[PATCH v3 0/4] Atari kernel-in-FastRAM patches v3

[Michael Schmitz]

Hi Geert,

changes to stram.c and atafb.c patches as requested. The external_addr
case is still untested - may have other bugs that I've not seen when
changing the external_addr types.

CC to the relevant lists for floppy and SCSI patches.

Cheers,

Michael

[Michael Schmitz]

With the kernel running from FastRAM instead of ST-RAM, none of ST-RAM is
mapped by mem_init, and DMA-addressable buffer must be mapped by ioremap.

Use platform specific virt/phys translation helpers for this case.

Signed-off-by: Michael Schmitz <***@debian.org>
Cc: linux-***@vger.kernel.org
---
drivers/scsi/atari_scsi.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/atari_scsi.c b/drivers/scsi/atari_scsi.c
index 296c936..a8d721f 100644
--- a/drivers/scsi/atari_scsi.c
+++ b/drivers/scsi/atari_scsi.c
@@ -639,7 +639,7 @@ static int __init atari_scsi_detect(struct scsi_host_template *host)
"double buffer\n");
return 0;
}
- atari_dma_phys_buffer = virt_to_phys(atari_dma_buffer);
+ atari_dma_phys_buffer = atari_stram_to_phys(atari_dma_buffer);
atari_dma_orig_addr = 0;
}
#endif

[Michael Schmitz]

With the kernel loaded to FastRAM (TT-RAM), none of the ST-RAM
address range is mapped by init_mem, and ST-RAM is not accessible
through the normal allocation pathways as a result.

Implement ST-RAM pool allocation to be based on physical addresses
always (it already was when the kernel was loaded in ST-RAM).
Return kernel virtual addresses as per normal.

The current test for the kernel residing in ST-RAM always returns
true. Use the bootinfo memory chunk order instead - with the kernel
in FastRAM, ST-RAM (phys. 0x0) is not the first chunk.

In case the kernel is running from FastRAM, delay mapping of ST-RAM
pool until after mem_init.

Provide helper functions for those users of ST-RAM that need
to be aware of the backing physical addresses.

Kudos to Geert for his hints on getting this started.

Signed-off-by: Michael Schmitz <***@debian.org>
---
arch/m68k/atari/stram.c | 71 ++++++++++++++++++++++++++--------
arch/m68k/include/asm/atari_stram.h | 2 +
2 files changed, 56 insertions(+), 17 deletions(-)

diff --git a/arch/m68k/atari/stram.c b/arch/m68k/atari/stram.c
index 0810c8d..5f8cb5a 100644
--- a/arch/m68k/atari/stram.c
+++ b/arch/m68k/atari/stram.c
@@ -47,6 +47,7 @@ static struct resource stram_pool = {

static unsigned long pool_size = 1024*1024;

+static unsigned long stram_virt_offset;

static int __init atari_stram_setup(char *arg)
{
@@ -67,14 +68,12 @@ early_param("stram_pool", atari_stram_setup);
void __init atari_stram_init(void)
{
int i;
- void *stram_start;

/*
* determine whether kernel code resides in ST-RAM
* (then ST-RAM is the first memory block at virtual 0x0)
*/
- stram_start = phys_to_virt(0);
- kernel_in_stram = (stram_start == 0);
+ kernel_in_stram = (m68k_memory[0].addr == 0);

for (i = 0; i < m68k_num_memory; ++i) {
if (m68k_memory[i].addr == 0) {
@@ -89,24 +88,62 @@ void __init atari_stram_init(void)

/*
* This function is called from setup_arch() to reserve the pages needed for
- * ST-RAM management.
+ * ST-RAM management, if the kernel resides in ST-RAM.
*/
void __init atari_stram_reserve_pages(void *start_mem)
{
- /*
- * always reserve first page of ST-RAM, the first 2 KiB are
- * supervisor-only!
- */
- if (!kernel_in_stram)
- reserve_bootmem(0, PAGE_SIZE, BOOTMEM_DEFAULT);
+ if (kernel_in_stram) {
+ pr_debug("atari_stram pool: kernel in ST-RAM, using alloc_bootmem!\n");
+ stram_pool.start = (resource_size_t)alloc_bootmem_low_pages(pool_size);
+ stram_pool.end = stram_pool.start + pool_size - 1;
+ request_resource(&iomem_resource, &stram_pool);
+ stram_virt_offset = 0;
+ pr_debug("atari_stram pool: size = %lu bytes, resource = %pR\n",
+ pool_size, &stram_pool);
+ pr_debug("atari_stram pool: stram_virt_offset = %lx\n",
+ stram_virt_offset);
+ }
+}

- stram_pool.start = (resource_size_t)alloc_bootmem_low_pages(pool_size);
- stram_pool.end = stram_pool.start + pool_size - 1;
- request_resource(&iomem_resource, &stram_pool);

- pr_debug("atari_stram pool: size = %lu bytes, resource = %pR\n",
- pool_size, &stram_pool);
+/*
+ * This function is called as arch initcall to reserve the pages needed for
+ * ST-RAM management, if the kernel does not reside in ST-RAM.
+ */
+int __init atari_stram_map_pages(void)
+{
+ if (!kernel_in_stram) {
+ /*
+ * Skip page 0, as the fhe first 2 KiB are supervisor-only!
+ */
+ pr_debug("atari_stram pool: kernel not in ST-RAM, using ioremap!\n");
+ stram_pool.start = PAGE_SIZE;
+ stram_pool.end = stram_pool.start + pool_size - 1;
+ request_resource(&iomem_resource, &stram_pool);
+ stram_virt_offset = (unsigned long) ioremap(stram_pool.start,
+ resource_size(&stram_pool)) - stram_pool.start;
+ pr_debug("atari_stram pool: size = %lu bytes, resource = %pR\n",
+ pool_size, &stram_pool);
+ pr_debug("atari_stram pool: stram_virt_offset = %lx\n",
+ stram_virt_offset);
+ }
+ return 0;
+}
+arch_initcall(atari_stram_map_pages);
+
+
+void *atari_stram_to_virt(unsigned long phys)
+{
+ return (void *)(phys + stram_virt_offset);
+}
+EXPORT_SYMBOL(atari_stram_to_virt);
+
+
+unsigned long atari_stram_to_phys(void *virt)
+{
+ return (unsigned long)(virt - stram_virt_offset);
}
+EXPORT_SYMBOL(atari_stram_to_phys);


void *atari_stram_alloc(unsigned long size, const char *owner)
@@ -134,14 +171,14 @@ void *atari_stram_alloc(unsigned long size, const char *owner)
}

pr_debug("atari_stram_alloc: returning %pR\n", res);
- return (void *)res->start;
+ return atari_stram_to_virt(res->start);
}
EXPORT_SYMBOL(atari_stram_alloc);


void atari_stram_free(void *addr)
{
- unsigned long start = (unsigned long)addr;
+ unsigned long start = atari_stram_to_phys(addr);
struct resource *res;
unsigned long size;

diff --git a/arch/m68k/include/asm/atari_stram.h b/arch/m68k/include/asm/atari_stram.h
index 62e2759..4e771c2 100644
--- a/arch/m68k/include/asm/atari_stram.h
+++ b/arch/m68k/include/asm/atari_stram.h
@@ -8,6 +8,8 @@
/* public interface */
void *atari_stram_alloc(unsigned long size, const char *owner);
void atari_stram_free(void *);
+void *atari_stram_to_virt(unsigned long phys);
+unsigned long atari_stram_to_phys(void *);

/* functions called internally by other parts of the kernel */
void atari_stram_init(void);

[Michael Schmitz]

With the kernel running from FastRAM instead of ST-RAM, none of ST-RAM is
mapped by mem_init, and DMA-addressable buffer must be mapped by ioremap.

Use platform specific virt/phys translation helpers for this case.

Signed-off-by: Michael Schmitz <***@debian.org>
Cc: linux-***@vger.kernel.org
---
drivers/block/ataflop.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c
index 0e30c6e..f54655a 100644
--- a/drivers/block/ataflop.c
+++ b/drivers/block/ataflop.c
@@ -1952,7 +1952,7 @@ static int __init atari_floppy_init (void)
goto Enomem;
}
TrackBuffer = DMABuffer + 512;
- PhysDMABuffer = virt_to_phys(DMABuffer);
+ PhysDMABuffer = atari_stram_to_phys(DMABuffer);
PhysTrackBuffer = virt_to_phys(TrackBuffer);
BufferDrive = BufferSide = BufferTrack = -1;

[Michael Schmitz]

The new atari_stram_alloc interface returns kernel virtual addresses
even if the kernel runs in FastRAM. These addresses are not
guaranteed to be identical with the physical addresses. Since ST-RAM
mappings have not been set up by mem_init, virt_to_phys() and its
cousin do not work and the atari_stram_to_phys() etc. helpers must
be used to determine physical addresses.

fb.fix->smem_start needs physical addresses, fb.par->screen_base
needs virtual addresses. Take care of the virt-to-phys conversion
both on fb init and par changes.

Signed-off-by: Michael Schmitz <***@debian.org>
---
drivers/video/atafb.c | 49 ++++++++++++++++++++++++++-----------------------
1 files changed, 26 insertions(+), 23 deletions(-)

diff --git a/drivers/video/atafb.c b/drivers/video/atafb.c
index e21d1f5..bde9c31 100644
--- a/drivers/video/atafb.c
+++ b/drivers/video/atafb.c
@@ -191,7 +191,7 @@ static struct fb_info fb_info = {
};

static void *screen_base; /* base address of screen */
-static void *real_screen_base; /* (only for Overscan) */
+static unsigned long phys_screen_base; /* (only for Overscan) */

static int screen_len;

@@ -213,7 +213,8 @@ static unsigned int external_yres;
*/
static unsigned int external_depth;
static int external_pmode;
-static void *external_addr;
+static void *external_screen_base;
+static unsigned long external_addr;
static unsigned long external_len;
static unsigned long external_vgaiobase;
static unsigned int external_bitspercol = 6;
@@ -592,7 +593,7 @@ static int tt_encode_fix(struct fb_fix_screeninfo *fix, struct atafb_par *par)
int mode;

strcpy(fix->id, "Atari Builtin");
- fix->smem_start = (unsigned long)real_screen_base;
+ fix->smem_start = phys_screen_base;
fix->smem_len = screen_len;
fix->type = FB_TYPE_INTERLEAVED_PLANES;
fix->type_aux = 2;
@@ -790,7 +791,7 @@ static void tt_get_par(struct atafb_par *par)
addr = ((shifter.bas_hi & 0xff) << 16) |
((shifter.bas_md & 0xff) << 8) |
((shifter.bas_lo & 0xff));
- par->screen_base = phys_to_virt(addr);
+ par->screen_base = atari_stram_to_virt(addr);
}

static void tt_set_par(struct atafb_par *par)
@@ -888,7 +889,7 @@ static int falcon_encode_fix(struct fb_fix_screeninfo *fix,
struct atafb_par *par)
{
strcpy(fix->id, "Atari Builtin");
- fix->smem_start = (unsigned long)real_screen_base;
+ fix->smem_start = phys_screen_base;
fix->smem_len = screen_len;
fix->type = FB_TYPE_INTERLEAVED_PLANES;
fix->type_aux = 2;
@@ -1584,7 +1585,7 @@ static void falcon_get_par(struct atafb_par *par)
addr = (shifter.bas_hi & 0xff) << 16 |
(shifter.bas_md & 0xff) << 8 |
(shifter.bas_lo & 0xff);
- par->screen_base = phys_to_virt(addr);
+ par->screen_base = atari_stram_to_virt(addr);

/* derived parameters */
hw->ste_mode = (hw->f_shift & 0x510) == 0 && hw->st_shift == 0x100;
@@ -1814,7 +1815,7 @@ static int stste_encode_fix(struct fb_fix_screeninfo *fix,
int mode;

strcpy(fix->id, "Atari Builtin");
- fix->smem_start = (unsigned long)real_screen_base;
+ fix->smem_start = phys_screen_base;
fix->smem_len = screen_len;
fix->type = FB_TYPE_INTERLEAVED_PLANES;
fix->type_aux = 2;
@@ -1980,7 +1981,7 @@ static void stste_get_par(struct atafb_par *par)
((shifter.bas_md & 0xff) << 8);
if (ATARIHW_PRESENT(EXTD_SHIFTER))
addr |= (shifter.bas_lo & 0xff);
- par->screen_base = phys_to_virt(addr);
+ par->screen_base = atari_stram_to_virt(addr);
}

static void stste_set_par(struct atafb_par *par)
@@ -2039,7 +2040,7 @@ static int stste_detect(void)
static void stste_set_screen_base(void *s_base)
{
unsigned long addr;
- addr = virt_to_phys(s_base);
+ addr = atari_stram_to_phys(s_base);
/* Setup Screen Memory */
shifter.bas_hi = (unsigned char)((addr & 0xff0000) >> 16);
shifter.bas_md = (unsigned char)((addr & 0x00ff00) >> 8);
@@ -2113,7 +2114,7 @@ static void st_ovsc_switch(void)
static int ext_encode_fix(struct fb_fix_screeninfo *fix, struct atafb_par *par)
{
strcpy(fix->id, "Unknown Extern");
- fix->smem_start = (unsigned long)external_addr;
+ fix->smem_start = external_addr;
fix->smem_len = PAGE_ALIGN(external_len);
if (external_depth == 1) {
fix->type = FB_TYPE_PACKED_PIXELS;
@@ -2213,7 +2214,7 @@ static int ext_encode_var(struct fb_var_screeninfo *var, struct atafb_par *par)

static void ext_get_par(struct atafb_par *par)
{
- par->screen_base = external_addr;
+ par->screen_base =external_screen_base;
}

static void ext_set_par(struct atafb_par *par)
@@ -2286,7 +2287,7 @@ static void set_screen_base(void *s_base)
{
unsigned long addr;

- addr = virt_to_phys(s_base);
+ addr = atari_stram_to_phys(s_base);
/* Setup Screen Memory */
shifter.bas_hi = (unsigned char)((addr & 0xff0000) >> 16);
shifter.bas_md = (unsigned char)((addr & 0x00ff00) >> 8);
@@ -2433,7 +2434,9 @@ static void atafb_set_disp(struct fb_info *info)
atafb_get_var(&info->var, info);
atafb_get_fix(&info->fix, info);

- info->screen_base = (void *)info->fix.smem_start;
+ /* Note: smem_start derives from phys_screen_base, not screen_base! */
+ info->screen_base = (external_addr ? external_screen_base :
+ atari_stram_to_virt(info->fix.smem_start));
}

static int atafb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
@@ -2904,7 +2907,7 @@ static void __init atafb_setup_ext(char *spec)
external_yres = yres;
external_depth = depth;
external_pmode = planes;
- external_addr = (void *)addr;
+ external_addr = addr;
external_len = len;

if (external_card_type == IS_MV300) {
@@ -3166,30 +3169,30 @@ int __init atafb_init(void)
memset(screen_base, 0, mem_req);
pad = -(unsigned long)screen_base & (PAGE_SIZE - 1);
screen_base += pad;
- real_screen_base = screen_base + ovsc_offset;
+ phys_screen_base = atari_stram_to_phys(screen_base + ovsc_offset);
screen_len = (mem_req - pad - ovsc_offset) & PAGE_MASK;
st_ovsc_switch();
if (CPU_IS_040_OR_060) {
/* On a '040+, the cache mode of video RAM must be set to
* write-through also for internal video hardware! */
- cache_push(virt_to_phys(screen_base), screen_len);
+ cache_push(atari_stram_to_phys(screen_base), screen_len);
kernel_set_cachemode(screen_base, screen_len,
IOMAP_WRITETHROUGH);
}
- printk("atafb: screen_base %p real_screen_base %p screen_len %d\n",
- screen_base, real_screen_base, screen_len);
+ printk("atafb: screen_base %p phys_screen_base %lx screen_len %d\n",
+ screen_base, phys_screen_base, screen_len);
#ifdef ATAFB_EXT
} else {
/* Map the video memory (physical address given) to somewhere
* in the kernel address space.
*/
- external_addr = ioremap_writethrough((unsigned long)external_addr,
+ external_screen_base = ioremap_writethrough((unsigned long)external_addr,
external_len);
if (external_vgaiobase)
external_vgaiobase =
(unsigned long)ioremap(external_vgaiobase, 0x10000);
- screen_base =
- real_screen_base = external_addr;
+ screen_base = external_screen_base;
+ phys_screen_base = external_addr;
screen_len = external_len & PAGE_MASK;
memset (screen_base, 0, external_len);
}
@@ -3235,8 +3238,8 @@ int __init atafb_init(void)
if (register_framebuffer(&fb_info) < 0) {
#ifdef ATAFB_EXT
if (external_addr) {
- iounmap(external_addr);
- external_addr = NULL;
+ iounmap(external_screen_base);
+ external_addr = 0;
}
if (external_vgaiobase) {
iounmap((void*)external_vgaiobase);

[Geert Uytterhoeven]

Hi Michael,

Post by Michael Schmitz
The new atari_stram_alloc interface returns kernel virtual addresses
even if the kernel runs in FastRAM. These addresses are not
guaranteed to be identical with the physical addresses. Since ST-RAM
mappings have not been set up by mem_init, virt_to_phys() and its
cousin do not work and the atari_stram_to_phys() etc. helpers must
be used to determine physical addresses.

Thanks!

Post by Michael Schmitz
@@ -2213,7 +2214,7 @@ static int ext_encode_var(struct fb_var_screeninfo *var, struct atafb_par *par)
static void ext_get_par(struct atafb_par *par)
{
- par->screen_base = external_addr;
+ par->screen_base =external_screen_base;

I'll add the missing space after "=".

Post by Michael Schmitz
+ external_screen_base = ioremap_writethrough((unsigned long)external_addr,
external_len);

I'll remove the now superfluous cast.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ***@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

[Michael Schmitz]

Hi Geert,


On Mon, Mar 31, 2014 at 10:12 PM, Geert Uytterhoeven

Post by Geert Uytterhoeven
Hi Michael,

Post by Michael Schmitz
The new atari_stram_alloc interface returns kernel virtual addresses
even if the kernel runs in FastRAM. These addresses are not
guaranteed to be identical with the physical addresses. Since ST-RAM
mappings have not been set up by mem_init, virt_to_phys() and its
cousin do not work and the atari_stram_to_phys() etc. helpers must
be used to determine physical addresses.

Thanks!

Post by Michael Schmitz
@@ -2213,7 +2214,7 @@ static int ext_encode_var(struct fb_var_screeninfo *var, struct atafb_par *par)
static void ext_get_par(struct atafb_par *par)
{
- par->screen_base = external_addr;
+ par->screen_base =external_screen_base;

I'll add the missing space after "=".

Post by Michael Schmitz
+ external_screen_base = ioremap_writethrough((unsigned long)external_addr,
external_len);

I'll remove the now superfluous cast.

Thanks, much appreciated!

Cheers,

Michael

[Geert Uytterhoeven]

Hi Michael,

Post by Michael Schmitz
changes to stram.c and atafb.c patches as requested. The external_addr
case is still untested - may have other bugs that I've not seen when
changing the external_addr types.
CC to the relevant lists for floppy and SCSI patches.

Thanks, applied and queued for 3.16.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ***@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

[Michael Schmitz]

Hi Geert,

On Tue, May 27, 2014 at 8:56 AM, Geert Uytterhoeven

Post by Geert Uytterhoeven
Hi Michael,

Post by Michael Schmitz
changes to stram.c and atafb.c patches as requested. The external_addr
case is still untested - may have other bugs that I've not seen when
changing the external_addr types.
CC to the relevant lists for floppy and SCSI patches.

Thanks, applied and queued for 3.16.

Thank you - anyone testing these please note that the Falcon SCSI DMA
dribble buffer handling in the SCSI patch is still faulty. You should
_not_ attempt to use SCSI when running the kernel in FastRAM.

Cheers,

Michael

[Michael Schmitz]

Post by Michael Schmitz
Hi Geert,
On Tue, May 27, 2014 at 8:56 AM, Geert Uytterhoeven

Post by Geert Uytterhoeven
Hi Michael,

Post by Michael Schmitz
changes to stram.c and atafb.c patches as requested. The external_addr
case is still untested - may have other bugs that I've not seen when
changing the external_addr types.
CC to the relevant lists for floppy and SCSI patches.

Thanks, applied and queued for 3.16.

Thank you - anyone testing these please note that the Falcon SCSI DMA
dribble buffer handling in the SCSI patch is still faulty. You should
_not_ attempt to use SCSI when running the kernel in FastRAM.

Found the error, most likely - when the kernel runs in FastRAM,
m68k_num_memory is == 1. Is there a way to access the bootinfo view of
the number of memory chunks after the MMU init code has tweaked
m68k_num_memory, Geert?

Cheers,

Michael

[Geert Uytterhoeven]

Hi Michael,

Post by Michael Schmitz

Post by Michael Schmitz
Thank you - anyone testing these please note that the Falcon SCSI DMA
dribble buffer handling in the SCSI patch is still faulty. You should
_not_ attempt to use SCSI when running the kernel in FastRAM.

Found the error, most likely - when the kernel runs in FastRAM,
m68k_num_memory is == 1. Is there a way to access the bootinfo view of the
number of memory chunks after the MMU init code has tweaked m68k_num_memory,
Geert?

You mean the ones that were removed due to "Ignoring memory chunk"?

No, bootinfo is gone, unless saved for kexec with CONFIG_BOOTINFO_PROC=y.

What exactly is the issue?

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ***@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

[Michael Schmitz]

Hi Geert,

Post by Geert Uytterhoeven

Post by Michael Schmitz
Found the error, most likely - when the kernel runs in FastRAM,
m68k_num_memory is == 1. Is there a way to access the bootinfo view of the
number of memory chunks after the MMU init code has tweaked m68k_num_memory,
Geert?

You mean the ones that were removed due to "Ignoring memory chunk"?

These ones exactly.

Post by Geert Uytterhoeven
No, bootinfo is gone, unless saved for kexec with CONFIG_BOOTINFO_PROC=y.
What exactly is the issue?

When deciding whether a ST-RAM DMA buffer needs to be allocated, the
Atari SCSI driver checks whether there's more than a single chunk of
RAM (there's always ST-RAM, so the second one indicates FastRAM).
That's no longer a good test now with the kernel capable of running
from FastRAM (and the ST-RAM chunk being dropped in MM init).

Maybe we need another variable to hold the number of memory chunks
before adjustment. Or look at size or physical base address of the
first chunk...

Cheers,

Michael

Post by Geert Uytterhoeven
Gr{oetje,eeting}s,
Geert
--
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

[Geert Uytterhoeven]

Hi Michael,

Post by Michael Schmitz
When deciding whether a ST-RAM DMA buffer needs to be allocated, the
Atari SCSI driver checks whether there's more than a single chunk of
RAM (there's always ST-RAM, so the second one indicates FastRAM).
That's no longer a good test now with the kernel capable of running
from FastRAM (and the ST-RAM chunk being dropped in MM init).
Maybe we need another variable to hold the number of memory chunks
before adjustment. Or look at size or physical base address of the
first chunk...

That's why DMA masks have been invented. The one in atari_scsi.c seems
to have the bits inverted, compared to all other places in the kernel.

But indeed, that doesn't help for the initial check:

if (MACH_IS_ATARI && ATARIHW_PRESENT(ST_SCSI) &&
!ATARIHW_PRESENT(EXTD_DMA) && m68k_num_memory > 1) {
atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI");
if (!atari_dma_buffer) {
printk(KERN_ERR "atari_scsi_detect: can't
allocate ST-RAM "
"double buffer\n");
return 0;
}
atari_dma_phys_buffer = virt_to_phys(atari_dma_buffer);
atari_dma_orig_addr = 0;
}

You can loop over m68k_memory[], and check if any chunk lies outside
the first 16 MiB?

If everything fails, you can allocate it unconditionally (it's just
one 4 KiB page).

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ***@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds