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path: root/drivers/dma/amba-pl08x.c
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* DMA: PL08x: fix channel pausing to timeout rather than lockupRussell King - ARM Linux2011-01-311-6/+15
| | | | | | | | | | | | | If a transfer is initiated from memory to a peripheral, then data is fetched and the channel is marked busy. This busy status persists until the HALT bit is set and the queued data has been transfered to the peripheral. Waiting indefinitely after setting the HALT bit results in system lockups. Timeout this operation, and print an error when this happens. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* DMA: PL08x: fix infinite wait when terminating transfersRussell King - ARM Linux2011-01-311-14/+18
| | | | | | | | | | | | | | | | | | If we try to pause a channel when terminating a transfer, we could end up spinning for it to become inactive indefinitely, and can result in an uninterruptible wait requiring a reset to recover from. Terminating a transfer is supposed to take effect immediately, but may result in data loss. To make this clear, rename the function to pl08x_terminate_phy_chan(). Also, make sure it is always consistently called - with the spinlock held and IRQs disabled, and ensure that the TC and ERR interrupt status is always cleared. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: cleanup commentsRussell King - ARM Linux2011-01-171-94/+52Star
| | | | | | | | | Cleanup the formatting of comments, remove some which don't make sense anymore. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> [fix conflict with 96a608a4] Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: prevent dma_set_runtime_config() reconfiguring memcpy channelsRussell King - ARM Linux2011-01-051-0/+3
| | | | | | | | | | Prevent dma_set_runtime_config() being used to alter the configuration supplied by the platform for memcpy channel configuration. No one should be trying to change this configuration. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: allow dma_set_runtime_config() to return errorsRussell King - ARM Linux2011-01-051-10/+13
| | | | | | | | | | | | | | There are cases in dma_set_runtime_config() where we fail to perform the requested action - and we just issue a KERN_ERR message in that case. We have the facility to return an error to the caller, so that is what we should do. When we encounter an error due to invalid parameters, we should not modify driver state. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: fix locking between prepare function and submit functionRussell King - ARM Linux2011-01-051-19/+9Star
| | | | | | | | | | | | | | | | | | | The PL08x driver holds on to the channel lock with interrupts disabled between the prepare and the subsequent submit API functions. This means that the locking state when the prepare function returns is dependent on whether it suceeeds or not. It did this to ensure that the physical channel wasn't released, and as it used to add the descriptor onto the pending list at prepare time rather than submit time. Now that we have reorganized the code to remove those reasons, we can now safely release the spinlock at the end of preparation and reacquire it in our submit function. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: introduce 'phychan_hold' to hold on to physical channelsRussell King - ARM Linux2011-01-051-0/+11
| | | | | | | | | | | | | | | Introduce 'phychan_hold' to hold on to physical DMA channels while we're preparing a new descriptor for it. This will be incremented when we allocate a physical channel and set the MUX registers during the preparation of the TXD, and will only be decremented when the TXD is submitted. This prevents the physical channel being given up before the new TXD is placed on the queue. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: put txd's on the pending list in pl08x_tx_submit()Russell King - ARM Linux2011-01-051-14/+32
| | | | | | | | | | | Don't place TXDs on the pending list when they're prepared - place them on the list when they're ready to be submitted. Also, only place memcpy requests in the wait state when they're submitted and don't have a physical channel associated. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: rename 'desc_list' as 'pend_list'Russell King - ARM Linux2011-01-051-10/+10
| | | | | | | | | | This 'desc_list' is actually a list of pending descriptors, so name it after its function (pending list) rather than what it contains (descriptors). Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: implement unmapping of memcpy buffersRussell King - ARM Linux2011-01-051-13/+39
| | | | | | | | | | The DMA engine API requires DMA engine implementations to unmap buffers passed into the non-slave DMA methods unless the relevant completion flag is set. We aren't doing this, so implement this facility. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: store prep_* flags in async_tx structureRussell King - ARM Linux2011-01-051-3/+5
| | | | | | | | | | Like other DMA engine drivers do, store the passed flags into the async_tx structure, so they can be checked when the operation completes. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: shrink srcbus/dstbus in txd structureRussell King - ARM Linux2011-01-051-10/+10
| | | | | | | | We only need to store the dma address. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: don't manipulate txd->srcbus or txd->dstbus during LLI fillRussell King - ARM Linux2011-01-051-76/+83
| | | | | | | | | | Don't alter any txd->srcbus or txd->dstbus values while building the LLI list. This allows us to see the original dma_addr_t values passed in via the prep_memcpy() method. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: fix fill_bytes calculationRussell King - ARM Linux2011-01-051-16/+10Star
| | | | | | | | | | | | | | | | The number of bytes we want to fill into any LLI is the minimum of: - number of bytes remaining in the transfer - number of bytes we can transfer in a single LLI - number of bytes we can transfer without overflowing the source boundary - number of bytes we can transfer without overflowing the destination boundary The minimum of the first two is already calculated (target_len). We limit the boundary calculations to this number of bytes, which will then give us the number of bytes we can place into this LLI. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: use min() to calculate target_lenRussell King - ARM Linux2011-01-051-3/+1Star
| | | | | | Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: ensure pl08x_pre_boundary() works for any value of addrRussell King - ARM Linux2011-01-051-9/+5Star
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | pl08x_pre_boundary() was unsafe with addresses towards the top of memory space: boundary = ((addr >> PL08X_BOUNDARY_SHIFT) + 1) << PL08X_BOUNDARY_SHIFT; This can overflow a 32-bit number, producing zero. When it does: if (boundary < addr + len) return boundary - addr; else return len; results in (boundary - addr) returning either a large positive value. Also if addr + len overflows, this calculation also fails. We can fix this trivially as the only thing we're actually interested in is the value of the least significant PL08X_BOUNDARY_SHIFT bits: boundary_len = PL08X_BOUNDARY_SIZE - (addr & (PL08X_BOUNDARY_SIZE - 1)); gives us the number of bytes before 'addr' becomes a multiple of PL08X_BOUNDARY_SIZE. We can then just take the min() of the two calculated lengths. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: make pl08x_fill_lli_for_desc() return voidRussell King - ARM Linux2011-01-051-18/+12Star
| | | | | | | | | | | | We don't need pl08x_fill_lli_for_desc() to return num_llis + 1 as we know that's what it always does. We can just pass in num_llis and use post-increment in the caller. This makes the code slightly easier to read. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: move callback outside spinlock'd regionRussell King - ARM Linux2011-01-051-14/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Calling the callback handler with spinlocks in the tasklet held leads to deadlock when dmaengine functions are called: BUG: spinlock lockup on CPU#0, sh/417, c1870a08 Backtrace: ... [<c017b408>] (do_raw_spin_lock+0x0/0x154) from [<c02c4b98>] (_raw_spin_lock_irqsave+0x54/0x60) [<c02c4b44>] (_raw_spin_lock_irqsave+0x0/0x60) from [<c01f5828>] (pl08x_prep_channel_resources+0x718/0x8b4) [<c01f5110>] (pl08x_prep_channel_resources+0x0/0x8b4) from [<c01f5bb4>] (pl08x_prep_slave_sg+0x120/0x19c) [<c01f5a94>] (pl08x_prep_slave_sg+0x0/0x19c) from [<c01be7a0>] (pl011_dma_tx_refill+0x164/0x224) [<c01be63c>] (pl011_dma_tx_refill+0x0/0x224) from [<c01bf1c8>] (pl011_dma_tx_callback+0x7c/0xc4) [<c01bf14c>] (pl011_dma_tx_callback+0x0/0xc4) from [<c01f4d34>] (pl08x_tasklet+0x60/0x368) [<c01f4cd4>] (pl08x_tasklet+0x0/0x368) from [<c004d978>] (tasklet_action+0xa0/0x100) Dan quoted the documentation: > 2/ Completion callback routines cannot submit new operations.  This >    results in recursion in the synchronous case and spin_locks being >    acquired twice in the asynchronous case. but then followed up to say: > I should clarify, this is the async_memcpy() api requirement which is > not used outside of md/raid5. DMA drivers can and do allow new > submissions from callbacks, and the ones that do so properly move the > callback outside of the driver lock. So let's fix it by moving the callback out of the spinlocked region. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: allow AHB master port selection to be configuredRussell King - ARM Linux2011-01-051-34/+43
| | | | | | | | | | | Platforms need to be able to control which AHB master interface is used, as each AHB master interface may be asymetric. Allow the interfaces used for fetching LLIs, memory, and each peripheral to be configured individually. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: move AHB master port selection into prep_* functionsRussell King - ARM Linux2011-01-051-24/+23Star
| | | | | | | | | | | As we initialize the default cctl value in the prep_* functions along with the increment settings, we don't need to repeat the selection of the AHB ports each time we create a LLI entry. Do this in the prep_* functions once per transfer. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: move cctl increment and protection setup to prep_slave_sgRussell King - ARM Linux2011-01-051-7/+8
| | | | | | | | | | We don't need to initialize the cctl increment and protection values in the runtime_config method - we have all the inforamtion to setup these values in prep_slave_sg(). Move their initialization there. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: move default cctl into txd structureRussell King - ARM Linux2011-01-051-15/+6Star
| | | | | | | | | Rather than modifying platform data while preparing a transfer, copy the cctl value into the txd structure and modify the value there. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: assign ccfg DMA request signal in prep_phy_channel()Russell King - ARM Linux2011-01-051-11/+9Star
| | | | | | | | | | | | There is no need to wait until we start processing a tx descriptor before setting up the DMA request selection in the ccfg register. We know which channel and request will be used in prep_phy_channel(), so setup the ccfg request selection at txd creation time in prep_phy_channel(). Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: move ccfg into txd structureRussell King - ARM Linux2011-01-051-16/+12Star
| | | | | | | | | | | | | | | | | | The ccfg register is used to configure the channel parameters - the type and direction of transfer, the flow control signal and IRQ mask enables. The type and direction of transfer is known in the relevent prep_* function where a txd is created. The IRQ mask enables are always set, and the flow control signals are always set when we start processing a txd according to phychan->signal. If we store the ccfg value in the txd structure, we can avoid modifying platform data - and even having it in platform data at all. So, remove it from platform data too. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: avoid duplicating registers in txd and phychan structuresRussell King - ARM Linux2011-01-051-38/+19Star
| | | | | | | | | | | | | | | | As we now have all the code accessing the phychan {csrc,cdst,clli,cctl, ccfg} members in one function, there's no point storing the data into the struct. Get rid of the struct members. Re-order the register dump in the dev_dbg() to reflect the order we write the registers to the DMA device. The txd {csrc,cdst,clli,cctl} values are duplicates of the lli[0] values, so there's no point duplicating these either. Program the DMAC registers directly from the lli[0] values. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: combine functions to start DMA into one functionRussell King - ARM Linux2011-01-051-60/+38Star
| | | | | | | | | | There is no need for pl08x_config_phychan_for_txd(), pl08x_set_cregs() and pl08x_enable_phy_chan() to be separate - they are always called in sequence. Combine them into one function. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: clean up LLI lookupRussell King - ARM Linux2011-01-051-17/+20
| | | | | | | | | | | | | As the LLI list is an array, we can use maths to locate which LLI index we're currently at, and then sum up the remaining LLI entries until we reach the end of the list. This makes the code much easier to read, and much less susceptible to falling off the end of the array. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: rename lli.next to lli.lliRussell King - ARM Linux2011-01-051-6/+6
| | | | | | | | | The LLI pointer in the documentation is placed into the LLI register, so name it LLI rather than 'next'. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: use 'u32' for LLI structure members, not dma_addr_tRussell King - ARM Linux2011-01-051-4/+5
| | | | | | | | | Use 'u32' for the LLI structure members, which are defined by hardware to be 32-bit. dma_addr_t is much more vague about its actual size. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: use 'size_t' for lengthsRussell King - ARM Linux2011-01-051-23/+17Star
| | | | | | | | | | | Use size_t for variables denoting lengths throughout, and use the 'z' qualifier for printing the value. For safety, add a BUG_ON() in pl08x_fill_lli_for_desc() to catch the remainder potentially becoming negative. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: don't try to use llis_bus as a pointerRussell King - ARM Linux2011-01-051-6/+3Star
| | | | | | | | | | | llis_bus is the DMA address of the LLI array. Casting it to be a pointer just to be able to use pointer arithmetic on it is not nice. We can trivially deal with the places where we do arithmetic on it, and it's actually cleaner this way. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: don't assume that the LLI pointer has the bus bit clearRussell King - ARM Linux2011-01-051-1/+1
| | | | | | | | | | We only want use the address of the LLI pointer when locating the corresponding structure in memory, so clear the master bus selection bit. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: ensure loops use cpu_relax()Russell King - ARM Linux2011-01-051-3/+3
| | | | | | | | | Tight loops should use cpu_relax() to allow CPUs to reduce power consumption while waiting for events. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: consolidate physical channel release codeRussell King - ARM Linux2011-01-051-14/+14
| | | | | | | | Consolidate duplicated channel release code into release_phy_channel() Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: consolidate common txd initializationRussell King - ARM Linux2011-01-051-13/+14
| | | | | | | | Consolidate code which allocates and initializes txds. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: avoid 'void *' struct fields when we can type them properlyRussell King - ARM Linux2011-01-051-8/+8
| | | | | | | | | | Avoid using 'void *' struct fields when the structs are not defined in linux/amba/pl08x.h - instead, forward declare the struct names, and use these instead. This ensures we have proper typechecking. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: constify vendor data pointersRussell King - ARM Linux2011-01-051-2/+2
| | | | | | | | We should never modify the vendor data structure so make it const. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: remove circular buffer supportRussell King - ARM Linux2011-01-051-51/+20Star
| | | | | | | | | | The driver already won't initialize a channel with a circular buffer; the check in pl08x_prep_channel_resources() sees to that. Remove circular buffer support for the time being. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: remove unnecessary NULL and BUG checksRussell King - ARM Linux2011-01-051-21/+0Star
| | | | | | | | | | | | | | | | | | | | The tasklet always is initialized with a non-NULL data argument. It is not possible for it to be called with a NULL data argument (unless something is very wrong in the tasklet code - in which case lots of stuff will break). Therefore, as plchan can never be NULL, remove this unnecessary BUG check. In pl08x_tasklet(), we've already dereferenced plchan->at, so it can't be NULL here. Remove this unnecessary BUG check. pl08x_fill_llis_for_desc() and pl08x_free_txd() are always called with a non-NULL txd argument - either as a consequence of the code paths or as a result of other checks already in place. We don't need to repeat the non-NULL check in these functions. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: remove unnecessary includesRussell King - ARM Linux2011-01-051-6/+1Star
| | | | | | | | | | | | We don't need to include linux/pci.h as we aren't a PCI driver. We aren't doing any processor specific functions, so asm/processor.h is not required. asm/cacheflush.h shouldn't be used, we have the DMA API for this. DMA interfaces aren't required as we're only implementing the dmaengine API and not a platform-private DMA API. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: prefix hex numbers with 0xRussell King - ARM Linux2011-01-051-9/+9
| | | | | | | | | A driver which emits both decimal and hex numbers in its printk creates confusion as to what is what. Prefix hex numbers with 0x. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: improve the announcement printkRussell King - ARM Linux2011-01-051-7/+4Star
| | | | | | | | | | | Include the revision number of the PL08x primecell in the boot-time printk to allow proper identification of the peripheral. Reformat the announcement printk format reflect what we do for other primecell drivers - generally "PLXXX revX at 0xNNNNNNNN irq X". Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: add comment explaining the flow control methodsRussell King - ARM Linux2011-01-051-1/+17
| | | | | | | | | | | Explain the two flow control methods which the PL08x implements, along with the problem which peripheral flow control presents. This helps people understand why we are unable to use these DMA controllers with (eg) the MMCI. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: fix sparse warningsRussell King - ARM Linux2011-01-051-5/+5
| | | | | | | | | | | | drivers/dma/amba-pl08x.c:1895:40: warning: Unknown escape '%' drivers/dma/amba-pl08x.c:1903:40: warning: Unknown escape '%' drivers/dma/amba-pl08x.c:513:6: warning: symbol 'pl08x_choose_master_bus' was not declared. Should it be static? drivers/dma/amba-pl08x.c:604:5: warning: symbol 'pl08x_fill_llis_for_desc' was not declared. Should it be static? drivers/dma/amba-pl08x.c:1442:32: warning: symbol 'pl08x_prep_slave_sg' was not declared. Should it be static? Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: fix deadlock in terminate_allRussell King - ARM Linux2011-01-051-2/+0Star
| | | | | | | | | | | | | | | | | | | | | Trying to disable a tasklet while holding a spinlock which the tasklet will take is a recipe for deadlock - tasklet_disable() will wait for the tasklet to finish running, which it will never do. In any case, there is not a corresponding tasklet_enable(), so once the tasklet is disabled, it will never run again until reboot. It's safe to just remove the tasklet_disable() as we remove all current and pending descriptors before releasing this spinlock. This means that the tasklet will find no remaining work if it subsequently runs. The only remaining issue is that the callback for an already submitted txd may be in progress, or even called after terminate_all() returns. There's not much that can be done about that as waiting for the callback to complete before returning will also lead to deadlocks. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: fix missed spin-unlock in pl08x_issue_pending()Russell King - ARM Linux2011-01-051-8/+4Star
| | | | | | | | | | | | pl08x_issue_pending() returns with the spinlock locked and interrupts disabled if the channel is waiting for a physical DMA to become free. This is wrong - especially as pl08x_issue_pending() is an API function as it leads to deadlocks. Fix it to always return with the spinlock unlocked. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: fix a leak when preparing TXDsRussell King - ARM Linux2011-01-051-2/+3
| | | | | | | | | | | If we fail to allocate the LLI, the prep_* function will return NULL. However, the TXD we allocated will not be placed on any list, nor will it be freed - we'll just drop all references to it. Make sure we free it rather than leaking TXDs. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: fix locking in taskletRussell King - ARM Linux2011-01-051-2/+3
| | | | | | | | | | | | Tasklets are run from an interruptible context. The slave DMA functions can be called from within IRQ handlers. Taking the spinlock without disabling interrupts allows an interrupt handler to run, which may try to take the spinlock again, resulting in deadlock. Fix this by using the irqsave spinlocks. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: fix atomic_t usage and tx_submit() return value rangeRussell King - ARM Linux2011-01-051-9/+9
| | | | | | | | | | | | | | | | The last_issued variable uses an atomic type, which is only incremented inside a protected region, and then read. Everywhere else only reads the value, so it isn't using atomic_t correctly, and it doesn't even need to. Moreover, the DMA engine code provides us with a variable for this already - chan.cookie. Use chan.cookie instead. Also, avoid negative dma_cookie_t values - negative returns from tx_submit() mean failure, yet in reality we always succeed. Restart from cookie 1, just like other DMA engine drivers do. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* ARM: PL08x: fix array overflow in dma_set_runtime_config()Russell King - ARM Linux2011-01-051-7/+6Star
| | | | | | | | | | | | | If maxburst was passed in as zero, we would overflow the burst_sizes[] array. Fix this by checking for this condition, and defaulting to single transfer 'bursts'. Improve the readability of the loop using a for() loop rather than a while() loop with the iterator initialized far from the loop. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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