[PATCH] i2c: xgene-slimpro: Simplify PCC shared memory region handling

[Sudeep Holla]

The PCC driver now handles mapping and unmapping of shared memory
areas as part of pcc_mbox_{request,free}_channel(). Without these before,
this xgene-slimpro I2C driver did handling of those mappings like several
other PCC mailbox client drivers.

There were redundant operations, leading to unnecessary code. Maintaining
the consistency across these driver was harder due to scattered handling
of shmem.

Just use the mapped shmem and remove all redundant operations from this
driver.

Cc: Andi Shyti <andi.shyti@xxxxxxxxxx>
Cc: linux-i2c@xxxxxxxxxxxxxxx
Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
---
 drivers/i2c/busses/i2c-xgene-slimpro.c | 39 +++-----------------------
 1 file changed, 4 insertions(+), 35 deletions(-)

Hi,

This is just resend of the same patch that was part of a series [1].
Only core PCC mailbox changes were merged during v6.15 merge window.
So dropping all the maintainer(Andi) acks and reposting it so that it can
be picked up for v6.16 via maintainers tree.

Regards,
Sudeep

[1] https://lore.kernel.org/all/20250313-pcc_fixes_updates-v3-10-019a4aa74d0f@xxxxxxx/

diff --git a/drivers/i2c/busses/i2c-xgene-slimpro.c b/drivers/i2c/busses/i2c-xgene-slimpro.c
index 663fe5604dd6..a0880f4a056d 100644
--- a/drivers/i2c/busses/i2c-xgene-slimpro.c
+++ b/drivers/i2c/busses/i2c-xgene-slimpro.c
@@ -101,8 +101,6 @@ struct slimpro_i2c_dev {
 	struct completion rd_complete;
 	u8 dma_buffer[I2C_SMBUS_BLOCK_MAX + 1]; /* dma_buffer[0] is used for length */
 	u32 *resp_msg;
-	phys_addr_t comm_base_addr;
-	void *pcc_comm_addr;
 };
 
 #define to_slimpro_i2c_dev(cl)	\
@@ -148,7 +146,8 @@ static void slimpro_i2c_rx_cb(struct mbox_client *cl, void *mssg)
 static void slimpro_i2c_pcc_rx_cb(struct mbox_client *cl, void *msg)
 {
 	struct slimpro_i2c_dev *ctx = to_slimpro_i2c_dev(cl);
-	struct acpi_pcct_shared_memory *generic_comm_base = ctx->pcc_comm_addr;
+	struct acpi_pcct_shared_memory __iomem *generic_comm_base =
+							ctx->pcc_chan->shmem;
 
 	/* Check if platform sends interrupt */
 	if (!xgene_word_tst_and_clr(&generic_comm_base->status,
@@ -169,7 +168,8 @@ static void slimpro_i2c_pcc_rx_cb(struct mbox_client *cl, void *msg)
 
 static void slimpro_i2c_pcc_tx_prepare(struct slimpro_i2c_dev *ctx, u32 *msg)
 {
-	struct acpi_pcct_shared_memory *generic_comm_base = ctx->pcc_comm_addr;
+	struct acpi_pcct_shared_memory __iomem *generic_comm_base =
+							ctx->pcc_chan->shmem;
 	u32 *ptr = (void *)(generic_comm_base + 1);
 	u16 status;
 	int i;
@@ -464,15 +464,12 @@ static int xgene_slimpro_i2c_probe(struct platform_device *pdev)
 	} else {
 		struct pcc_mbox_chan *pcc_chan;
 		const struct acpi_device_id *acpi_id;
-		int version = XGENE_SLIMPRO_I2C_V1;
 
 		acpi_id = acpi_match_device(pdev->dev.driver->acpi_match_table,
 					    &pdev->dev);
 		if (!acpi_id)
 			return -EINVAL;
 
-		version = (int)acpi_id->driver_data;
-
 		if (device_property_read_u32(&pdev->dev, "pcc-channel",
 					     &ctx->mbox_idx))
 			ctx->mbox_idx = MAILBOX_I2C_INDEX;
@@ -494,34 +491,6 @@ static int xgene_slimpro_i2c_probe(struct platform_device *pdev)
 			goto mbox_err;
 		}
 
-		/*
-		 * This is the shared communication region
-		 * for the OS and Platform to communicate over.
-		 */
-		ctx->comm_base_addr = pcc_chan->shmem_base_addr;
-		if (ctx->comm_base_addr) {
-			if (version == XGENE_SLIMPRO_I2C_V2)
-				ctx->pcc_comm_addr = memremap(
-							ctx->comm_base_addr,
-							pcc_chan->shmem_size,
-							MEMREMAP_WT);
-			else
-				ctx->pcc_comm_addr = memremap(
-							ctx->comm_base_addr,
-							pcc_chan->shmem_size,
-							MEMREMAP_WB);
-		} else {
-			dev_err(&pdev->dev, "Failed to get PCC comm region\n");
-			rc = -ENOENT;
-			goto mbox_err;
-		}
-
-		if (!ctx->pcc_comm_addr) {
-			dev_err(&pdev->dev,
-				"Failed to ioremap PCC comm region\n");
-			rc = -ENOMEM;
-			goto mbox_err;
-		}
 	}
 	rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
 	if (rc)
-- 
2.34.1