/*
* NCR 5380 generic driver routines. These should make it *trivial*
* to implement 5380 SCSI drivers under Linux with a non-trantor
* architecture.
*
* Note that these routines also work with NR53c400 family chips.
*
* Copyright 1993, Drew Eckhardt
* Visionary Computing
* (Unix and Linux consulting and custom programming)
* drew@colorado.edu
* +1 (303) 666-5836
*
* DISTRIBUTION RELEASE 6.
*
* For more information, please consult
*
* NCR 5380 Family
* SCSI Protocol Controller
* Databook
*
* NCR Microelectronics
* 1635 Aeroplaza Drive
* Colorado Springs, CO 80916
* 1+ (719) 578-3400
* 1+ (800) 334-5454
*/
/*
* ++roman: To port the 5380 driver to the Atari, I had to do some changes in
* this file, too:
*
* - Some of the debug statements were incorrect (undefined variables and the
* like). I fixed that.
*
* - In information_transfer(), I think a #ifdef was wrong. Looking at the
* possible DMA transfer size should also happen for REAL_DMA. I added this
* in the #if statement.
*
* - When using real DMA, information_transfer() should return in a DATAOUT
* phase after starting the DMA. It has nothing more to do.
*
* - The interrupt service routine should run main after end of DMA, too (not
* only after RESELECTION interrupts). Additionally, it should _not_ test
* for more interrupts after running main, since a DMA process may have
* been started and interrupts are turned on now. The new int could happen
* inside the execution of NCR5380_intr(), leading to recursive
* calls.
*
* - I've added a function merge_contiguous_buffers() that tries to
* merge scatter-gather buffers that are located at contiguous
* physical addresses and can be processed with the same DMA setup.
* Since most scatter-gather operations work on a page (4K) of
* 4 buffers (1K), in more than 90% of all cases three interrupts and
* DMA setup actions are saved.
*
* - I've deleted all the stuff for AUTOPROBE_IRQ, REAL_DMA_POLL, PSEUDO_DMA
* and USLEEP, because these were messing up readability and will never be
* needed for Atari SCSI.
*
* - I've revised the NCR5380_main() calling scheme (relax the 'main_running'
* stuff), and 'main' is executed in a bottom half if awoken by an
* interrupt.
*
* - The code was quite cluttered up by "#if (NDEBUG & NDEBUG_*) printk..."
* constructs. In my eyes, this made the source rather unreadable, so I
* finally replaced that by the *_PRINTK() macros.
*
*/
/*
* Further development / testing that should be done :
* 1. Test linked command handling code after Eric is ready with
* the high level code.
*/
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_transport_spi.h>
#if (NDEBUG & NDEBUG_LISTS)
#define LIST(x, y) \
do { \
printk("LINE:%d Adding %p to %p\n", \
__LINE__, (void*)(x), (void*)(y)); \
if ((x) == (y)) \
udelay(5); \
} while (0)
#define REMOVE(w, x, y, z) \
do { \
printk("LINE:%d Removing: %p->%p %p->%p \n", \
__LINE__, (void*)(w), (void*)(x), \
(void*)(y), (void*)(z)); \
if ((x) == (y)) \
udelay(5); \
} while (0)
#else
#define LIST(x,y)
#define REMOVE(w,x,y,z)
#endif
#ifndef notyet
#undef LINKED
#endif
/*
* Design
* Issues :
*
* The other Linux SCSI drivers were written when Linux was Intel PC-only,
* and specifically for each board rather than each chip. This makes their
* adaptation to platforms like the Mac (Some of which use NCR5380's)
* more difficult than it has to be.
*
* Also, many of the SCSI drivers were written before the command queuing
* routines were implemented, meaning their implementations of queued
* commands were hacked on rather than designed in from the start.
*
* When I designed the Linux SCSI drivers I figured that
* while having two different SCSI boards in a system might be useful
* for debugging things, two of the same type wouldn't be used.
* Well, I was wrong and a number of users have mailed me about running
* multiple high-performance SCSI boards in a server.
*
* Finally, when I get questions from users, I have no idea what
* revision of my driver they are running.
*
* This driver attempts to address these problems :
* This is a generic 5380 driver. To use it on a different platform,
* one simply writes appropriate system specific macros (ie, data
* transfer - some PC's will use the I/O bus, 68K's must use
* memory mapped) and drops this file in their 'C' wrapper.
*
* As far as command queueing, two queues are maintained for
* each 5380 in the system - commands that haven't been issued yet,
* and commands that are currently executing. This means that an
* unlimited number of commands may be queued, letting
* more commands propagate from the higher driver levels giving higher
* throughput. Note that both I_T_L and I_T_L_Q nexuses are supported,
* allowing multiple commands to propagate all the way to a SCSI-II device
* while a command is already executing.
*
* To solve the multiple-boards-in-the-same-system problem,
* there is a separate instance structure for each instance
* of a 5380 in the system. So, multiple NCR5380 drivers will
* be able to coexist with appropriate changes to the high level
* SCSI code.
*
* A NCR5380_PUBLIC_REVISION macro is provided, with the release
* number (updated for each public release) printed by the
* NCR5380_print_options command, which should be called from the
* wrapper detect function, so that I know what release of the driver
* users are using.
*
* Issues specific to the NCR5380 :
*
* When used in a PIO or pseudo-dma mode, the NCR5380 is a braindead
* piece of hardware that requires you to sit in a loop polling for
* the REQ signal as long as you are connected. Some devices are
* brain dead (ie, many TEXEL CD ROM drives) and won't disconnect
* while doing long seek operations.
*
* The workaround for this is to keep track of devices that have
* disconnected. If the device hasn't disconnected, for commands that
* should disconnect, we do something like
*
* while (!REQ is asserted) { sleep for N usecs; poll for M usecs }
*
* Some tweaking of N and M needs to be done. An algorithm based
* on "time to data" would give the best results as long as short time
* to datas (ie, on the same track) were considered, however these
* broken devices are the exception rather than the rule and I'd rather
* spend my time optimizing for the normal case.
*
* Architecture :
*
* At the heart of the design is a coroutine, NCR5380_main,
* which is started when not running by the interrupt handler,
* timer, and queue command function. It attempts to establish
* I_T_L or I_T_L_Q nexuses by removing the commands from the
* issue queue and calling NCR5380_select() if a nexus
* is not established.
*
* Once a nexus is established, the NCR5380_information_transfer()
* phase goes through the various phases as instructed by the target.
* if the target goes into MSG IN and sends a DISCONNECT message,
* the command structure is placed into the per instance disconnected
* queue, and NCR5380_main tries to find more work. If USLEEP
* was defined, and the target is idle for too long, the system
* will try to sleep.
*
* If a command has disconnected, eventually an interrupt will trigger,
* calling NCR5380_intr() which will in turn call NCR5380_reselect
* to reestablish a nexus. This will run main if necessary.
*
* On command termination, the done function will be called as
* appropriate.
*
* SCSI pointers are maintained in the SCp field of SCSI command
* structures, being initialized after the command is connected
* in NCR5380_select, and set as appropriate in NCR5380_information_transfer.
* Note that in violation of the standard, an implicit SAVE POINTERS operation
* is done, since some BROKEN disks fail to issue an explicit SAVE POINTERS.
*/
/*
* Using this file :
* This file a skeleton Linux SCSI driver for the NCR 5380 series
* of chips. To use it, you write an architecture specific functions
* and macros and include this file in your driver.
*
* These macros control options :
* AUTOSENSE - if defined, REQUEST SENSE will be performed automatically
* for commands that return with a CHECK CONDITION status.
*
* LINKED - if defined, linked commands are supported.
*
* REAL_DMA - if defined, REAL DMA is used during the data transfer phases.
*
* SUPPORT_TAGS - if defined, SCSI-2 tagged queuing is used where possible
*
* These macros MUST be defined :
*
* NCR5380_read(register) - read from the specified register
*
* NCR5380_write(register, value) - write to the specific register
*
* Either real DMA *or* pseudo DMA may be implemented
* REAL functions :
* NCR5380_REAL_DMA should be defined if real DMA is to be used.
* Note that the DMA setup functions should return the number of bytes
* that they were able to program the controller for.
*
* Also note that generic i386/PC versions of these macros are
* available as NCR5380_i386_dma_write_setup,
* NCR5380_i386_dma_read_setup, and NCR5380_i386_dma_residual.
*
* NCR5380_dma_write_setup(instance, src, count) - initialize
* NCR5380_dma_read_setup(instance, dst, count) - initialize
* NCR5380_dma_residual(instance); - residual count
*
* PSEUDO functions :
* NCR5380_pwrite(instance, src, count)
* NCR5380_pread(instance, dst, count);
*
* If nothing specific to this implementation needs doing (ie, with external
* hardware), you must also define
*
* NCR5380_queue_command
* NCR5380_reset
* NCR5380_abort
* NCR5380_proc_info
*
* to be the global entry points into the specific driver, ie
* #define NCR5380_queue_command t128_queue_command.
*
* If this is not done, the routines will be defined as static functions
* with the NCR5380* names and the user must provide a globally
* accessible wrapper function.
*
* The generic driver is initialized by calling NCR5380_init(instance),
* after setting the appropriate host specific fields and ID. If the
* driver wishes to autoprobe for an IRQ line, the NCR5380_probe_irq(instance,
* possible) function may be used. Before the specific driver initialization
* code finishes, NCR5380_print_options should be called.
*/
static struct Scsi_Host *first_instance = NULL;
static struct scsi_host_template *the_template = NULL;
/* Macros ease life... :-) */
#define SETUP_HOSTDATA(in) \
struct NCR5380_hostdata *hostdata = \
(struct NCR5380_hostdata *)(in)->hostdata
#define HOSTDATA(in) ((struct NCR5380_hostdata *)(in)->hostdata)
#define NEXT(cmd) ((Scsi_Cmnd *)(cmd)->host_scribble)
#define SET_NEXT(cmd,next) ((cmd)->host_scribble = (void *)(next))
#define NEXTADDR(cmd) ((Scsi_Cmnd **)&(cmd)->host_scribble)
#define HOSTNO instance->host_no
#define H_NO(cmd) (cmd)->device->host->host_no
#ifdef SUPPORT_TAGS
/*
* Functions for handling tagged queuing
* =====================================
*
* ++roman (01/96): Now I've implemented SCSI-2 tagged queuing. Some notes:
*
* Using consecutive numbers for the tags is no good idea in my eyes. There
* could be wrong re-usings if the counter (8 bit!) wraps and some early
* command has been preempted for a long time. My solution: a bitfield for
* remembering used tags.
*
* There's also the problem that each target has a certain queue size, but we
* cannot know it in advance :-( We just see a QUEUE_FULL status being
* returned. So, in this case, the driver internal queue size assumption is
* reduced to the number of active tags if QUEUE_FULL is returned by the
* target. The command is returned to the mid-level, but with status changed
* to BUSY, since --as I've seen-- the mid-level can't handle QUEUE_FULL
* correctly.
*
* We're also not allowed running tagged commands as long as an untagged
* command is active. And REQUEST SENSE commands after a contingent allegiance
* condition _must_ be untagged. To keep track whether an untagged command has
* been issued, the host->busy array is still employed, as it is without
* support for tagged queuing.
*
* One could suspect that there are possible race conditions between
* is_lun_busy(), cmd_get_tag() and cmd_free_tag(). But I think this isn't the
* case: is_lun_busy() and cmd_get_tag() are both called from NCR5380_main(),
* which already guaranteed to be running at most once. It is also the only
* place where tags/LUNs are allocated. So no other allocation can slip
* between that pair, there could only happen a reselection, which can free a
* tag, but that doesn't hurt. Only the sequence in cmd_free_tag() becomes
* important: the tag bit must be cleared before 'nr_allocated' is decreased.
*/
/* -1 for TAG_NONE is not possible with unsigned char cmd->tag */
#undef TAG_NONE
#define TAG_NONE 0xff
typedef struct {
DECLARE_BITMAP(allocated, MAX_TAGS);
int nr_allocated;
int queue_size;
} TAG_ALLOC;
static TAG_ALLOC TagAlloc[8][8]; /* 8 targets and 8 LUNs */
static void __init init_tags(void)
{
int target, lun;
TAG_ALLOC *ta;
if (!setup_use_tagged_queuing)
return;
for (target = 0; target < 8; ++target) {
for (lun = 0; lun < 8; ++lun) {
ta = &TagAlloc[target][lun];
bitmap_zero(ta->allocated, MAX_TAGS);
ta->nr_allocated = 0;
/* At the beginning, assume the maximum queue size we could
* support (MAX_TAGS). This value will be decreased if the target
* returns QUEUE_FULL status.
*/
ta->queue_size = MAX_TAGS;
}
}
}
/* Check if we can issue a command to this LUN: First see if the LUN is marked
* busy by an untagged command. If the command should use tagged queuing, also
* check that there is a free tag and the target's queue won't overflow. This
* function should be called with interrupts disabled to avoid race
* conditions.
*/
static int is_lun_busy(Scsi_Cmnd *cmd, int should_be_tagged)
{
SETUP_HOSTDATA(cmd->device->host);
if (hostdata->busy[cmd->device->id] & (1 << cmd->device->lun))
return 1;
if (!should_be_tagged ||
!setup_use_tagged_queuing || !cmd->device->tagged_supported)
return 0;
if (TagAlloc[cmd->device->id][cmd->device->lun].nr_allocated >=
TagAlloc[cmd->device->id][cmd->device->lun].queue_size) {
TAG_PRINTK("scsi%d: target %d lun %d: no free tags\n",
H_NO(cmd), cmd->device->id, cmd->device->lun);
return 1;
}
return 0;
}
/* Allocate a tag for a command (there are no checks anymore, check_lun_busy()
* must be called before!), or reserve the LUN in 'busy' if the command is
* untagged.
*/
static void cmd_get_tag(Scsi_Cmnd *cmd, int should_be_tagged)
{
SETUP_HOSTDATA(cmd->device->host);
/* If we or the target don't support tagged queuing, allocate the LUN for
* an untagged command.
*/
if (!should_be_tagged ||
!setup_use_tagged_queuing || !cmd->device->tagged_supported) {
cmd->tag = TAG_NONE;
hostdata->busy[cmd->device->id] |= (1 << cmd->device->lun);
TAG_PRINTK("scsi%d: target %d lun %d now allocated by untagged "
"command\n", H_NO(cmd), cmd->device->id, cmd->device->lun);
} else {
TAG_ALLOC *ta = &TagAlloc[cmd->device->id][cmd->device->lun];
cmd->tag = find_first_zero_bit(ta->allocated, MAX_TAGS);
set_bit(cmd->tag, ta->allocated);
ta->nr_allocated++;
TAG_PRINTK("scsi%d: using tag %d for target %d lun %d "
"(now %d tags in use)\n",
H_NO(cmd), cmd->tag, cmd->device->id,
cmd->device->lun, ta->nr_allocated);
}
}
/* Mark the tag of command 'cmd' as free, or in case of an untagged command,
* unlock the LUN.
*/
static void cmd_free_tag(Scsi_Cmnd *cmd)
{
SETUP_HOSTDATA(cmd->device->host);
if (cmd->tag == TAG_NONE) {
hostdata->busy[cmd->device->id] &= ~(1 << cmd->device->lun);
TAG_PRINTK("scsi%d: target %d lun %d untagged cmd finished\n",
H_NO(cmd), cmd->device->id, cmd->device->lun);
} else if (cmd->tag >= MAX_TAGS) {
printk(KERN_NOTICE "scsi%d: trying to free bad tag %d!\n",
H_NO(cmd), cmd->tag);
} else {
TAG_ALLOC *ta = &TagAlloc[cmd->device->id][cmd->device->lun];
clear_bit(cmd->tag, ta->allocated);
ta->nr_allocated--;
TAG_PRINTK("scsi%d: freed tag %d for target %d lun %d\n",
H_NO(cmd), cmd->tag, cmd->device->id, cmd->device->lun);
}
}
static void free_all_tags(void)
{
int target, lun;
TAG_ALLOC *ta;
if (!setup_use_tagged_queuing)
return;
for (target = 0; target < 8; ++target) {
for (lun = 0; lun < 8; ++lun) {
ta = &TagAlloc[target][lun];
bitmap_zero(ta->allocated, MAX_TAGS);
ta->nr_allocated = 0;
}
}
}
#endif /* SUPPORT_TAGS */
/*
* Function: void merge_contiguous_buffers( Scsi_Cmnd *cmd )
*
* Purpose: Try to merge several scatter-gather requests into one DMA
* transfer. This is possible if the scatter buffers lie on
* physical contiguous addresses.
*
* Parameters: Scsi_Cmnd *cmd
* The command to work on. The first scatter buffer's data are
* assumed to be already transfered into ptr/this_residual.
*/
static void merge_contiguous_buffers(Scsi_Cmnd *cmd)
{
unsigned long endaddr;
#if (NDEBUG & NDEBUG_MERGING)
unsigned long oldlen = cmd->SCp.this_residual;
int cnt = 1;
#endif
for (endaddr = virt_to_phys(cmd->SCp.ptr + cmd->SCp.this_residual - 1) + 1;
cmd->SCp.buffers_residual &&
virt_to_phys(sg_virt(&cmd->SCp.buffer[1])) == endaddr;) {
MER_PRINTK("VTOP(%p) == %08lx -> merging\n",
page_address(sg_page(&cmd->SCp.buffer[1])), endaddr);
#if (NDEBUG & NDEBUG_MERGING)
++cnt;
#endif
++cmd->SCp.buffer;
--cmd->SCp.buffers_residual;
cmd->SCp.this_residual += cmd->SCp.buffer->length;
endaddr += cmd->SCp.buffer->length;
}
#if (NDEBUG & NDEBUG_MERGING)
if (oldlen != cmd->SCp.this_residual)
MER_PRINTK("merged %d buffers from %p, new length %08x\n",
cnt, cmd->SCp.ptr, cmd->SCp.this_residual);
#endif
}
/*
* Function : void initialize_SCp(Scsi_Cmnd *cmd)
*
* Purpose : initialize the saved data pointers for cmd to point to the
* start of the buffer.
*
* Inputs : cmd - Scsi_Cmnd structure to have pointers reset.
*/
static inline void initialize_SCp(Scsi_Cmnd *cmd)
{
/*
* Initialize the Scsi Pointer field so that all of the commands in the
* various queues are valid.
*/
if (scsi_bufflen(cmd)) {
cmd->SCp.buffer = scsi_sglist(cmd);
cmd->SCp.buffers_residual = scsi_sg_count(cmd) - 1;
cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
cmd->SCp.this_residual = cmd->SCp.buffer->length;
/* ++roman: Try to merge some scatter-buffers if they are at
* contiguous physical addresses.
*/
merge_contiguous_buffers(cmd);
} else {
cmd->SCp.buffer = NULL;
cmd->SCp.buffers_residual = 0;
cmd->SCp.ptr = NULL;
cmd->SCp.this_residual = 0;
}
}
#include <linux/delay.h>
#if NDEBUG
static struct {
unsigned char mask;
const char *name;
} signals[] = {
{ SR_DBP, "PARITY"}, { SR_RST, "RST" }, { SR_BSY, "BSY" },
{ SR_REQ, "REQ" }, { SR_MSG, "MSG" }, { SR_CD, "CD" }, { SR_IO, "IO" },
{ SR_SEL, "SEL" }, {0, NULL}
}, basrs[] = {
{BASR_ATN, "ATN"}, {BASR_ACK, "ACK"}, {0, NULL}
}, icrs[] = {
{ICR_ASSERT_RST, "ASSERT RST"},{ICR_ASSERT_ACK, "ASSERT ACK"},
{ICR_ASSERT_BSY, "ASSERT BSY"}, {ICR_ASSERT_SEL, "ASSERT SEL"},
{ICR_ASSERT_ATN, "ASSERT ATN"}, {ICR_ASSERT_DATA, "ASSERT DATA"},
{0, NULL}
}, mrs[] = {
{MR_BLOCK_DMA_MODE, "MODE BLOCK DMA"}, {MR_TARGET, "MODE TARGET"},
{MR_ENABLE_PAR_CHECK, "MODE PARITY CHECK"}, {MR_ENABLE_PAR_INTR,
"MODE PARITY INTR"}, {MR_ENABLE_EOP_INTR,"MODE EOP INTR"},
{MR_MONITOR_BSY, "MODE MONITOR BSY"},
{MR_DMA_MODE, "MODE DMA"}, {MR_ARBITRATE, "MODE ARBITRATION"},
{0, NULL}
};
/*
* Function : void NCR5380_print(struct Scsi_Host *instance)
*
* Purpose : print the SCSI bus signals for debugging purposes
*
* Input : instance - which NCR5380
*/
static void NCR5380_print(struct Scsi_Host *instance)
{
unsigned char status, data, basr, mr, icr, i;