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Commit e0cf9576 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt
Browse files

powerpc/powernv: Fix indirect XSCOM unmangling 



We need to unmangle the full address, not just the register
number, and we also need to support the real indirect bit
being set for in-kernel uses.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@vger.kernel.org> [v3.13]
parent 2f3f38e4

arch/powerpc/platforms/powernv/opal-xscom.c

+12 −9
Original line number Diff line number Diff line
@@ -71,11 +71,11 @@ static int opal_xscom_err_xlate(int64_t rc) 
	}

}



static u64 opal_scom_unmangle(u64 reg)

static u64 opal_scom_unmangle(u64 addr)

{

	/*

	 * XSCOM indirect addresses have the top bit set. Additionally

	 * the reset of the top 3 nibbles is always 0.

	 * the rest of the top 3 nibbles is always 0.

	 *

	 * Because the debugfs interface uses signed offsets and shifts

	 * the address left by 3, we basically cannot use the top 4 bits
@@ -86,10 +86,13 @@ static u64 opal_scom_unmangle(u64 reg) 
	 * conversion here. To leave room for further xscom address

	 * expansion, we only clear out the top byte

	 *

	 * For in-kernel use, we also support the real indirect bit, so

	 * we test for any of the top 5 bits

	 *

	 */

	if (reg & (1ull << 59))

		reg = (reg & ~(0xffull << 56)) | (1ull << 63);

	return reg;

	if (addr & (0x1full << 59))

		addr = (addr & ~(0xffull << 56)) | (1ull << 63);

	return addr;

}



static int opal_scom_read(scom_map_t map, u64 reg, u64 *value)
@@ -98,8 +101,8 @@ static int opal_scom_read(scom_map_t map, u64 reg, u64 *value) 
	int64_t rc;

	__be64 v;



	reg = opal_scom_unmangle(reg);

	rc = opal_xscom_read(m->chip, m->addr + reg, (__be64 *)__pa(&v));

	reg = opal_scom_unmangle(m->addr + reg);

	rc = opal_xscom_read(m->chip, reg, (__be64 *)__pa(&v));

	*value = be64_to_cpu(v);

	return opal_xscom_err_xlate(rc);

}
@@ -109,8 +112,8 @@ static int opal_scom_write(scom_map_t map, u64 reg, u64 value) 
	struct opal_scom_map *m = map;

	int64_t rc;



	reg = opal_scom_unmangle(reg);

	rc = opal_xscom_write(m->chip, m->addr + reg, value);

	reg = opal_scom_unmangle(m->addr + reg);

	rc = opal_xscom_write(m->chip, reg, value);

	return opal_xscom_err_xlate(rc);

}