[PATCH 4.4 057/105] MIPS: BCM47XX: Enable 74K Core ExternalSync for PCIe erratum

[PATCH 4.4 057/105] MIPS: BCM47XX: Enable 74K Core ExternalSync for PCIe erratum

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tokunori Ikegami <ikegami@allied-telesis.co.jp>

commit 2a027b47dba6b77ab8c8e47b589ae9bbc5ac6175 upstream.

The erratum and workaround are described by BCM5300X-ES300-RDS.pdf as
below.

  R10: PCIe Transactions Periodically Fail

    Description: The BCM5300X PCIe does not maintain transaction ordering.
                 This may cause PCIe transaction failure.
    Fix Comment: Add a dummy PCIe configuration read after a PCIe
                 configuration write to ensure PCIe configuration access
                 ordering. Set ES bit of CP0 configu7 register to enable
                 sync function so that the sync instruction is functional.
    Resolution:  hndpci.c: extpci_write_config()
                 hndmips.c: si_mips_init()
                 mipsinc.h CONF7_ES

This is fixed by the CFE MIPS bcmsi chipset driver also for BCM47XX.
Also the dummy PCIe configuration read is already implemented in the
Linux BCMA driver.

Enable ExternalSync in Config7 when CONFIG_BCMA_DRIVER_PCI_HOSTMODE=y
too so that the sync instruction is externalised.

Signed-off-by: Tokunori Ikegami <ikegami@allied-telesis.co.jp>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: Rafał Miłecki <zajec5@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/19461/
Signed-off-by: James Hogan <jhogan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/bcm47xx/setup.c        |    6 ++++++
 arch/mips/include/asm/mipsregs.h |    3 +++
 2 files changed, 9 insertions(+)

--- a/arch/mips/bcm47xx/setup.c
+++ b/arch/mips/bcm47xx/setup.c
@@ -249,6 +249,12 @@ static int __init bcm47xx_cpu_fixes(void
 		 */
 		if (bcm47xx_bus.bcma.bus.chipinfo.id == BCMA_CHIP_ID_BCM4706)
 			cpu_wait = NULL;
+
+		/*
+		 * BCM47XX Erratum "R10: PCIe Transactions Periodically Fail"
+		 * Enable ExternalSync for sync instruction to take effect
+		 */
+		set_c0_config7(MIPS_CONF7_ES);
 		break;
 #endif
 	}
--- a/arch/mips/include/asm/mipsregs.h
+++ b/arch/mips/include/asm/mipsregs.h
@@ -605,6 +605,8 @@
 #define MIPS_CONF7_WII		(_ULCAST_(1) << 31)
 
 #define MIPS_CONF7_RPS		(_ULCAST_(1) << 2)
+/* ExternalSync */
+#define MIPS_CONF7_ES		(_ULCAST_(1) << 8)
 
 #define MIPS_CONF7_IAR		(_ULCAST_(1) << 10)
 #define MIPS_CONF7_AR		(_ULCAST_(1) << 16)
@@ -2012,6 +2014,7 @@ __BUILD_SET_C0(status)
 __BUILD_SET_C0(cause)
 __BUILD_SET_C0(config)
 __BUILD_SET_C0(config5)
+__BUILD_SET_C0(config7)
 __BUILD_SET_C0(intcontrol)
 __BUILD_SET_C0(intctl)
 __BUILD_SET_C0(srsmap)

[PATCH 4.4 059/105] MIPS: io: Add barrier after register read in inX()

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Huacai Chen <chenhc@lemote.com>

commit 18f3e95b90b28318ef35910d21c39908de672331 upstream.

While a barrier is present in the outX() functions before the register
write, a similar barrier is missing in the inX() functions after the
register read. This could allow memory accesses following inX() to
observe stale data.

This patch is very similar to commit a1cc7034e33d12dc1 ("MIPS: io: Add
barrier after register read in readX()"). Because war_io_reorder_wmb()
is both used by writeX() and outX(), if readX() need a barrier then so
does inX().

Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Patchwork: https://patchwork.linux-mips.org/patch/19516/
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: James Hogan <james.hogan@mips.com>
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: Huacai Chen <chenhuacai@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/include/asm/io.h |    2 ++
 1 file changed, 2 insertions(+)

--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -411,6 +411,8 @@ static inline type pfx##in##bwlq##p(unsi
 	__val = *__addr;						\
 	slow;								\
 									\
+	/* prevent prefetching of coherent DMA data prematurely */	\
+	rmb();								\
 	return pfx##ioswab##bwlq(__addr, __val);			\
 }
 

[PATCH 4.4 060/105] time: Make sure jiffies_to_msecs() preserves non-zero time periods

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Geert Uytterhoeven <geert@linux-m68k.org>

commit abcbcb80cd09cd40f2089d912764e315459b71f7 upstream.

For the common cases where 1000 is a multiple of HZ, or HZ is a multiple of
1000, jiffies_to_msecs() never returns zero when passed a non-zero time
period.

However, if HZ > 1000 and not an integer multiple of 1000 (e.g. 1024 or
1200, as used on alpha and DECstation), jiffies_to_msecs() may return zero
for small non-zero time periods.  This may break code that relies on
receiving back a non-zero value.

jiffies_to_usecs() does not need such a fix: one jiffy can only be less
than one µs if HZ > 1000000, and such large values of HZ are already
rejected at build time, twice:

  - include/linux/jiffies.h does #error if HZ >= 12288,
  - kernel/time/time.c has BUILD_BUG_ON(HZ > USEC_PER_SEC).

Broken since forever.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: linux-alpha@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180622143357.7495-1-geert@linux-m68k.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/time/time.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -28,6 +28,7 @@
  */
 
 #include <linux/export.h>
+#include <linux/kernel.h>
 #include <linux/timex.h>
 #include <linux/capability.h>
 #include <linux/timekeeper_internal.h>
@@ -258,9 +259,10 @@ unsigned int jiffies_to_msecs(const unsi
 	return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
 #else
 # if BITS_PER_LONG == 32
-	return (HZ_TO_MSEC_MUL32 * j) >> HZ_TO_MSEC_SHR32;
+	return (HZ_TO_MSEC_MUL32 * j + (1ULL << HZ_TO_MSEC_SHR32) - 1) >>
+	       HZ_TO_MSEC_SHR32;
 # else
-	return (j * HZ_TO_MSEC_NUM) / HZ_TO_MSEC_DEN;
+	return DIV_ROUND_UP(j * HZ_TO_MSEC_NUM, HZ_TO_MSEC_DEN);
 # endif
 #endif
 }