mm_drv: tlb: Fix mapped page in bank calculation

The initial implementation was broken during improvements.
There was incorrect assumption that all pages are unmapped at
initials state. In reality at the beginning whole memory is
powered on, so we should mark all pages as mapped. Later in
initialization code unused pages are unmapped and if after this
some banks become empty (all pages unmapped), the power is
switched off.

Signed-off-by: Jaroslaw Stelter <[email protected]>

Author: jxstelter

drivers/mm/mm_drv_bank.c

@@ -15,32 +15,30 @@
  */
 
 #include <zephyr/kernel.h>
-
+#include <zephyr/sys/__assert.h>
 #include <zephyr/drivers/mm/mm_drv_bank.h>
 #include <zephyr/sys/mem_stats.h>
 
 void sys_mm_drv_bank_init(struct mem_drv_bank *bank, uint32_t bank_pages)
 {
-	bank->unmapped_pages = bank_pages;
-	bank->mapped_pages = 0;
-	bank->max_mapped_pages = 0;
+	bank->unmapped_pages = 0;
+	bank->mapped_pages = bank_pages;
+	bank->max_mapped_pages = bank_pages;
 }
 
 uint32_t sys_mm_drv_bank_page_mapped(struct mem_drv_bank *bank)
 {
 	bank->unmapped_pages--;
 	bank->mapped_pages++;
-	if (bank->mapped_pages > bank->max_mapped_pages) {
-		bank->max_mapped_pages = bank->mapped_pages;
-	}
+	__ASSERT_NO_MSG(bank->mapped_pages <= bank->max_mapped_pages);
 	return bank->mapped_pages;
 }
 
 uint32_t sys_mm_drv_bank_page_unmapped(struct mem_drv_bank *bank)
 {
 	bank->unmapped_pages++;
 	bank->mapped_pages--;
-
+	__ASSERT_NO_MSG(bank->unmapped_pages <= bank->max_mapped_pages);
 	return bank->unmapped_pages;
 }
 

drivers/mm/mm_drv_intel_adsp_mtl_tlb.c

@@ -378,7 +378,7 @@ int sys_mm_drv_unmap_page(void *virt)
 		sys_mm_drv_report_page_usage();
 #endif
 
-		if (sys_mm_drv_bank_page_unmapped(&hpsram_bank[bank_idx]) == 0) {
+		if (sys_mm_drv_bank_page_unmapped(&hpsram_bank[bank_idx]) == SRAM_BANK_PAGE_NUM) {
 			sys_mm_drv_hpsram_pwr(bank_idx, false, false);
 		}
 	}
@@ -649,7 +649,7 @@ static int sys_mm_drv_mm_init(const struct device *dev)
 	 */
 	for (int i = 0; i < L2_SRAM_BANK_NUM; i++) {
 		sys_mm_drv_bank_init(&hpsram_bank[i],
-				     SRAM_BANK_SIZE / CONFIG_MM_DRV_PAGE_SIZE);
+				     SRAM_BANK_PAGE_NUM);
 	}
 #ifdef CONFIG_SOC_INTEL_COMM_WIDGET
 	used_pages = L2_SRAM_BANK_NUM * SRAM_BANK_SIZE / CONFIG_MM_DRV_PAGE_SIZE;

include/zephyr/drivers/mm/mm_drv_bank.h

@@ -21,6 +21,8 @@
 #include <zephyr/sys/mem_stats.h>
 #include <stdint.h>
 
+#define SRAM_BANK_PAGE_NUM   (SRAM_BANK_SIZE / CONFIG_MM_DRV_PAGE_SIZE)
+
 struct mem_drv_bank {
 	uint32_t  unmapped_pages;
 	uint32_t  mapped_pages;
@@ -32,7 +34,9 @@ struct mem_drv_bank {
  *
  * The driver may wish to track various information about the memory banks
  * that it uses. This routine will initialize a generic structure containing
- * that information.
+ * that information. Since at the power on all memory banks are switched on
+ * it will start with all pages mapped. In next phase of driver initialization
+ * unused pages will be unmapped.
  *
  * @param bank Pointer to the memory bank structure used for tracking
  * @param bank_pages Number of pages in the memory bank

tests/drivers/mm/sys_mm_drv_bank/src/main.c

@@ -34,10 +34,15 @@ ZTEST(sys_mm_bank_api, test_sys_mm_drv_bank)
 	struct sys_memory_stats stats;
 	struct sys_memory_stats expected;
 	uint32_t  count;
+	uint32_t index;
 
 	/* Verify that the initialization routine works as expected. */
-
+	/* It set mapped state for all pages                         */
 	sys_mm_drv_bank_init(&bank_data, BANK_PAGES);
+	/* Now unmap all pages */
+	for (index = 0; index < BANK_PAGES; index++) {
+		sys_mm_drv_bank_page_unmapped(&bank_data);
+	}
 
 	expected.free_bytes = EXPECTED(BANK_PAGES);
 	expected.allocated_bytes = EXPECTED(0);