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by Steven

2 months

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[PATCH 1/2] zram: refuse to use zero sized block device as backing device

by Kairui Song

From: Kairui Song <kasong(a)tencent.com> Setting a zero sized block device as backing device is pointless, and one can easily create a recursive loop by setting the uninitialized ZRAM device itself as its own backing device by (zram0 is uninitialized): echo /dev/zram0 > /sys/block/zram0/backing_dev It's definitely a wrong config, and the module will pin itself, kernel should refuse doing so in the first place. By refusing to use zero sized device we avoided misuse cases including this one above. Fixes: 013bf95a83ec ("zram: add interface to specif backing device") Reported-by: Desheng Wu <deshengwu(a)tencent.com> Signed-off-by: Kairui Song <kasong(a)tencent.com> Cc: stable(a)vger.kernel.org --- drivers/block/zram/zram_drv.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 0ca6d55c9917..dd48df5b97c8 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -614,6 +614,12 @@ static ssize_t backing_dev_store(struct device *dev, } nr_pages = i_size_read(inode) >> PAGE_SHIFT; + /* Refuse to use zero sized device (also prevents self reference) */ + if (!nr_pages) { + err = -EINVAL; + goto out; + } + bitmap_sz = BITS_TO_LONGS(nr_pages) * sizeof(long); bitmap = kvzalloc(bitmap_sz, GFP_KERNEL); if (!bitmap) { -- 2.47.0

2 months

2
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[PATCH v3] btrfs: do proper folio cleanup when run_delalloc_nocow() failed

by Qu Wenruo

[BUG] There are at least two problems when run_delalloc_nocow() hits some error and has to go cleanup routine: - It doesn't clear the folio dirty flags of any successfully ran range This breaks the regular error handling protocol for folio writeback, which should clear the dirty flag of the failed range. This clean up protocol is adapted by both iomap and btrfs (if the error happened at the very beginning of the whole delalloc range). - It can start writeback/unlock folios which is already unlocked This is done by calling extent_clear_unlock_delalloc() with PAGE_START_WRITEBACK or PAGE_UNLOCK flag. This will trigger the VM_BUG_ON() for folio_start_writeback(), which requires the folio to be locked. [CAUSE] The problem of not clearing the folio dirty flag is a common bug, shared between cow_file_range() and run_delalloc_nocow(). We just need to clear the folio dirty flags according to the @cur_offset cursor. For the extent_clear_unlock_delalloc() on unlocked folios, it's because the double error handling, one from cow_file_range() (inside fallback_to_cow()), one from run_delalloc_nocow() itself. [FIX] - Clear folio dirty for range [@start, @cur_offset) Introduce a helper, cleanup_dirty_folios(), which will find and lock the folio in the range, clear the dirty flag and start/end the writeback, with the extra handling for the @locked_folio. - Introduce a helper to record the last failed COW range end This is to trace which range we should skip, to avoid double unlocking. - Skip the failed COW range for the error handling Cc: stable(a)vger.kernel.org Signed-off-by: Qu Wenruo <wqu(a)suse.com> --- Changelog: v3: - Fix the double error handling on the COW range Which can lead to VM_BUG_ON() for extent_clear_unlock_delalloc(), as the folio is already unlocked by the error handling inside cow_file_range(). - Update the commit message to explain the bug better - Add a comment inside the error handling explaining the error patterns v2: - Fix the incorrect @cur_offset assignment to @end The @end is not aligned to sector size, nor @cur_offset should be updated before fallback_to_cow() succeeded. - Add one extra ASSERT() to make sure the range is properly aligned --- fs/btrfs/inode.c | 93 ++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 86 insertions(+), 7 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 9517fb2df649..069599b025a6 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1969,6 +1969,48 @@ static int can_nocow_file_extent(struct btrfs_path *path, return ret < 0 ? ret : can_nocow; } +static void cleanup_dirty_folios(struct btrfs_inode *inode, + struct folio *locked_folio, + u64 start, u64 end, int error) +{ + struct btrfs_fs_info *fs_info = inode->root->fs_info; + struct address_space *mapping = inode->vfs_inode.i_mapping; + pgoff_t start_index = start >> PAGE_SHIFT; + pgoff_t end_index = end >> PAGE_SHIFT; + u32 len; + + ASSERT(end + 1 - start < U32_MAX); + ASSERT(IS_ALIGNED(start, fs_info->sectorsize) && + IS_ALIGNED(end + 1, fs_info->sectorsize)); + len = end + 1 - start; + + /* + * Handle the locked folio first. + * btrfs_folio_clamp_*() helpers can handle range out of the folio case. + */ + btrfs_folio_clamp_clear_dirty(fs_info, locked_folio, start, len); + btrfs_folio_clamp_set_writeback(fs_info, locked_folio, start, len); + btrfs_folio_clamp_clear_writeback(fs_info, locked_folio, start, len); + + for (pgoff_t index = start_index; index <= end_index; index++) { + struct folio *folio; + + /* Already handled at the beginning. */ + if (index == locked_folio->index) + continue; + folio = __filemap_get_folio(mapping, index, FGP_LOCK, GFP_NOFS); + /* Cache already dropped, no need to do any cleanup. */ + if (IS_ERR(folio)) + continue; + btrfs_folio_clamp_clear_dirty(fs_info, folio, start, len); + btrfs_folio_clamp_set_writeback(fs_info, folio, start, len); + btrfs_folio_clamp_clear_writeback(fs_info, folio, start, len); + folio_unlock(folio); + folio_put(folio); + } + mapping_set_error(mapping, error); +} + /* * when nowcow writeback call back. This checks for snapshots or COW copies * of the extents that exist in the file, and COWs the file as required. @@ -1984,6 +2026,11 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode, struct btrfs_root *root = inode->root; struct btrfs_path *path; u64 cow_start = (u64)-1; + /* + * If not 0, represents the inclusive end of the last fallback_to_cow() + * range. Only for error handling. + */ + u64 cow_end = 0; u64 cur_offset = start; int ret; bool check_prev = true; @@ -2144,6 +2191,7 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode, found_key.offset - 1); cow_start = (u64)-1; if (ret) { + cow_end = found_key.offset - 1; btrfs_dec_nocow_writers(nocow_bg); goto error; } @@ -2217,11 +2265,12 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode, cow_start = cur_offset; if (cow_start != (u64)-1) { - cur_offset = end; ret = fallback_to_cow(inode, locked_folio, cow_start, end); cow_start = (u64)-1; - if (ret) + if (ret) { + cow_end = end; goto error; + } } btrfs_free_path(path); @@ -2229,12 +2278,42 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode, error: /* - * If an error happened while a COW region is outstanding, cur_offset - * needs to be reset to cow_start to ensure the COW region is unlocked - * as well. + * There are several error cases: + * + * 1) Failed without falling back to COW + * start cur_start end + * |/////////////| | + * + * For range [start, cur_start) the folios are already unlocked (except + * @locked_folio), EXTENT_DELALLOC already removed. + * Only need to clear the dirty flag as they will never be submitted. + * Ordered extent and extent maps are handled by + * btrfs_mark_ordered_io_finished() inside run_delalloc_range(). + * + * 2) Failed with error from fallback_to_cow() + * start cur_start cow_end end + * |/////////////|-----------| | + * + * For range [start, cur_start) it's the same as case 1). + * But for range [cur_start, cow_end), the folios have dirty flag + * cleared and unlocked, EXTENT_DEALLLOC cleared. + * There may or may not be any ordered extents/extent maps allocated. + * + * We should not call extent_clear_unlock_delalloc() on range [cur_start, + * cow_end), as the folios are already unlocked. + * + * So clear the folio dirty flags for [start, cur_offset) first. */ - if (cow_start != (u64)-1) - cur_offset = cow_start; + if (cur_offset > start) + cleanup_dirty_folios(inode, locked_folio, start, cur_offset - 1, ret); + + /* + * If an error happened while a COW region is outstanding, cur_offset + * needs to be reset to @cow_end + 1 to skip the COW range, as + * cow_file_range() will do the proper cleanup at error. + */ + if (cow_end) + cur_offset = cow_end + 1; /* * We need to lock the extent here because we're clearing DELALLOC and -- 2.47.1

2 months

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[PATCH v2] btrfs: do proper folio cleanup when run_delalloc_nocow() failed

by Qu Wenruo

Just like cow_file_range(), from day 1 btrfs doesn't really clean the dirty flags, if it has an ordered extent created successfully. Per error handling protocol (according to the iomap, and the btrfs handling if it failed at the beginning of the range), we should clear all dirty flags for the involved folios. Or the range of that folio will still be marked dirty, but has no EXTENT_DEALLLOC set inside the io tree. Since the folio range is still dirty, it will still be the target for the next writeback, but since there is no EXTENT_DEALLLOC, no new ordered extent will be created for it. This means the writeback of that folio range will fall back to COW fixup path. However the COW fixup path itself is being re-evaluated as the newly introduced pin_user_pages_*() should prevent us hitting an out-of-band dirty folios, and we're moving to deprecate such COW fixup path. We already have an experimental patch that will make fixup COW path to crash, to verify there is no such out-of-band dirty folios anymore. So here we need to avoid going COW fixup path, by doing proper folio dirty flags cleanup. Unlike the fix in cow_file_range(), which holds the folio and extent lock until error or a fully successfully run, here we have no such luxury as we can fallback to COW, and in that case the extent/folio range will be unlocked by cow_file_range(). So here we introduce a new helper, cleanup_dirty_folios(), to clear the dirty flags for the involved folios. And since the final fallback_to_cow() call can also fail, and we rely on @cur_offset to do the proper cleanup, here we remove the unnecessary and incorrect @cur_offset assignment. Cc: stable(a)vger.kernel.org Signed-off-by: Qu Wenruo <wqu(a)suse.com> --- Changelog: v2: - Fix the incorrect @cur_offset assignment to @end The @end is not aligned to sector size, nor @cur_offset should be updated before fallback_to_cow() succeeded. - Add one extra ASSERT() to make sure the range is properly aligned --- fs/btrfs/inode.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 58 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index e8232ac7917f..92df6dfff2e4 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1969,6 +1969,48 @@ static int can_nocow_file_extent(struct btrfs_path *path, return ret < 0 ? ret : can_nocow; } +static void cleanup_dirty_folios(struct btrfs_inode *inode, + struct folio *locked_folio, + u64 start, u64 end, int error) +{ + struct btrfs_fs_info *fs_info = inode->root->fs_info; + struct address_space *mapping = inode->vfs_inode.i_mapping; + pgoff_t start_index = start >> PAGE_SHIFT; + pgoff_t end_index = end >> PAGE_SHIFT; + u32 len; + + ASSERT(end + 1 - start < U32_MAX); + ASSERT(IS_ALIGNED(start, fs_info->sectorsize) && + IS_ALIGNED(end + 1, fs_info->sectorsize)); + len = end + 1 - start; + + /* + * Handle the locked folio first. + * btrfs_folio_clamp_*() helpers can handle range out of the folio case. + */ + btrfs_folio_clamp_clear_dirty(fs_info, locked_folio, start, len); + btrfs_folio_clamp_set_writeback(fs_info, locked_folio, start, len); + btrfs_folio_clamp_clear_writeback(fs_info, locked_folio, start, len); + + for (pgoff_t index = start_index; index <= end_index; index++) { + struct folio *folio; + + /* Already handled at the beginning. */ + if (index == locked_folio->index) + continue; + folio = __filemap_get_folio(mapping, index, FGP_LOCK, GFP_NOFS); + /* Cache already dropped, no need to do any cleanup. */ + if (IS_ERR(folio)) + continue; + btrfs_folio_clamp_clear_dirty(fs_info, folio, start, len); + btrfs_folio_clamp_set_writeback(fs_info, folio, start, len); + btrfs_folio_clamp_clear_writeback(fs_info, folio, start, len); + folio_unlock(folio); + folio_put(folio); + } + mapping_set_error(mapping, error); +} + /* * when nowcow writeback call back. This checks for snapshots or COW copies * of the extents that exist in the file, and COWs the file as required. @@ -2217,7 +2259,6 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode, cow_start = cur_offset; if (cow_start != (u64)-1) { - cur_offset = end; ret = fallback_to_cow(inode, locked_folio, cow_start, end); cow_start = (u64)-1; if (ret) @@ -2228,6 +2269,22 @@ static noinline int run_delalloc_nocow(struct btrfs_inode *inode, return 0; error: + /* + * We have some range with ordered extent created. + * + * Ordered extents and extent maps will be cleaned up by + * btrfs_mark_ordered_io_finished() later, but we also need to cleanup + * the dirty flags of folios. + * + * Or they can be written back again, but without any EXTENT_DELALLOC flag + * in io tree. + * This will force the writeback to go COW fixup, which is being deprecated. + * + * Also such left-over dirty flags do no follow the error handling protocol. + */ + if (cur_offset > start) + cleanup_dirty_folios(inode, locked_folio, start, cur_offset - 1, ret); + /* * If an error happened while a COW region is outstanding, cur_offset * needs to be reset to cow_start to ensure the COW region is unlocked -- 2.47.1

2 months

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[for-linus][PATCH 1/2] tracing: Fix cmp_entries_dup() to respect sort() comparison rules

by Steven Rostedt

From: Kuan-Wei Chiu <visitorckw(a)gmail.com> The cmp_entries_dup() function used as the comparator for sort() violated the symmetry and transitivity properties required by the sorting algorithm. Specifically, it returned 1 whenever memcmp() was non-zero, which broke the following expectations: * Symmetry: If x < y, then y > x. * Transitivity: If x < y and y < z, then x < z. These violations could lead to incorrect sorting and failure to correctly identify duplicate elements. Fix the issue by directly returning the result of memcmp(), which adheres to the required comparison properties. Cc: stable(a)vger.kernel.org Fixes: 08d43a5fa063 ("tracing: Add lock-free tracing_map") Link: https://lore.kernel.org/20241203202228.1274403-1-visitorckw@gmail.com Signed-off-by: Kuan-Wei Chiu <visitorckw(a)gmail.com> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/tracing_map.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c index 3a56e7c8aa4f..1921ade45be3 100644 --- a/kernel/trace/tracing_map.c +++ b/kernel/trace/tracing_map.c @@ -845,15 +845,11 @@ int tracing_map_init(struct tracing_map *map) static int cmp_entries_dup(const void *A, const void *B) { const struct tracing_map_sort_entry *a, *b; - int ret = 0; a = *(const struct tracing_map_sort_entry **)A; b = *(const struct tracing_map_sort_entry **)B; - if (memcmp(a->key, b->key, a->elt->map->key_size)) - ret = 1; - - return ret; + return memcmp(a->key, b->key, a->elt->map->key_size); } static int cmp_entries_sum(const void *A, const void *B) -- 2.45.2

2 months

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[PATCH v2] ufs: core: add missing post notify for power mode change

by peter.wang＠mediatek.com

From: Peter Wang <peter.wang(a)mediatek.com> When the power mode change is successful but the power mode hasn't actually changed, the post notification was missed. Similar to the approach with hibernate/clock scale/hce enable, having pre/post notifications in the same function will make it easier to maintain. Additionally, supplement the description of power parameters for the pwr_change_notify callback. Fixes: 7eb584db73be ("ufs: refactor configuring power mode") Cc: stable(a)vger.kernel.org #6.11.x Signed-off-by: Peter Wang <peter.wang(a)mediatek.com> --- drivers/ufs/core/ufshcd.c | 7 ++++--- include/ufs/ufshcd.h | 10 ++++++---- 2 files changed, 10 insertions(+), 7 deletions(-) diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index abbe7135a977..814402e93a1e 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -4651,9 +4651,6 @@ static int ufshcd_change_power_mode(struct ufs_hba *hba, dev_err(hba->dev, "%s: power mode change failed %d\n", __func__, ret); } else { - ufshcd_vops_pwr_change_notify(hba, POST_CHANGE, NULL, - pwr_mode); - memcpy(&hba->pwr_info, pwr_mode, sizeof(struct ufs_pa_layer_attr)); } @@ -4682,6 +4679,10 @@ int ufshcd_config_pwr_mode(struct ufs_hba *hba, ret = ufshcd_change_power_mode(hba, &final_params); + if (!ret) + ufshcd_vops_pwr_change_notify(hba, POST_CHANGE, NULL, + &final_params); + return ret; } EXPORT_SYMBOL_GPL(ufshcd_config_pwr_mode); diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h index 3f68ae3e4330..1db754b4a4d6 100644 --- a/include/ufs/ufshcd.h +++ b/include/ufs/ufshcd.h @@ -308,7 +308,9 @@ struct ufs_pwr_mode_info { * to allow variant specific Uni-Pro initialization. * @pwr_change_notify: called before and after a power mode change * is carried out to allow vendor spesific capabilities - * to be set. + * to be set. PRE_CHANGE can modify final_params based + * on desired_pwr_mode, but POST_CHANGE must not alter + * the final_params parameter * @setup_xfer_req: called before any transfer request is issued * to set some things * @setup_task_mgmt: called before any task management request is issued @@ -350,9 +352,9 @@ struct ufs_hba_variant_ops { int (*link_startup_notify)(struct ufs_hba *, enum ufs_notify_change_status); int (*pwr_change_notify)(struct ufs_hba *, - enum ufs_notify_change_status status, - struct ufs_pa_layer_attr *, - struct ufs_pa_layer_attr *); + enum ufs_notify_change_status status, + struct ufs_pa_layer_attr *desired_pwr_mode, + struct ufs_pa_layer_attr *final_params); void (*setup_xfer_req)(struct ufs_hba *hba, int tag, bool is_scsi_cmd); void (*setup_task_mgmt)(struct ufs_hba *, int, u8); -- 2.18.0

2 months

3
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[PATCH V2 1/2] LoongArch: KVM: Protect kvm_check_requests() with SRCU

by Huacai Chen

When we enable lockdep we get such a warning: ============================= WARNING: suspicious RCU usage 6.12.0-rc7+ #1891 Tainted: G W ----------------------------- include/linux/kvm_host.h:1043 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by qemu-system-loo/948: #0: 90000001184a00a8 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0xf4/0xe20 [kvm] stack backtrace: CPU: 0 UID: 0 PID: 948 Comm: qemu-system-loo Tainted: G W 6.12.0-rc7+ #1891 Tainted: [W]=WARN Hardware name: Loongson Loongson-3A5000-7A1000-1w-CRB/Loongson-LS3A5000-7A1000-1w-CRB, BIOS vUDK2018-LoongArch-V2.0.0-prebeta9 10/21/2022 Stack : 0000000000000089 9000000005a0db9c 90000000071519c8 900000012c578000 900000012c57b920 0000000000000000 900000012c57b928 9000000007e53788 900000000815bcc8 900000000815bcc0 900000012c57b790 0000000000000001 0000000000000001 4b031894b9d6b725 0000000004dec000 90000001003299c0 0000000000000414 0000000000000001 000000000000002d 0000000000000003 0000000000000030 00000000000003b4 0000000004dec000 90000001184a0000 900000000806d000 9000000007e53788 00000000000000b4 0000000000000004 0000000000000004 0000000000000000 0000000000000000 9000000107baf600 9000000008916000 9000000007e53788 9000000005924778 0000000010000044 00000000000000b0 0000000000000004 0000000000000000 0000000000071c1d ... Call Trace: [<9000000005924778>] show_stack+0x38/0x180 [<90000000071519c4>] dump_stack_lvl+0x94/0xe4 [<90000000059eb754>] lockdep_rcu_suspicious+0x194/0x240 [<ffff8000022143bc>] kvm_gfn_to_hva_cache_init+0xfc/0x120 [kvm] [<ffff80000222ade4>] kvm_pre_enter_guest+0x3a4/0x520 [kvm] [<ffff80000222b3dc>] kvm_handle_exit+0x23c/0x480 [kvm] Fix it by protecting kvm_check_requests() with SRCU. Cc: stable(a)vger.kernel.org Signed-off-by: Huacai Chen <chenhuacai(a)loongson.cn> --- arch/loongarch/kvm/vcpu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c index cab1818be68d..d18a4a270415 100644 --- a/arch/loongarch/kvm/vcpu.c +++ b/arch/loongarch/kvm/vcpu.c @@ -240,7 +240,7 @@ static void kvm_late_check_requests(struct kvm_vcpu *vcpu) */ static int kvm_enter_guest_check(struct kvm_vcpu *vcpu) { - int ret; + int idx, ret; /* * Check conditions before entering the guest @@ -249,7 +249,9 @@ static int kvm_enter_guest_check(struct kvm_vcpu *vcpu) if (ret < 0) return ret; + idx = srcu_read_lock(&vcpu->kvm->srcu); ret = kvm_check_requests(vcpu); + srcu_read_unlock(&vcpu->kvm->srcu, idx); return ret; } -- 2.43.5

2 months

2
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[PATCH AUTOSEL 4.19] misc: eeprom: eeprom_93cx6: Add quirk for extra read clock cycle

by Sasha Levin

From: Parker Newman <pnewman(a)connecttech.com> [ Upstream commit 7738a7ab9d12c5371ed97114ee2132d4512e9fd5 ] Add a quirk similar to eeprom_93xx46 to add an extra clock cycle before reading data from the EEPROM. The 93Cx6 family of EEPROMs output a "dummy 0 bit" between the writing of the op-code/address from the host to the EEPROM and the reading of the actual data from the EEPROM. More info can be found on page 6 of the AT93C46 datasheet (linked below). Similar notes are found in other 93xx6 datasheets. In summary the read operation for a 93Cx6 EEPROM is: Write to EEPROM: 110[A5-A0] (9 bits) Read from EEPROM: 0[D15-D0] (17 bits) Where: 110 is the start bit and READ OpCode [A5-A0] is the address to read from 0 is a "dummy bit" preceding the actual data [D15-D0] is the actual data. Looking at the READ timing diagrams in the 93Cx6 datasheets the dummy bit should be clocked out on the last address bit clock cycle meaning it should be discarded naturally. However, depending on the hardware configuration sometimes this dummy bit is not discarded. This is the case with Exar PCI UARTs which require an extra clock cycle between sending the address and reading the data. Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-5193-SEEPROM-AT93C46… Reviewed-by: Andy Shevchenko <andriy.shevchenko(a)linux.intel.com> Signed-off-by: Parker Newman <pnewman(a)connecttech.com> Link: https://lore.kernel.org/r/0f23973efefccd2544705a0480b4ad4c2353e407.17278809… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- drivers/misc/eeprom/eeprom_93cx6.c | 10 ++++++++++ include/linux/eeprom_93cx6.h | 11 +++++++++++ 2 files changed, 21 insertions(+) diff --git a/drivers/misc/eeprom/eeprom_93cx6.c b/drivers/misc/eeprom/eeprom_93cx6.c index 0cf2c9d676be8..31c69642f13e0 100644 --- a/drivers/misc/eeprom/eeprom_93cx6.c +++ b/drivers/misc/eeprom/eeprom_93cx6.c @@ -195,6 +195,11 @@ void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom, const u8 word, eeprom_93cx6_write_bits(eeprom, command, PCI_EEPROM_WIDTH_OPCODE + eeprom->width); + if (has_quirk_extra_read_cycle(eeprom)) { + eeprom_93cx6_pulse_high(eeprom); + eeprom_93cx6_pulse_low(eeprom); + } + /* * Read the requested 16 bits. */ @@ -261,6 +266,11 @@ void eeprom_93cx6_readb(struct eeprom_93cx6 *eeprom, const u8 byte, eeprom_93cx6_write_bits(eeprom, command, PCI_EEPROM_WIDTH_OPCODE + eeprom->width + 1); + if (has_quirk_extra_read_cycle(eeprom)) { + eeprom_93cx6_pulse_high(eeprom); + eeprom_93cx6_pulse_low(eeprom); + } + /* * Read the requested 8 bits. */ diff --git a/include/linux/eeprom_93cx6.h b/include/linux/eeprom_93cx6.h index eb0b1988050ae..ec913059a5299 100644 --- a/include/linux/eeprom_93cx6.h +++ b/include/linux/eeprom_93cx6.h @@ -24,6 +24,8 @@ Supported chipsets: 93c46, 93c56 and 93c66. */ +#include <linux/bits.h> + /* * EEPROM operation defines. */ @@ -47,6 +49,7 @@ * @register_write(struct eeprom_93cx6 *eeprom): handler to * write to the eeprom register by using all reg_* fields. * @width: eeprom width, should be one of the PCI_EEPROM_WIDTH_* defines + * @quirks: eeprom or controller quirks * @drive_data: Set if we're driving the data line. * @reg_data_in: register field to indicate data input * @reg_data_out: register field to indicate data output @@ -63,6 +66,9 @@ struct eeprom_93cx6 { void (*register_write)(struct eeprom_93cx6 *eeprom); int width; + unsigned int quirks; +/* Some EEPROMs require an extra clock cycle before reading */ +#define PCI_EEPROM_QUIRK_EXTRA_READ_CYCLE BIT(0) char drive_data; char reg_data_in; @@ -84,3 +90,8 @@ extern void eeprom_93cx6_wren(struct eeprom_93cx6 *eeprom, bool enable); extern void eeprom_93cx6_write(struct eeprom_93cx6 *eeprom, u8 addr, u16 data); + +static inline bool has_quirk_extra_read_cycle(struct eeprom_93cx6 *eeprom) +{ + return eeprom->quirks & PCI_EEPROM_QUIRK_EXTRA_READ_CYCLE; +} -- 2.43.0

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[PATCH AUTOSEL 5.4] misc: eeprom: eeprom_93cx6: Add quirk for extra read clock cycle

by Sasha Levin

From: Parker Newman <pnewman(a)connecttech.com> [ Upstream commit 7738a7ab9d12c5371ed97114ee2132d4512e9fd5 ] Add a quirk similar to eeprom_93xx46 to add an extra clock cycle before reading data from the EEPROM. The 93Cx6 family of EEPROMs output a "dummy 0 bit" between the writing of the op-code/address from the host to the EEPROM and the reading of the actual data from the EEPROM. More info can be found on page 6 of the AT93C46 datasheet (linked below). Similar notes are found in other 93xx6 datasheets. In summary the read operation for a 93Cx6 EEPROM is: Write to EEPROM: 110[A5-A0] (9 bits) Read from EEPROM: 0[D15-D0] (17 bits) Where: 110 is the start bit and READ OpCode [A5-A0] is the address to read from 0 is a "dummy bit" preceding the actual data [D15-D0] is the actual data. Looking at the READ timing diagrams in the 93Cx6 datasheets the dummy bit should be clocked out on the last address bit clock cycle meaning it should be discarded naturally. However, depending on the hardware configuration sometimes this dummy bit is not discarded. This is the case with Exar PCI UARTs which require an extra clock cycle between sending the address and reading the data. Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-5193-SEEPROM-AT93C46… Reviewed-by: Andy Shevchenko <andriy.shevchenko(a)linux.intel.com> Signed-off-by: Parker Newman <pnewman(a)connecttech.com> Link: https://lore.kernel.org/r/0f23973efefccd2544705a0480b4ad4c2353e407.17278809… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- drivers/misc/eeprom/eeprom_93cx6.c | 10 ++++++++++ include/linux/eeprom_93cx6.h | 11 +++++++++++ 2 files changed, 21 insertions(+) diff --git a/drivers/misc/eeprom/eeprom_93cx6.c b/drivers/misc/eeprom/eeprom_93cx6.c index 36a2eb837371b..6b42ba6705d3f 100644 --- a/drivers/misc/eeprom/eeprom_93cx6.c +++ b/drivers/misc/eeprom/eeprom_93cx6.c @@ -186,6 +186,11 @@ void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom, const u8 word, eeprom_93cx6_write_bits(eeprom, command, PCI_EEPROM_WIDTH_OPCODE + eeprom->width); + if (has_quirk_extra_read_cycle(eeprom)) { + eeprom_93cx6_pulse_high(eeprom); + eeprom_93cx6_pulse_low(eeprom); + } + /* * Read the requested 16 bits. */ @@ -252,6 +257,11 @@ void eeprom_93cx6_readb(struct eeprom_93cx6 *eeprom, const u8 byte, eeprom_93cx6_write_bits(eeprom, command, PCI_EEPROM_WIDTH_OPCODE + eeprom->width + 1); + if (has_quirk_extra_read_cycle(eeprom)) { + eeprom_93cx6_pulse_high(eeprom); + eeprom_93cx6_pulse_low(eeprom); + } + /* * Read the requested 8 bits. */ diff --git a/include/linux/eeprom_93cx6.h b/include/linux/eeprom_93cx6.h index c860c72a921d0..3a485cc0e0fa0 100644 --- a/include/linux/eeprom_93cx6.h +++ b/include/linux/eeprom_93cx6.h @@ -11,6 +11,8 @@ Supported chipsets: 93c46, 93c56 and 93c66. */ +#include <linux/bits.h> + /* * EEPROM operation defines. */ @@ -34,6 +36,7 @@ * @register_write(struct eeprom_93cx6 *eeprom): handler to * write to the eeprom register by using all reg_* fields. * @width: eeprom width, should be one of the PCI_EEPROM_WIDTH_* defines + * @quirks: eeprom or controller quirks * @drive_data: Set if we're driving the data line. * @reg_data_in: register field to indicate data input * @reg_data_out: register field to indicate data output @@ -50,6 +53,9 @@ struct eeprom_93cx6 { void (*register_write)(struct eeprom_93cx6 *eeprom); int width; + unsigned int quirks; +/* Some EEPROMs require an extra clock cycle before reading */ +#define PCI_EEPROM_QUIRK_EXTRA_READ_CYCLE BIT(0) char drive_data; char reg_data_in; @@ -71,3 +77,8 @@ extern void eeprom_93cx6_wren(struct eeprom_93cx6 *eeprom, bool enable); extern void eeprom_93cx6_write(struct eeprom_93cx6 *eeprom, u8 addr, u16 data); + +static inline bool has_quirk_extra_read_cycle(struct eeprom_93cx6 *eeprom) +{ + return eeprom->quirks & PCI_EEPROM_QUIRK_EXTRA_READ_CYCLE; +} -- 2.43.0

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[PATCH AUTOSEL 5.10] misc: eeprom: eeprom_93cx6: Add quirk for extra read clock cycle

by Sasha Levin

From: Parker Newman <pnewman(a)connecttech.com> [ Upstream commit 7738a7ab9d12c5371ed97114ee2132d4512e9fd5 ] Add a quirk similar to eeprom_93xx46 to add an extra clock cycle before reading data from the EEPROM. The 93Cx6 family of EEPROMs output a "dummy 0 bit" between the writing of the op-code/address from the host to the EEPROM and the reading of the actual data from the EEPROM. More info can be found on page 6 of the AT93C46 datasheet (linked below). Similar notes are found in other 93xx6 datasheets. In summary the read operation for a 93Cx6 EEPROM is: Write to EEPROM: 110[A5-A0] (9 bits) Read from EEPROM: 0[D15-D0] (17 bits) Where: 110 is the start bit and READ OpCode [A5-A0] is the address to read from 0 is a "dummy bit" preceding the actual data [D15-D0] is the actual data. Looking at the READ timing diagrams in the 93Cx6 datasheets the dummy bit should be clocked out on the last address bit clock cycle meaning it should be discarded naturally. However, depending on the hardware configuration sometimes this dummy bit is not discarded. This is the case with Exar PCI UARTs which require an extra clock cycle between sending the address and reading the data. Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-5193-SEEPROM-AT93C46… Reviewed-by: Andy Shevchenko <andriy.shevchenko(a)linux.intel.com> Signed-off-by: Parker Newman <pnewman(a)connecttech.com> Link: https://lore.kernel.org/r/0f23973efefccd2544705a0480b4ad4c2353e407.17278809… Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- drivers/misc/eeprom/eeprom_93cx6.c | 10 ++++++++++ include/linux/eeprom_93cx6.h | 11 +++++++++++ 2 files changed, 21 insertions(+) diff --git a/drivers/misc/eeprom/eeprom_93cx6.c b/drivers/misc/eeprom/eeprom_93cx6.c index 9627294fe3e95..4c9827fe92173 100644 --- a/drivers/misc/eeprom/eeprom_93cx6.c +++ b/drivers/misc/eeprom/eeprom_93cx6.c @@ -186,6 +186,11 @@ void eeprom_93cx6_read(struct eeprom_93cx6 *eeprom, const u8 word, eeprom_93cx6_write_bits(eeprom, command, PCI_EEPROM_WIDTH_OPCODE + eeprom->width); + if (has_quirk_extra_read_cycle(eeprom)) { + eeprom_93cx6_pulse_high(eeprom); + eeprom_93cx6_pulse_low(eeprom); + } + /* * Read the requested 16 bits. */ @@ -252,6 +257,11 @@ void eeprom_93cx6_readb(struct eeprom_93cx6 *eeprom, const u8 byte, eeprom_93cx6_write_bits(eeprom, command, PCI_EEPROM_WIDTH_OPCODE + eeprom->width + 1); + if (has_quirk_extra_read_cycle(eeprom)) { + eeprom_93cx6_pulse_high(eeprom); + eeprom_93cx6_pulse_low(eeprom); + } + /* * Read the requested 8 bits. */ diff --git a/include/linux/eeprom_93cx6.h b/include/linux/eeprom_93cx6.h index c860c72a921d0..3a485cc0e0fa0 100644 --- a/include/linux/eeprom_93cx6.h +++ b/include/linux/eeprom_93cx6.h @@ -11,6 +11,8 @@ Supported chipsets: 93c46, 93c56 and 93c66. */ +#include <linux/bits.h> + /* * EEPROM operation defines. */ @@ -34,6 +36,7 @@ * @register_write(struct eeprom_93cx6 *eeprom): handler to * write to the eeprom register by using all reg_* fields. * @width: eeprom width, should be one of the PCI_EEPROM_WIDTH_* defines + * @quirks: eeprom or controller quirks * @drive_data: Set if we're driving the data line. * @reg_data_in: register field to indicate data input * @reg_data_out: register field to indicate data output @@ -50,6 +53,9 @@ struct eeprom_93cx6 { void (*register_write)(struct eeprom_93cx6 *eeprom); int width; + unsigned int quirks; +/* Some EEPROMs require an extra clock cycle before reading */ +#define PCI_EEPROM_QUIRK_EXTRA_READ_CYCLE BIT(0) char drive_data; char reg_data_in; @@ -71,3 +77,8 @@ extern void eeprom_93cx6_wren(struct eeprom_93cx6 *eeprom, bool enable); extern void eeprom_93cx6_write(struct eeprom_93cx6 *eeprom, u8 addr, u16 data); + +static inline bool has_quirk_extra_read_cycle(struct eeprom_93cx6 *eeprom) +{ + return eeprom->quirks & PCI_EEPROM_QUIRK_EXTRA_READ_CYCLE; +} -- 2.43.0

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