mtd: rawnand: stm32_fmc2: avoid overlapping mappings on ECC buffer

Avoid below overlapping mappings by using a contiguous
non-cacheable buffer.

[    4.077708] DMA-API: stm32_fmc2_nfc 48810000.nand-controller: cacheline tracking EEXIST,
overlapping mappings aren't supported
[    4.089103] WARNING: CPU: 1 PID: 44 at kernel/dma/debug.c:568 add_dma_entry+0x23c/0x300
[    4.097071] Modules linked in:
[    4.100101] CPU: 1 PID: 44 Comm: kworker/u4:2 Not tainted 6.1.82 #1
[    4.106346] Hardware name: STMicroelectronics STM32MP257F VALID1 SNOR / MB1704 (LPDDR4 Power discrete) + MB1703 + MB1708 (SNOR MB1730) (DT)
[    4.118824] Workqueue: events_unbound deferred_probe_work_func
[    4.124674] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[    4.131624] pc : add_dma_entry+0x23c/0x300
[    4.135658] lr : add_dma_entry+0x23c/0x300
[    4.139792] sp : ffff800009dbb490
[    4.143016] x29: ffff800009dbb4a0 x28: 0000000004008022 x27: ffff8000098a6000
[    4.150174] x26: 0000000000000000 x25: ffff8000099e7000 x24: ffff8000099e7de8
[    4.157231] x23: 00000000ffffffff x22: 0000000000000000 x21: ffff8000098a6a20
[    4.164388] x20: ffff000080964180 x19: ffff800009819ba0 x18: 0000000000000006
[    4.171545] x17: 6361727420656e69 x16: 6c6568636163203a x15: 72656c6c6f72746e
[    4.178602] x14: 6f632d646e616e2e x13: ffff800009832f58 x12: 00000000000004ec
[    4.185759] x11: 00000000000001a4 x10: ffff80000988af58 x9 : ffff800009832f58
[    4.192916] x8 : 00000000ffffefff x7 : ffff80000988af58 x6 : 80000000fffff000
[    4.199972] x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 0000000000000000
[    4.207128] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000812d2c40
[    4.214185] Call trace:
[    4.216605]  add_dma_entry+0x23c/0x300
[    4.220338]  debug_dma_map_sg+0x198/0x350
[    4.224373]  __dma_map_sg_attrs+0xa0/0x110
[    4.228411]  dma_map_sg_attrs+0x10/0x2c
[    4.232247]  stm32_fmc2_nfc_xfer.isra.0+0x1c8/0x3fc
[    4.237088]  stm32_fmc2_nfc_seq_read_page+0xc8/0x174
[    4.242127]  nand_read_oob+0x1d4/0x8e0
[    4.245861]  mtd_read_oob_std+0x58/0x84
[    4.249596]  mtd_read_oob+0x90/0x150
[    4.253231]  mtd_read+0x68/0xac

Signed-off-by: Christophe Kerello <[email protected]>
Cc: [email protected]
Fixes: 2cd457f ("mtd: rawnand: stm32_fmc2: add STM32 FMC2 NAND flash controller driver")
Signed-off-by: Miquel Raynal <[email protected]>

Author: Christophe Kerello

drivers/mtd/nand/raw/stm32_fmc2_nand.c

@@ -272,6 +272,7 @@ struct stm32_fmc2_nfc {
 	struct sg_table dma_data_sg;
 	struct sg_table dma_ecc_sg;
 	u8 *ecc_buf;
+	dma_addr_t dma_ecc_addr;
 	int dma_ecc_len;
 	u32 tx_dma_max_burst;
 	u32 rx_dma_max_burst;
@@ -902,17 +903,10 @@ static int stm32_fmc2_nfc_xfer(struct nand_chip *chip, const u8 *buf,
 
 	if (!write_data && !raw) {
 		/* Configure DMA ECC status */
-		p = nfc->ecc_buf;
 		for_each_sg(nfc->dma_ecc_sg.sgl, sg, eccsteps, s) {
-			sg_set_buf(sg, p, nfc->dma_ecc_len);
-			p += nfc->dma_ecc_len;
-		}
-
-		ret = dma_map_sg(nfc->dev, nfc->dma_ecc_sg.sgl,
-				 eccsteps, dma_data_dir);
-		if (!ret) {
-			ret = -EIO;
-			goto err_unmap_data;
+			sg_dma_address(sg) = nfc->dma_ecc_addr +
+					     s * nfc->dma_ecc_len;
+			sg_dma_len(sg) = nfc->dma_ecc_len;
 		}
 
 		desc_ecc = dmaengine_prep_slave_sg(nfc->dma_ecc_ch,
@@ -921,15 +915,15 @@ static int stm32_fmc2_nfc_xfer(struct nand_chip *chip, const u8 *buf,
 						   DMA_PREP_INTERRUPT);
 		if (!desc_ecc) {
 			ret = -ENOMEM;
-			goto err_unmap_ecc;
+			goto err_unmap_data;
 		}
 
 		reinit_completion(&nfc->dma_ecc_complete);
 		desc_ecc->callback = stm32_fmc2_nfc_dma_callback;
 		desc_ecc->callback_param = &nfc->dma_ecc_complete;
 		ret = dma_submit_error(dmaengine_submit(desc_ecc));
 		if (ret)
-			goto err_unmap_ecc;
+			goto err_unmap_data;
 
 		dma_async_issue_pending(nfc->dma_ecc_ch);
 	}
@@ -949,7 +943,7 @@ static int stm32_fmc2_nfc_xfer(struct nand_chip *chip, const u8 *buf,
 		if (!write_data && !raw)
 			dmaengine_terminate_all(nfc->dma_ecc_ch);
 		ret = -ETIMEDOUT;
-		goto err_unmap_ecc;
+		goto err_unmap_data;
 	}
 
 	/* Wait DMA data transfer completion */
@@ -969,11 +963,6 @@ static int stm32_fmc2_nfc_xfer(struct nand_chip *chip, const u8 *buf,
 		}
 	}
 
-err_unmap_ecc:
-	if (!write_data && !raw)
-		dma_unmap_sg(nfc->dev, nfc->dma_ecc_sg.sgl,
-			     eccsteps, dma_data_dir);
-
 err_unmap_data:
 	dma_unmap_sg(nfc->dev, nfc->dma_data_sg.sgl, eccsteps, dma_data_dir);
 
@@ -1610,7 +1599,8 @@ static int stm32_fmc2_nfc_dma_setup(struct stm32_fmc2_nfc *nfc)
 		return ret;
 
 	/* Allocate a buffer to store ECC status registers */
-	nfc->ecc_buf = devm_kzalloc(nfc->dev, FMC2_MAX_ECC_BUF_LEN, GFP_KERNEL);
+	nfc->ecc_buf = dmam_alloc_coherent(nfc->dev, FMC2_MAX_ECC_BUF_LEN,
+					   &nfc->dma_ecc_addr, GFP_KERNEL);
 	if (!nfc->ecc_buf)
 		return -ENOMEM;