forked from Minki/linux
622882455a
The buffer descriptors for the ATA BestComm task are larger than the current definition for bcom_bd. This causes problems because the various bcom_... functions dereference the buffer descriptor pointer by using the array operator which doesn't work when the buffer descriptors are a different size. This patch adds the bcom_get_bd() function which uses the value in bcom_task.bd_size to calculate the offset into the BD table. This patch also changes the definition of bcom_bd to specify a data size of 0 instead of 1 so that it will never work if anyone attempts to dereference the bd list as an array (as opposed to something that might work even though it is wrong). Finally, this patch moves the definition of bcom_bd up in the file to eliminate a forward declaration. Based on patch originally written by Tim Yamin. Signed-off-by: Tim Yamin <plasm@roo.me.uk> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
214 lines
5.6 KiB
C
214 lines
5.6 KiB
C
/*
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* Public header for the MPC52xx processor BestComm driver
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*
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*
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* Copyright (C) 2006 Sylvain Munaut <tnt@246tNt.com>
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* Copyright (C) 2005 Varma Electronics Oy,
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* ( by Andrey Volkov <avolkov@varma-el.com> )
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* Copyright (C) 2003-2004 MontaVista, Software, Inc.
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* ( by Dale Farnsworth <dfarnsworth@mvista.com> )
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*
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* This file is licensed under the terms of the GNU General Public License
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* version 2. This program is licensed "as is" without any warranty of any
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* kind, whether express or implied.
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*/
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#ifndef __BESTCOMM_H__
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#define __BESTCOMM_H__
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/**
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* struct bcom_bd - Structure describing a generic BestComm buffer descriptor
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* @status: The current status of this buffer. Exact meaning depends on the
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* task type
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* @data: An array of u32 extra data. Size of array is task dependant.
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*
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* Note: Don't dereference a bcom_bd pointer as an array. The size of the
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* bcom_bd is variable. Use bcom_get_bd() instead.
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*/
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struct bcom_bd {
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u32 status;
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u32 data[0]; /* variable payload size */
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};
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/* ======================================================================== */
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/* Generic task management */
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/* ======================================================================== */
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/**
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* struct bcom_task - Structure describing a loaded BestComm task
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*
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* This structure is never built by the driver it self. It's built and
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* filled the intermediate layer of the BestComm API, the task dependent
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* support code.
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*
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* Most likely you don't need to poke around inside this structure. The
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* fields are exposed in the header just for the sake of inline functions
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*/
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struct bcom_task {
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unsigned int tasknum;
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unsigned int flags;
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int irq;
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struct bcom_bd *bd;
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phys_addr_t bd_pa;
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void **cookie;
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unsigned short index;
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unsigned short outdex;
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unsigned int num_bd;
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unsigned int bd_size;
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void* priv;
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};
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#define BCOM_FLAGS_NONE 0x00000000ul
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#define BCOM_FLAGS_ENABLE_TASK (1ul << 0)
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/**
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* bcom_enable - Enable a BestComm task
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* @tsk: The BestComm task structure
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*
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* This function makes sure the given task is enabled and can be run
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* by the BestComm engine as needed
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*/
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extern void bcom_enable(struct bcom_task *tsk);
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/**
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* bcom_disable - Disable a BestComm task
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* @tsk: The BestComm task structure
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*
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* This function disable a given task, making sure it's not executed
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* by the BestComm engine.
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*/
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extern void bcom_disable(struct bcom_task *tsk);
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/**
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* bcom_get_task_irq - Returns the irq number of a BestComm task
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* @tsk: The BestComm task structure
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*/
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static inline int
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bcom_get_task_irq(struct bcom_task *tsk) {
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return tsk->irq;
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}
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/* ======================================================================== */
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/* BD based tasks helpers */
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/* ======================================================================== */
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#define BCOM_BD_READY 0x40000000ul
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/** _bcom_next_index - Get next input index.
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* @tsk: pointer to task structure
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*
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* Support function; Device drivers should not call this
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*/
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static inline int
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_bcom_next_index(struct bcom_task *tsk)
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{
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return ((tsk->index + 1) == tsk->num_bd) ? 0 : tsk->index + 1;
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}
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/** _bcom_next_outdex - Get next output index.
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* @tsk: pointer to task structure
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*
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* Support function; Device drivers should not call this
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*/
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static inline int
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_bcom_next_outdex(struct bcom_task *tsk)
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{
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return ((tsk->outdex + 1) == tsk->num_bd) ? 0 : tsk->outdex + 1;
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}
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/**
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* bcom_queue_empty - Checks if a BestComm task BD queue is empty
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* @tsk: The BestComm task structure
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*/
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static inline int
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bcom_queue_empty(struct bcom_task *tsk)
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{
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return tsk->index == tsk->outdex;
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}
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/**
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* bcom_queue_full - Checks if a BestComm task BD queue is full
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* @tsk: The BestComm task structure
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*/
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static inline int
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bcom_queue_full(struct bcom_task *tsk)
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{
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return tsk->outdex == _bcom_next_index(tsk);
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}
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/**
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* bcom_get_bd - Get a BD from the queue
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* @tsk: The BestComm task structure
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* index: Index of the BD to fetch
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*/
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static inline struct bcom_bd
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*bcom_get_bd(struct bcom_task *tsk, unsigned int index)
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{
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/* A cast to (void*) so the address can be incremented by the
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* real size instead of by sizeof(struct bcom_bd) */
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return ((void *)tsk->bd) + (index * tsk->bd_size);
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}
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/**
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* bcom_buffer_done - Checks if a BestComm
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* @tsk: The BestComm task structure
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*/
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static inline int
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bcom_buffer_done(struct bcom_task *tsk)
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{
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struct bcom_bd *bd;
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if (bcom_queue_empty(tsk))
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return 0;
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bd = bcom_get_bd(tsk, tsk->outdex);
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return !(bd->status & BCOM_BD_READY);
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}
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/**
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* bcom_prepare_next_buffer - clear status of next available buffer.
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* @tsk: The BestComm task structure
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*
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* Returns pointer to next buffer descriptor
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*/
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static inline struct bcom_bd *
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bcom_prepare_next_buffer(struct bcom_task *tsk)
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{
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struct bcom_bd *bd;
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bd = bcom_get_bd(tsk, tsk->index);
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bd->status = 0; /* cleanup last status */
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return bd;
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}
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static inline void
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bcom_submit_next_buffer(struct bcom_task *tsk, void *cookie)
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{
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struct bcom_bd *bd = bcom_get_bd(tsk, tsk->index);
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tsk->cookie[tsk->index] = cookie;
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mb(); /* ensure the bd is really up-to-date */
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bd->status |= BCOM_BD_READY;
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tsk->index = _bcom_next_index(tsk);
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if (tsk->flags & BCOM_FLAGS_ENABLE_TASK)
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bcom_enable(tsk);
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}
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static inline void *
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bcom_retrieve_buffer(struct bcom_task *tsk, u32 *p_status, struct bcom_bd **p_bd)
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{
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void *cookie = tsk->cookie[tsk->outdex];
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struct bcom_bd *bd = bcom_get_bd(tsk, tsk->outdex);
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if (p_status)
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*p_status = bd->status;
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if (p_bd)
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*p_bd = bd;
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tsk->outdex = _bcom_next_outdex(tsk);
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return cookie;
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}
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#endif /* __BESTCOMM_H__ */
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