linux-kernel - [PATCH 1/2] habanalabs: report correct dram size in info ioctl

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Date:   Fri,  1 Jan 2021 15:16:25 +0200
From:   Oded Gabbay <ogabbay@...nel.org>
To:     linux-kernel@...r.kernel.org
Cc:     Ofir Bitton <obitton@...ana.ai>
Subject: [PATCH 1/2] habanalabs: report correct dram size in info ioctl

From: Ofir Bitton <obitton@...ana.ai>

In case MMU is enabled, we must take MMU page size into
consideration when reporting dram size to the user.
This is because the MMU page size can be a value which is NOT
a power-of-2 value. As a result, the total DRAM size (which is always
a power-of-2 value) needed to be rounded-down.

Signed-off-by: Ofir Bitton <obitton@...ana.ai>
Reviewed-by: Oded Gabbay <ogabbay@...nel.org>
Signed-off-by: Oded Gabbay <ogabbay@...nel.org>
---
 drivers/misc/habanalabs/common/habanalabs_ioctl.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/habanalabs/common/habanalabs_ioctl.c b/drivers/misc/habanalabs/common/habanalabs_ioctl.c
index 64a82c966836..b83ee32ae569 100644
--- a/drivers/misc/habanalabs/common/habanalabs_ioctl.c
+++ b/drivers/misc/habanalabs/common/habanalabs_ioctl.c
@@ -62,7 +62,13 @@ static int hw_ip_info(struct hl_device *hdev, struct hl_info_args *args)
 			prop->dmmu.start_addr : prop->dram_user_base_address;
 	hw_ip.tpc_enabled_mask = prop->tpc_enabled_mask;
 	hw_ip.sram_size = prop->sram_size - sram_kmd_size;
-	hw_ip.dram_size = prop->dram_size - dram_kmd_size;
+
+	if (hdev->mmu_enable)
+		hw_ip.dram_size = rounddown(prop->dram_size - dram_kmd_size,
+							prop->dram_page_size);
+	else
+		hw_ip.dram_size = prop->dram_size - dram_kmd_size;
+
 	if (hw_ip.dram_size > PAGE_SIZE)
 		hw_ip.dram_enabled = 1;
 	hw_ip.dram_page_size = prop->dram_page_size;
-- 
2.25.1