/*
* Copyright (c) 2008 Pavel Rimsky
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @addtogroup sparc64
* @{
*/
/**
* @file
* @brief SGCN driver.
*/
#include <arch/drivers/sgcn.h>
#include <genarch/ofw/ofw_tree.h>
#include <debug.h>
#include <func.h>
#include <print.h>
#include <mm/page.h>
#include <console/chardev.h>
#include <console/console.h>
#include <synch/spinlock.h>
/*
* Physical address at which the SBBC starts. This value has been obtained
* by inspecting (using Simics) memory accesses made by OBP. It is valid
* for the Simics-simulated Serengeti machine. The author of this code is
* not sure whether this value is valid generally.
*/
#define SBBC_START 0x63000000000
/* offset of SRAM within the SBBC memory */
#define SBBC_SRAM_OFFSET 0x900000
/* magic string contained at the beginning of SRAM */
#define SRAM_TOC_MAGIC "TOCSRAM"
/*
* Key into the SRAM table of contents which identifies the entry
* describing the OBP console buffer. It is worth mentioning
* that the OBP console buffer is not the only console buffer
* which can be used. It is, however, used because when the kernel
* is running, the OBP buffer is not used by OBP any more but OBP
* has already made neccessary arangements so that the output will
* be read from the OBP buffer and input will go to the OBP buffer.
* Therefore HelenOS needs to make no such arrangements any more.
*/
#define CONSOLE_KEY "OBPCONS"
/* magic string contained at the beginning of the console buffer */
#define SGCN_BUFFER_MAGIC "CON"
/*
* Returns a pointer to the object of a given type which is placed at the given
* offset from the SRAM beginning.
*/
#define SRAM(type, offset) ((type *) (sram_begin + (offset)))
/* Returns a pointer to the SRAM table of contents. */
#define SRAM_TOC (SRAM(iosram_toc_t, 0))
/*
* Returns a pointer to the object of a given type which is placed at the given
* offset from the console buffer beginning.
*/
#define SGCN_BUFFER(type, offset) \
((type *) (sgcn_buffer_begin + (offset)))
/* Returns a pointer to the console buffer header. */
#define SGCN_BUFFER_HEADER (SGCN_BUFFER(sgcn_buffer_header_t, 0))
/* starting address of SRAM, will be set by the init_sram_begin function */
static uintptr_t sram_begin;
/*
* starting address of the SGCN buffer, will be set by the
* init_sgcn_buffer_begin function
*/
static uintptr_t sgcn_buffer_begin;
/*
* Ensures that writing to the buffer and consequent update of the write pointer
* are together one atomic operation.
*/
SPINLOCK_INITIALIZE(sgcn_output_lock);
static void sgcn_putchar(struct chardev * cd, const char c);
/** character device operations */
static chardev_operations_t sgcn_ops = {
.suspend = NULL,
.resume = NULL,
.write = sgcn_putchar,
.read = NULL
};
/** SGCN character device */
chardev_t sgcn_stdout;
/**
* Initializes the starting address of SRAM.
*
* The SRAM starts 0x900000 + C bytes behind the SBBC start in the
* physical memory, where C is the value read from the "iosram-toc"
* property of the "/chosen" OBP node. The sram_begin variable will
* be set to the virtual address which maps to the SRAM physical
* address.
*/
static void init_sram_begin(void)
{
ofw_tree_node_t *chosen;
ofw_tree_property_t *iosram_toc;
chosen = ofw_tree_lookup("/chosen");
if (!chosen)
panic("Can't find /chosen.\n");
iosram_toc = ofw_tree_getprop(chosen, "iosram-toc");
if (!iosram_toc)
panic("Can't find property \"iosram-toc\".\n");
if (!iosram_toc->value)
panic("Can't find SRAM TOC.\n");
sram_begin = hw_map(
SBBC_START + SBBC_SRAM_OFFSET
+ *((uint32_t *) iosram_toc->value),
128 * 1024);
}
/**
* Initializes the starting address of the SGCN buffer.
*
* The offset of the SGCN buffer within SRAM is obtained from the
* SRAM table of contents. The table of contents contains
* information about several buffers, among which there is an OBP
* console buffer - this one will be used as the SGCN buffer.
*/
static void sgcn_buffer_begin_init(void)
{
init_sram_begin();
ASSERT
(strcmp(SRAM_TOC
->magic
, SRAM_TOC_MAGIC
) == 0);
/* lookup TOC entry with the correct key */
uint32_t i;
for (i = 0; i < MAX_TOC_ENTRIES; i++) {
if (strcmp(SRAM_TOC
->keys
[i
].
key, CONSOLE_KEY
) == 0) break;
}
ASSERT(i < MAX_TOC_ENTRIES);
sgcn_buffer_begin = sram_begin + SRAM_TOC->keys[i].offset;
}
/**
* Writes a single character to the SGCN (circular) output buffer
* and updates the output write pointer so that SGCN gets to know
* that the character has been written.
*/
static void sgcn_do_putchar(const char c)
{
uint32_t begin = SGCN_BUFFER_HEADER->out_begin;
uint32_t end = SGCN_BUFFER_HEADER->out_end;
uint32_t size = end - begin;
/* we need pointers to volatile variables */
volatile char *buf_ptr = (volatile char *)
SGCN_BUFFER(char, SGCN_BUFFER_HEADER->out_wrptr);
volatile uint32_t *out_wrptr_ptr = &(SGCN_BUFFER_HEADER->out_wrptr);
volatile uint32_t *out_rdptr_ptr = &(SGCN_BUFFER_HEADER->out_rdptr);
/*
* Write the character and increment the write pointer modulo the
* output buffer size. Note that if we are to rewrite a character
* which has not been read by the SGCN controller yet (i.e. the output
* buffer is full), we need to wait until the controller reads some more
* characters. We wait actively, which means that all threads waiting
* for the lock are blocked. However, this situation is
* 1) rare - the output buffer is big, so filling the whole
* output buffer is improbable
* 2) short-lasting - it will take the controller only a fraction
* of millisecond to pick the unread characters up
* 3) not serious - the blocked threads are those that print something
* to user console, which is not a time-critical operation
*/
uint32_t new_wrptr = (((*out_wrptr_ptr) - begin + 1) % size) + begin;
while (*out_rdptr_ptr == new_wrptr)
;
*buf_ptr = c;
*out_wrptr_ptr = new_wrptr;
}
/**
* SGCN output operation. Prints a single character to the SGCN. If the line
* feed character is written ('\n'), the carriage return character ('\r') is
* written straight away.
*/
static void sgcn_putchar(struct chardev * cd, const char c)
{
spinlock_lock(&sgcn_output_lock);
sgcn_do_putchar(c);
if (c == '\n') {
sgcn_do_putchar('\r');
}
spinlock_unlock(&sgcn_output_lock);
}
/**
* A public function which initializes I/O from/to Serengeti console
* and sets it as a default input/output.
*/
void sgcn_init(void)
{
sgcn_buffer_begin_init();
chardev_initialize("sgcn_output", &sgcn_stdout, &sgcn_ops);
stdout = &sgcn_stdout;
printf("SGCN buffer begin = %d, in read ptr = %" PRIu32
".", sgcn_buffer_begin
, SGCN_BUFFER_HEADER
->in_wrptr
); }
/** @}
*/