After checking all possible call chains to mv_reset_channel here,
my tool finds that mv_reset_channel is never called in atomic context,
namely never in an interrupt handler or holding a spinlock.
Thus mdelay can be replaced with usleep_range to avoid busy wait.
This is found by a static analysis tool named DCNS written by myself.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
In cases where a "drop through" comment was already in place, I replaced
it with a proper "fall through" comment, which is what GCC is expecting
to find.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The pointer ehi is being assigned to a value that is never read
and is redundant. Clean up the code and move the ehi declaration
and initialization to the code block where it is used. Cleans up
clang warning: Value stored to 'ehi' is never read
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This reverts commit 368e5fbdfc.
devm_ioremap_resource() enforces that there are no overlapping
resources, where as devm_ioremap() does not. The sata phy driver needs
a subset of the sata IO address space, so maps some of the sata
address space. As a result, sata_mv now fails to probe, reporting it
cannot get its resources, and so we don't have any SATA disks.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Cc: stable@vger.kernel.org # v4.11+
Signed-off-by: Tejun Heo <tj@kernel.org>
Declare of_device_id structures as const as they are either passed to
the macro MODULE_DEVICE_TABLE or stored in the of_match_table field of a
device_driver structure. This field is of type const, so of_device_id
structures having this property can be made const too.
Cross compiled the files drivers/ata/pata_macio.c and
drivers/ata/pata_mpc52xx.c for powerpc architecture.
Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Convert to devm_ioremap_resource() which provides more consistent error
handling.
Note that devm_ioremap_resource() provides its own error messages.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Here, If devm_ioremap will fail. It will return NULL.
Then hpriv->base = NULL - 0x20000; Kernel can run into
a NULL-pointer dereference. This error check will avoid
NULL pointer dereference.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
If the nr-ports property is missing ata_host_alloc_pinfo is called with
n_ports = 0. This results in host->ports[0] = NULL which later makes
mv_init_host() oops when dereferencing this pointer.
Instead be a bit more cooperative and fail the probing with an error
message.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Replacing dma_pool_alloc and memset with a single call to dma_pool_zalloc
Signed-off-by: Harman Kalra <harman4linux@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Fix the signed issue in mv_write_cached_reg() where the laddr
is assigned from a (long)addr instead of (unsigned long)addr.
Fixes the following warnings:
drivers/ata/sata_mv.c:989:26: warning: cast removes address space of expression
drivers/ata/sata_mv.c:989:26: warning: cast removes address space of expression
drivers/ata/sata_mv.c:989:26: warning: cast removes address space of expression
drivers/ata/sata_mv.c:989:26: warning: cast removes address space of expression
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Tejun Heo <tj@kernel.org>
Commit 9013d64e66 ("ata: sata_mv: fix disk hotplug for Armada
370/XP SoCs") added some manipulation of the LP_PHY_CTL register, but
using magic values. This commit changes the code to use proper
definitions for the LP_PHY_CTL register, which allows to document what
the different bits are doing.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Simon Guinot <simon.guinot@sequanux.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
The phy_power_off() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Tejun Heo <tj@kernel.org>
This patch fixes host drivers to use CONFIG_PM_SLEEP instead of CONFIG_PM
where applicable. Benefits of this change:
* unused code is not being compiled in for CONFIG_PM=y, CONFIG_PM_SLEEP=n
and CONFIG_PM_RUNTIME=y configurations
* easier transition to use struct dev_pm_ops and SIMPLE_DEV_PM_OPS() in
the future
* more consistent code (there are host drivers which are using the correct
CONFIG_PM_SLEEP checks already)
The patch leaves the core libata code and ->port_[suspend,resume] support
in sata_[inic162x,nv,sil24].c alone for now.
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull libata fixes from Tejun Heo:
"Various device specific fixes. Nothing too interesting"
* 'for-3.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata:
ahci: disable NCQ on Samsung pci-e SSDs on macbooks
ata: sata_mv: Cleanup only the initialized ports
sata_sil: apply MOD15WRITE quirk to TOSHIBA MK2561GSYN
ata: enable quirk from jmicron JMB350 for JMB394
ATA: SATA_MV: Add missing Kconfig select statememnt
ata: pata_imx: Check the return value from clk_prepare_enable()
When an error occurs in the port initialization loop, currently the
driver tries to cleanup all the ports. This results in a NULL pointer
dereference if the ports were only partially initialized.
Fix this by updating only the number of initialized ports (either
with failure or successfully), before jumping to the error path
and looping over that number in the cleanup loop.
Cc: Andrew Lunn <andrew@lunn.ch>
Reported-by: Mikael Pettersson <mikpelinux@gmail.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
Make use of devm_phy_optional_get() in order to fix probe failures on
Armada 370, XP and others, when there is no phy driver available.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Some Marvell SoCs have a SATA PHY which can be powered off, in order
to save power. Make use of the generic phy framework to control these
phys.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Tejun Heo <tj@kernel.org>
On Armada 370/XP SoCs, once a disk is removed from a SATA port, then the
re-plug events are not detected by the sata_mv driver. This patch fixes
the issue by updating the PHY speed in the LP_PHY_CTL register (0x58)
according to the SControl speed.
Note that this fix is only applied if the compatible string
"marvell,armada-370-sata" is found in the SATA DT node.
Fixes: 9ae6f740b4 ("arm: mach-mvebu: add support for Armada 370 and Armada XP with DT")
Signed-off-by: Lior Amsalem <alior@marvell.com>
Signed-off-by: Nadav Haklai <nadavh@marvell.com>
Signed-off-by: Simon Guinot <simon.guinot@sequanux.org>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Gregory Clement <gregory.clement@free-electrons.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: stable@vger.kernel.org # v3.6+
Acked-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Tejun Heo <tj@kernel.org>
The sata_mv driver supports the SATA IP found in several Marvell SoCs.
As some new SATA registers have been introduced with the Armada 370/XP
SoCs, a way to identify them is needed.
This patch introduces a new compatible string for the SATA IP found in
Armada 370/XP SoCs.
Signed-off-by: Simon Guinot <simon.guinot@sequanux.org>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Gregory Clement <gregory.clement@free-electrons.com>
Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: Lior Amsalem <alior@marvell.com>
Cc: stable@vger.kernel.org # v3.6+
Acked-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Tejun Heo <tj@kernel.org>
If CONFIG_HAVE_CLK is not selected, then all the clk API turn out
into no-ops. In other words, there's no need to have the ifdefs.
The only side-effect of this patch is the extra tiny kmalloc,
but that's not enough reason to have such ugly ifdefs all around
the code.
tj: Slightly massaged comment as per Andrew Lunn.
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Tejun Heo <tj@kernel.org>
Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
These forward declarations are no longer needed, and are probably
historical left-over.
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
CONFIG_HOTPLUG is going away as an option. As a result, the __dev*
markings need to be removed.
This change removes the use of __devinit, __devexit_p, __devinitdata,
and __devexit from these drivers.
Based on patches originally written by Bill Pemberton, but redone by me
in order to handle some of the coding style issues better, by hand.
Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Viresh Kumar <viresh.linux@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Dove can be configured without PCI. We then get a number of warnings:
warning: 'msi' defined but not used
warning: 'mv5_sht' defined but not used
warning: 'mv_dump_pci_cfg' defined but not used.
Move around variables and add #ifdef as necassary to fix the warnings.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Add support for instantiating this driver from device tree, and add
the necassary DT information to the kirkwood.dtsi file.
This is based on previous work by Michael Walle and Jason Cooper.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Josh Coombs <josh.coombs@gmail.com>
The Orion kirkwood chips have a gatable clock per SATA channel. Add
code to get and enable this clk if it exists.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Jamie Lentin <jm@lentin.co.uk>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Gcc version 4.6.2-12 complains that if we can't find the "nr-ports"
property in of_property_read_u32_array() then "n_ports" is used
uninitialized. Let's set it to zero in that case.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Use an getter function in plat-orion/addr-map.c to get the address map
structure, rather than pass it to drivers in the platform_data
structures. When the drivers are built for none orion platforms, a
dummy function is provided instead which returns NULL.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Michael Walle <michael@walle.cc>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
The driver uses dev_get_drvdata() to get to the driver data for the
platform and PCI devices, while the corresponding wrappers exists for
them -- in one case it even declares an otherwise unneeded variable
to do that. Switch to using the {platform|pci}_get_drvdata() instead.
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
mv_platfrom_probe() forgets to call clk_disable() and clk_put() iff
ata_host_activate() fails...
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Use a single mechanism to show driver version.
Reduces text a tiny bit too.
Remove uses of static int printed_version
Add and use ata_print_version(const struct device *, const char *ver)
and ata_print_version_once.
$ size drivers/ata/built-in.*
text data bss dec hex filename
544969 73893 116584 735446 b38d6 drivers/ata/built-in.allyesconfig.ata.o
543870 73893 116592 734355 b34ad drivers/ata/built-in.allyesconfig.print_once.o
141328 14689 4220 160237 271ed drivers/ata/built-in.defconfig.ata.o
141212 14689 4220 160121 27179 drivers/ata/built-in.defconfig.print_once.o
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
Saves a bit of text as the call takes fewer args.
Coalesce a few formats.
Convert a few bare printks to pr_cont.
$ size drivers/ata/built-in.o*
text data bss dec hex filename
558429 73893 117864 750186 b726a drivers/ata/built-in.o.allyesconfig.new
559574 73893 117888 751355 b76fb drivers/ata/built-in.o.allyesconfig.old
149567 14689 4220 168476 2921c drivers/ata/built-in.o.defconfig.new
149851 14689 4220 168760 29338 drivers/ata/built-in.o.defconfig.old
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
All checks of ATA_FLAG_NO_LEGACY have been removed by the commits
c791c30670 ([libata] minor PCI IDE probe
fixes and cleanups) and f0d36efdc6 (libata:
update libata core layer to use devres), so I think it's time to finally
get rid of this flag...
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Commit 0d5ff56677 (libata: convert to iomap)
removed all checks of ATA_FLAG_MMIO but neglected to remove the flag itself.
Do it now, at last...
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Currently, sata_fsl, mv and nv call ata_qc_complete() multiple times
from their interrupt handlers to indicate completion of NCQ commands.
This limits the visibility the libata core layer has into how commands
are being executed and completed, which is necessary to support IRQ
expecting in generic way. libata already has an interface to complete
multiple commands at once - ata_qc_complete_multiple() which ahci and
sata_sil24 already use.
This patch updates the three drivers to use ata_qc_complete_multiple()
too and updates comments on ata_qc_complete[_multiple]() regarding
their usages with NCQ completions. This change not only provides
better visibility into command execution to the core layer but also
simplifies low level drivers.
* sata_fsl: It already builds done_mask. Conversion is straight
forward.
* sata_mv: mv_process_crpb_response() no longer checks for illegal
completions, it just returns whether the tag is completed or not.
mv_process_crpb_entries() builds done_mask from it and passes it to
ata_qc_complete_multiple() which will check for illegal completions.
* sata_nv adma: Similar to sata_mv. nv_adma_check_cpb() now just
returns the tag status and nv_adma_interrupt() builds done_mask from
it and passes it to ata_qc_complete_multiple().
* sata_nv swncq: It already builds done_mask. Drop unnecessary
illegal transition checks and call ata_qc_complete_multiple().
In the long run, it might be a good idea to make ata_qc_complete()
whine if called when multiple NCQ commands are in flight.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ashish Kalra <ashish.kalra@freescale.com>
Cc: Saeed Bishara <saeed@marvell.com>
Cc: Mark Lord <liml@rtr.ca>
Cc: Robert Hancock <hancockr@shaw.ca>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Keep track of the link on the which the current request is in progress.
It allows support of links behind port multiplier.
Not all libata-sff is PMP compliant. Code for native BMDMA controller
does not take in accound PMP.
Tested on Marvell 7042 and Sil7526.
Signed-off-by: Gwendal Grignou <gwendal@google.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Fix DSM/TRIM commands in sata_mv (v2).
These need to be issued using old-school "BM DMA",
rather than via the EDMA host queue.
Since the chips don't have proper BM DMA status,
we need to be more careful with setting the ATA_DMA_INTR bit,
since DSM/TRIM often has a long delay between "DMA complete"
and "command complete".
GEN_I chips don't have BM DMA, so no TRIM for them.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Cc: stable@kernel.org
Make the following changes to prepare for NCQ command completion
update. Changes made by this patch don't cause any functional
difference.
* sata_fsl_host_intr(): rename the local variable qc_active to
done_mask as that's what it is.
* mv_process_crpb_response(): restructure if clause for easier update.
* nv_adma_interrupt(): drop unnecessary error variable.
* nv_swncq_sdbfis(): drop unnecessary nr_done and return 0 on success.
Typo fix.
* nv_swncq_dmafis(): drop unused return value and return void.
* nv_swncq_host_interrupt(): drop unnecessary return value handling.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ashish Kalra <ashish.kalra@freescale.com>
Cc: Saeed Bishara <saeed@marvell.com>
Cc: Mark Lord <liml@rtr.ca>
Cc: Robert Hancock <hancockr@shaw.ca>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Separate out BMDMA irq handler from SFF irq handler. The misnamed
host_intr() functions are renamed to ata_sff_port_intr() and
ata_bmdma_port_intr(). Common parts are factored into
__ata_sff_port_intr() and __ata_sff_interrupt() and used by sff and
bmdma interrupt routines.
All BMDMA drivers now use ata_bmdma_interrupt() or
ata_bmdma_port_intr() while all non-BMDMA SFF ones use
ata_sff_interrupt() or ata_sff_port_intr().
For now, ata_pci_sff_init_one() uses ata_bmdma_interrupt() as it's
used by both SFF and BMDMA drivers.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Now that BMDMA EH ops are separated out from SFF ops, mv5_ops doesn't
have to explicitly reset ->error_handler() and ->post_internal_cmd().
Drop them.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Separate out ata_bmdma_qc_issue() from ata_sff_qc_issue() such that
ata_sff_qc_issue() only deals with non-BMDMA SFF protocols (PIO and
nodata) while ata_bmdma_qc_issue() deals with the BMDMA protocols and
uses ata_sff_qc_issue() for non-DMA commands. All the users are
updated accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
port_task is tightly bound to the standard SFF PIO HSM implementation.
Using it for any other purpose would be error-prone and there's no
such user and if some drivers need such feature, it would be much
better off using its own. Move it inside CONFIG_ATA_SFF and rename it
to sff_pio_task.
The only function which is exposed to the core layer is
ata_sff_flush_pio_task() which is renamed from ata_port_flush_task()
and now also takes care of resetting hsm_task_state to HSM_ST_IDLE,
which is possible as it's now specific to PIO HSM.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
When BMDMA initialization failed or BMDMA was not available for
whatever reason, bmdma_addr was left at zero and used as an indication
that BMDMA shouldn't be used. This leads to the following problems.
p1. For BMDMA drivers which don't use traditional BMDMA register,
ata_bmdma_mode_filter() incorrectly inhibits DMA modes. Those
drivers either have to inherit from ata_sff_port_ops or clear
->mode_filter explicitly.
p2. non-BMDMA drivers call into BMDMA PRD table allocation. It
doesn't actually allocate PRD table if bmdma_addr is not
initialized but is still confusing.
p3. For BMDMA drivers which don't use traditional BMDMA register, some
methods might not be invoked as expected (e.g. bmdma_stop from
ata_sff_post_internal_cmd()).
p4. SFF drivers w/ custom DMA interface implement noop BMDMA ops
worrying libata core might call into one of them.
These problems are caused by the muddy line between SFF and BMDMA and
the assumption that all BMDMA controllers initialize bmdma_addr.
This patch fixes p1 and p2 by removing the bmdma_addr assumption and
moving prd allocation to BMDMA port start. Later patches will fix the
remaining issues.
This patch improves BMDMA initialization such that
* When BMDMA register initialization fails, falls back to PIO instead
of failing. ata_pci_bmdma_init() never fails now.
* When ata_pci_bmdma_init() falls back to PIO, it clears
ap->mwdma_mask and udma_mask instead of depending on
ata_bmdma_mode_filter(). This makes ata_bmdma_mode_filter()
unnecessary thus resolving p1.
* ata_port_start() which actually is BMDMA specific is moved to
ata_bmdma_port_start(). ata_port_start() and ata_sff_port_start()
are killed.
* ata_sff_port_start32() is moved and renamed to
ata_bmdma_port_start32().
Drivers which no longer call into PRD table allocation are...
pdc_adma, sata_inic162x, sata_qstor, sata_sx4, pata_cmd640 and all
drivers which inherit from ata_sff_port_ops.
pata_icside sets ->port_start to ATA_OP_NULL as it doesn't need PRD
but is a BMDMA controller and doesn't have custom port_start like
other such controllers.
Note that with the previous patch which makes all and only BMDMA
drivers inherit from ata_bmdma_port_ops, this change doesn't break
drivers which need PRD table.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
1. pata_cmd640 is PIO only. Inherit from sff.
2. pata_macio is BMDMA. Inherit from bmdma and drop explicit
bmdma_mode_filter() setting.
3. In sata_mv, unlike mv5, mv6 is BMDMA. Inherit from bmdma and
don't clear ->post_internal_cmd().
4. bf54x and icside are quasi-BMDMA controllers which don't use the
standard BMDMA registers so they don't initialize bmdma_addr and
inherit from sff to avoid the default mode_filter which disables
DMA modes if bmdma_addr is not initialized.
For 2 and 3, this patch makes the drivers explicitly specify
->mode_filter to ATA_OP_NULL while inheriting from ata_bmdma_port_ops.
These will be removed by the next patch.
This patch makes all and only BMDMA drivers inherit from
ata_bmdma_port_ops to ease further SFF/BMDMA separation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Jia-Ju Bai