linux-kernel - Re: [PATCH] memory: jz4780_nemc: Only request IO memory the driver will use

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Message-Id: <RQJ6EQ.X0RPEZHBGXEN1@crapouillou.net>
Date:   Tue, 28 Jul 2020 14:52:03 +0200
From:   Paul Cercueil <paul@...pouillou.net>
To:     Krzysztof Kozlowski <krzk@...nel.org>
Cc:     od@...c.me, linux-kernel@...r.kernel.org,
        "H . Nikolaus Schaller" <hns@...delico.com>
Subject: Re: [PATCH] memory: jz4780_nemc: Only request IO memory the driver
 will use



Le mar. 28 juil. 2020 à 11:21, Krzysztof Kozlowski <krzk@...nel.org> a 
écrit :
> On Mon, Jul 27, 2020 at 06:20:34PM +0200, Paul Cercueil wrote:
>>  The driver only uses the registers up to offset 0x54. Since the 
>> EFUSE
>>  registers are in the middle of the NEMC registers, we only request
>>  the registers we will use for now - that way the EFUSE driver can
>>  probe too.
>> 
>>  Tested-by: H. Nikolaus Schaller <hns@...delico.com>
>>  Signed-off-by: Paul Cercueil <paul@...pouillou.net>
>>  ---
>>   drivers/memory/jz4780-nemc.c | 15 ++++++++++++++-
>>   1 file changed, 14 insertions(+), 1 deletion(-)
>> 
>>  diff --git a/drivers/memory/jz4780-nemc.c 
>> b/drivers/memory/jz4780-nemc.c
>>  index b232ed279fc3..647267ea8c63 100644
>>  --- a/drivers/memory/jz4780-nemc.c
>>  +++ b/drivers/memory/jz4780-nemc.c
>>  @@ -8,6 +8,7 @@
>> 
>>   #include <linux/clk.h>
>>   #include <linux/init.h>
>>  +#include <linux/io.h>
>>   #include <linux/math64.h>
>>   #include <linux/of.h>
>>   #include <linux/of_address.h>
>>  @@ -288,7 +289,19 @@ static int jz4780_nemc_probe(struct 
>> platform_device *pdev)
>>   	nemc->dev = dev;
>> 
>>   	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>  -	nemc->base = devm_ioremap_resource(dev, res);
>>  +
>>  +	/*
>>  +	 * The driver only uses the registers up to offset 0x54. Since 
>> the EFUSE
>>  +	 * registers are in the middle of the NEMC registers, we only 
>> request
>>  +	 * the registers we will use for now - that way the EFUSE driver 
>> can
>>  +	 * probe too.
>>  +	 */
>>  +	if (!devm_request_mem_region(dev, res->start, 0x54, 
>> dev_name(dev))) {
>>  +		dev_err(dev, "unable to request I/O memory region\n");
>>  +		return -EBUSY;
>>  +	}
>>  +
>>  +	nemc->base = devm_ioremap(dev, res->start, resource_size(res));
> 
> Shouldn't you map only 0x54 size as well?

I can do that.

Cheers,
-Paul