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intel_th: msu: Preserve pre-existing buffer configuration 

The MSU configuration registers may contain buffer address/size set by
the BIOS or an external hardware debugger, which may want to take over
tracing from the driver when the driver is not actively tracing.

Preserve these settings when not actively tracing.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190705141425.19894-6-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexander Shishkin 2019-07-05 17:14:25 +03:00 committed by Greg Kroah-Hartman
parent ed5207afc5
commit 092f47c383
1 changed files with 7 additions and 2 deletions
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9
drivers/hwtracing/intel_th/msu.c
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@ -143,6 +143,8 @@ struct msc {
unsigned int single_wrap : 1;
void *base;
dma_addr_t base_addr;
u32 orig_addr;
u32 orig_sz;
/* <0: no buffer, 0: no users, >0: active users */
atomic_t user_count;
@ -767,6 +769,9 @@ static int msc_configure(struct msc *msc)
msc_buffer_clear_hw_header(msc);
}
msc->orig_addr = ioread32(msc->reg_base + REG_MSU_MSC0BAR);
msc->orig_sz = ioread32(msc->reg_base + REG_MSU_MSC0SIZE);
reg = msc->base_addr >> PAGE_SHIFT;
iowrite32(reg, msc->reg_base + REG_MSU_MSC0BAR);
@ -841,8 +846,8 @@ static void msc_disable(struct msc *msc)
msc->enabled = 0;
iowrite32(0, msc->reg_base + REG_MSU_MSC0BAR);
iowrite32(0, msc->reg_base + REG_MSU_MSC0SIZE);
iowrite32(msc->orig_addr, msc->reg_base + REG_MSU_MSC0BAR);
iowrite32(msc->orig_sz, msc->reg_base + REG_MSU_MSC0SIZE);
dev_dbg(msc_dev(msc), "MSCnNWSA: %08x\n",
ioread32(msc->reg_base + REG_MSU_MSC0NWSA));