• Guo Ren's avatar
    csky: Tightly-Coupled Memory or Sram support · f525bb2c
    Guo Ren authored
    The implementation are not only used by TCM but also used by sram on
    SOC bus. It follow existed linux tcm software interface, so that old
    tcm application codes could be re-used directly.
    
    Software interface list in asm/tcm.h:
     - Variables/Const: 	__tcmdata, __tcmconst
     - Functions:		__tcmfunc, __tcmlocalfunc
     - Malloc/Free:		tcm_alloc, tcm_free
    
    In linux menuconfig:
     - Choose a TCM contain instrctions + data or separated in ITCM/DTCM.
     - Determine TCM_BASE (DTCM_BASE) in phyiscal address.
     - Determine size of TCM or ITCM(DTCM) in page counts.
    
    Here is hello tcm example from Documentation/arm/tcm.rst which could
    be directly used:
    
    /* Uninitialized data */
    static u32 __tcmdata tcmvar;
    /* Initialized data */
    static u32 __tcmdata tcmassigned = 0x2BADBABEU;
    /* Constant */
    static const u32 __tcmconst tcmconst = 0xCAFEBABEU;
    
    static void __tcmlocalfunc tcm_to_tcm(void)
    {
    	int i;
    	for (i = 0; i < 100; i++)
    		tcmvar ++;
    }
    
    static void __tcmfunc hello_tcm(void)
    {
    	/* Some abstract code that runs in ITCM */
    	int i;
    	for (i = 0; i < 100; i++) {
    		tcmvar ++;
    	}
    	tcm_to_tcm();
    }
    
    static void __init test_tcm(void)
    {
    	u32 *tcmem;
    	int i;
    
    	hello_tcm();
    	printk("Hello TCM executed from ITCM RAM\n");
    
    	printk("TCM variable from testrun: %u @ %p\n", tcmvar, &tcmvar);
    	tcmvar = 0xDEADBEEFU;
    	printk("TCM variable: 0x%x @ %p\n", tcmvar, &tcmvar);
    
    	printk("TCM assigned variable: 0x%x @ %p\n", tcmassigned, &tcmassigned);
    
    	printk("TCM constant: 0x%x @ %p\n", tcmconst, &tcmconst);
    
    	/* Allocate some TCM memory from the pool */
    	tcmem = tcm_alloc(20);
    	if (tcmem) {
    		printk("TCM Allocated 20 bytes of TCM @ %p\n", tcmem);
    		tcmem[0] = 0xDEADBEEFU;
    		tcmem[1] = 0x2BADBABEU;
    		tcmem[2] = 0xCAFEBABEU;
    		tcmem[3] = 0xDEADBEEFU;
    		tcmem[4] = 0x2BADBABEU;
    		for (i = 0; i < 5; i++)
    			printk("TCM tcmem[%d] = %08x\n", i, tcmem[i]);
    		tcm_free(tcmem, 20);
    	}
    }
    
    TODO:
     - Separate fixup mapping from highmem
     - Support abiv1
    Signed-off-by: default avatarGuo Ren <guoren@linux.alibaba.com>
    f525bb2c
tcm.c 3.76 KB