short ssw; /* special status word */ + unsigned short wb3s; /* write back 3 status */ + unsigned short wb2s; /* write back 2 status */ + unsigned short wb1s; /* write back 1 status */ + unsigned long faddr; /* fault address */ + unsigned long wb3a; /* write back 3 address */ + unsigned long wb3d; /* write back 3 data */ + unsigned long wb2a; /* write back 2 address */ + unsigned long wb2d; /* write back 2 data */ + unsigned long wb1a; /* write back 1 address */ + unsigned long wb1dpd0; /* write back 1 data/push data 0*/ + unsigned long pd1; /* push data 1*/ + unsigned long pd2; /* push data 2*/ + unsigned long pd3; /* push data 3*/ +}; + +static void writeback (unsigned short wbs, unsigned long wba, + unsigned long wbd, void *old_buserr) +{ + mm_segment_t fs = get_fs(); + static void *save_buserr; + + __asm__ __volatile__ ("movec.l %%vbr,%%a0\n\t" + "move.l %0,8(%%a0)\n\t" + : + : "r" (&&bus_error) + : "a0" ); + + save_buserr = old_buserr; + + set_fs (MAKE_MM_SEG(wbs & WBTM_040)); + + switch (wbs & WBSIZ_040) { + case BA_SIZE_BYTE: + put_user (wbd & 0xff, (char *)wba); + break; + case BA_SIZE_WORD: + put_user (wbd & 0xffff, (short *)wba); + break; + case BA_SIZE_LONG: + put_user (wbd, (int *)wba); + break; + } + + set_fs (fs); + return; + +bus_error: + __asm__ __volatile__ ("cmp.l %0,2(%%sp)\n\t" + "bcs.s .jump_old\n\t" + "cmp.l %1,2(%%sp)\n\t" + "bls.s .restore_old\n" + ".jump_old:\n\t" + "move.l %2,-(%%sp)\n\t" + "rts\n" + ".restore_old:\n\t" + "move.l %%a0,-(%%sp)\n\t" + "movec.l %%vbr,%%a0\n\t" + "move.l %2,8(%%a0)\n\t" + "move.l (%%sp)+,%%a0\n\t" + "rte\n\t" + : + : "i" (writeback), "i" (&&bus_error), + "m" (save_buserr) ); +} + +/* + * static inline void set_restdata_reg(unsigned char *cur_addr) + * + * Set the rest data register if necessary. + */ + +static inline void set_restdata_reg(unsigned char *cur_addr) +{ + if (((long) cur_addr & ~3) != 0) + tt_scsi_dma.dma_restdata = + *((unsigned long *) ((long) cur_addr & ~3)); +} + +/* + * void hades_dma_emulator(int irq, void *dummy, struct pt_regs *fp) + * + * This code emulates TT SCSI DMA on the Hades. + * + * Note the following: + * + * 1. When there is no byte available to read from the SCSI bus, or + * when a byte cannot yet bet written to the SCSI bus, a bus + * error occurs when reading or writing the pseudo DMA data + * register (hades_psdm_reg). We have to catch this bus error + * and try again to read or write the byte. If after several tries + * we still get a bus error, the interrupt handler is left. When + * the byte can be read or written, the interrupt handler is + * called again. + * + * 2. The SCSI interrupt must be disabled in this interrupt handler. + * + * 3. If we set the EOP signal, the SCSI controller still expects one + * byte to be read or written. Therefore the last byte is transferred + * separately, after setting the EOP signal. + * + * 4. When this function is left, the address pointer (start_addr) is + * converted to a physical address. Because it points one byte + * further than the last transferred byte, it can point outside the + * current page. If virt_to_phys() is called with this address we + * might get an access error. Therefore virt_to_phys() is called with + * start_addr - 1 if the count has reached zero. The result is + * increased with one. + */ + +static irqreturn_t hades_dma_emulator(int irq, void *dummy, struct pt_regs *fp) +{ + unsigned long dma_base; + register unsigned long dma_cnt asm ("d3"); + static long save_buserr; + register unsigned long save_sp asm ("d4"); + register int tries asm ("d5"); + register unsigned char *start_addr asm ("a3"), *end_addr asm ("a4"); + register unsigned char *eff_addr; + register unsigned char *psdm_reg; + unsigned long rem; + + atari_disable_irq(IRQ_TT_MFP_SCSI); + + /* + * Read the dma address and count registers. + */ + + dma_base = SCSI_DMA_READ_P(dma_addr); + dma_cnt = SCSI_DMA_READ_P(dma_cnt); + + /* + * Check if DMA is still enabled. + */ + + if ((tt_scsi_dma.dma_ctrl & 2) == 0) + { + atari_enable_irq(IRQ_TT_MFP_SCSI); + return IRQ_HANDLED; + } + + if (dma_cnt == 0) + { + printk(KERN_NOTICE "DMA emulation: count is zero.\n"); + tt_scsi_dma.dma_ctrl &= 0xfd; /* DMA ready. */ + atari_enable_irq(IRQ_TT_MFP_SCSI); + return IRQ_HANDLED; + } + + /* + * Install new bus error routine. + */ + + __asm__ __volatile__ ("movec.l %%vbr,%%a0\n\t" + "move.l 8(%%a0),%0\n\t" + "move.l %1,8(%%a0)\n\t" + : "=&r" (save_buserr) + : "r" (&&scsi_bus_error) + : "a0" ); + + hades_dma_ctrl &= 0xfc; /* Bus error and EOP off. */ + + /* + * Save the stack pointer. + */ + + __asm__ __volatile__ ("move.l %%sp,%0\n\t" + : "=&r" (save_sp) ); + + tries = 100; /* Maximum number of bus errors. */ + start_addr = phys_to_virt(dma_base); + end_addr = start_addr + dma_cnt; + +scsi_loop: + dma_cnt--; + rem = dma_cnt & (TRANSFER_SIZE - 1); + dma_cnt &= ~(TRANSFER_SIZE - 1); + psdm_reg = &hades_psdm_reg; + + if (tt_scsi_dma.dma_ctrl & 1) /* Read or write? */ + { + /* + * SCSI write. Abort when count is zero. + */ + + switch (rem) + { + case 0: + while (dma_cnt > 0) + { + dma_cnt -= TRANSFER_SIZE; + + *psdm_reg = *start_addr++; + case 15: + *psdm_reg = *start_addr++; + case 14: + *psdm_reg = *start_addr++; + case 13: + *psdm_reg = *start_addr++; + case 12: + *psdm_reg = *start_addr++; + case 11: + *psdm_reg = *start_addr++; + case 10: + *psdm_reg = *start_addr++; + case 9: + *psdm_reg = *start_addr++; + case 8: + *psdm_reg = *start_addr++; + case 7: + *psdm_reg = *start_addr++; + case 6: + *psdm_reg = *start_addr++; + case 5: + *psdm_reg = *start_addr++; + case 4: + *psdm_reg = *start_addr++; + case 3: + *psdm_reg = *start_addr++; + case 2: + *psdm_reg = *start_addr++; + case 1: + *psdm_reg = *start_addr++; + } + } + + hades_dma_ctrl |= 1; /* Set EOP. */ + udelay(10); + *psdm_reg = *start_addr++; /* Dummy byte. */ + tt_scsi_dma.dma_ctrl &= 0xfd; /* DMA ready. */ + } + else + { + /* + * SCSI read. Abort when count is zero. + */ + + switch (rem) + { + case 0: + while (dma_cnt > 0) + { + dma_cnt -= TRANSFER_SIZE; + + *start_addr++ = *psdm_reg; + case 15: + *start_addr++ = *psdm_reg; + case 14: + *start_addr++ = *psdm_reg; + case 13: + *start_addr++ = *psdm_reg; + case 12: + *start_addr++ = *psdm_reg; + case 11: + *start_addr++ = *psdm_reg; + case 10: + *start_addr++ = *psdm_reg; + case 9: + *start_addr++ = *psdm_reg; + case 8: + *start_addr++ = *psdm_reg; + case 7: + *start_addr++ = *psdm_reg; + case 6: + *start_addr++ = *psdm_reg; + case 5: + *start_addr++ = *psdm_reg; + case 4: + *start_addr++ = *psdm_reg; + case 3: + *start_addr++ = *psdm_reg; + case 2: + *start_addr++ = *psdm_reg; + case 1: + *start_addr++ = *psdm_reg; + } + } + + hades_dma_ctrl |= 1; /* Set EOP. */ + udelay(10); + *start_addr++ = *psdm_reg; + tt_scsi_dma.dma_ctrl &= 0xfd; /* DMA ready. */ + + set_restdata_reg(start_addr); + } + + if (start_addr != end_addr) + printk(KERN_CRIT "DMA emulation: FATAL: Count is not zero at end of transfer.\n"); + + dma_cnt = end_addr - start_addr; + +scsi_end: + dma_base = (dma_cnt == 0) ? virt_to_phys(start_addr - 1) + 1 : + virt_to_phys(start_addr); + + SCSI_DMA_WRITE_P(dma_addr, dma_base); + SCSI_DMA_WRITE_P(dma_cnt, dma_cnt); + + /* + * Restore old bus error routine. + */ + + __asm__ __volatile__ ("movec.l %%vbr,%%a0\n\t" + "move.l %0,8(%%a0)\n\t" + : + : "r" (save_buserr) + : "a0" ); + + atari_enable_irq(IRQ_TT_MFP_SCSI); + + return IRQ_HANDLED; + +scsi_bus_error: + /* + * First check if the bus error is caused by our code. + * If not, call the original handler. + */ + + __asm__ __volatile__ ("cmp.l %0,2(%%sp)\n\t" + "bcs.s .old_vector\n\t" + "cmp.l %1,2(%%sp)\n\t" + "bls.s .scsi_buserr\n" + ".old_vector:\n\t" + "move.l %2,-(%%sp)\n\t" + "rts\n" + ".scsi_buserr:\n\t" + : + : "i" (&&scsi_loop), "i" (&&scsi_end), + "m" (save_buserr) ); + + if (CPU_IS_060) + { + /* + * Get effective address and restore the stack. + */ + + __asm__ __volatile__ ("move.l 8(%%sp),%0\n\t" + "move.l %1,%%sp\n\t" + : "=a&" (eff_addr) + : "r" (save_sp) ); + } + else + { + register struct m68040_frame *frame; + + __asm__ __volatile__ ("lea 8(%%sp),%0\n\t" + : "=a&" (frame) ); + + if (tt_scsi_dma.dma_ctrl & 1) + { + /* + * Bus error while writing. + */ + + if (frame->wb3s & WBV_040) + { + if (frame->wb3a == (long) &hades_psdm_reg) + start_addr--; + else + writeback(frame->wb3s, frame->wb3a, + frame->wb3d, &&scsi_bus_error); + } + + if (frame->wb2s & WBV_040) + { + if (frame->wb2a == (long) &hades_psdm_reg) + start_addr--; + else + writeback(frame->wb2s, frame->wb2a, + frame->wb2d, &&scsi_bus_error); + } + + if (frame->wb1s & WBV_040) + { + if (frame->wb1a == (long) &hades_psdm_reg) + start_addr--; + } + } + else + { + /* + * Bus error while reading. + */ + + if (frame->wb3s & WBV_040) + writeback(frame->wb3s, frame->wb3a, + frame->wb3d, &&scsi_bus_error); + } + + eff_addr = (unsigned char *) frame->faddr; + + __asm__ __volatile__ ("move.l %0,%%sp\n\t" + : + : "r" (save_sp) ); + } + + dma_cnt = end_addr - start_addr; + + if (eff_addr == &hades_psdm_reg) + { + /* + * Bus error occurred while reading the pseudo + * DMA register. Time out. + */ + + tries--; + + if (tries <= 0) + { + if ((tt_scsi_dma.dma_ctrl & 1) == 0) /* Read or write? */ + set_restdata_reg(start_addr); + + if (dma_cnt <= 1) + printk(KERN_CRIT "DMA emulation: Fatal " + "error while %s the last byte.\n", + (tt_scsi_dma.dma_ctrl & 1) + ? "writing" : "reading"); + + goto scsi_end; + } + else + goto scsi_loop; + } + else + { + /* + * Bus error during pseudo DMA transfer. + * Terminate the DMA transfer. + */ + + hades_dma_ctrl |= 3; /* Set EOP and bus error. */ + if ((tt_scsi_dma.dma_ctrl & 1) == 0) /* Read or write? */ + set_restdata_reg(start_addr); + goto scsi_end; + } +} |