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f82c3e62b6
This reverts commit5378bdf6a6. Commit5378bdf6a6("mailbox/pcc: support mailbox management of the shared buffer") attempted to introduce generic helpers for managing the PCC shared memory, but it largely duplicates functionality already provided by the mailbox core and leaves gaps: 1. TX preparation: The mailbox framework already supports this via ->tx_prepare callback for mailbox clients. The patch adds pcc_write_to_buffer() and expects clients to toggle pchan->chan.manage_writes, but no drivers set manage_writes, so pcc_write_to_buffer() has no users. 2. RX handling: Data reception is already delivered through mbox_chan_received_data() and client ->rx_callback. The patch adds an optional pchan->chan.rx_alloc, which again has no users and duplicates the existing path. 3. Completion handling: While adding last_tx_done is directionally useful, the implementation only covers Type 3/4 and fails to handle the absence of a command_complete register, so it is incomplete for other types. Given the duplication and incomplete coverage, revert this change. Any new requirements should be addressed in focused follow-ups rather than bundling multiple behavioral changes together. Fixes:5378bdf6a6("mailbox/pcc: support mailbox management of the shared buffer") Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
50 lines
1.3 KiB
C
50 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* PCC (Platform Communications Channel) methods
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*/
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#ifndef _PCC_H
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#define _PCC_H
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#include <linux/mailbox_controller.h>
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#include <linux/mailbox_client.h>
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struct pcc_mbox_chan {
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struct mbox_chan *mchan;
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u64 shmem_base_addr;
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void __iomem *shmem;
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u64 shmem_size;
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u32 latency;
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u32 max_access_rate;
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u16 min_turnaround_time;
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};
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/* Generic Communications Channel Shared Memory Region */
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#define PCC_SIGNATURE 0x50434300
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/* Generic Communications Channel Command Field */
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#define PCC_CMD_GENERATE_DB_INTR BIT(15)
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/* Generic Communications Channel Status Field */
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#define PCC_STATUS_CMD_COMPLETE BIT(0)
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#define PCC_STATUS_SCI_DOORBELL BIT(1)
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#define PCC_STATUS_ERROR BIT(2)
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#define PCC_STATUS_PLATFORM_NOTIFY BIT(3)
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/* Initiator Responder Communications Channel Flags */
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#define PCC_CMD_COMPLETION_NOTIFY BIT(0)
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#define MAX_PCC_SUBSPACES 256
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#ifdef CONFIG_PCC
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extern struct pcc_mbox_chan *
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pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id);
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extern void pcc_mbox_free_channel(struct pcc_mbox_chan *chan);
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#else
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static inline struct pcc_mbox_chan *
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pcc_mbox_request_channel(struct mbox_client *cl, int subspace_id)
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{
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return ERR_PTR(-ENODEV);
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}
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static inline void pcc_mbox_free_channel(struct pcc_mbox_chan *chan) { }
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#endif
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#endif /* _PCC_H */
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