From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [203.10.76.45]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx.ozlabs.org", Issuer "CA Cert Signing Authority" (verified OK)) by bilbo.ozlabs.org (Postfix) with ESMTPS id 66454B7B66 for ; Thu, 23 Jul 2009 21:30:50 +1000 (EST) Received: from exprod5og112.obsmtp.com (exprod5og112.obsmtp.com [64.18.0.24]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 2862FDDD0B for ; Thu, 23 Jul 2009 21:30:46 +1000 (EST) Message-ID: <4A684A03.5010803@gefanuc.com> Date: Thu, 23 Jul 2009 12:31:15 +0100 From: Martyn Welch MIME-Version: 1.0 To: Benjamin Herrenschmidt Subject: Re: [PATCH 2/5] Mechanism to enable use Generic NVRAM driver for different size chips References: <20090702154928.31202.65107.stgit@ES-J7S4D2J.amer.consind.ge.com> <20090702161224.31202.65236.stgit@ES-J7S4D2J.amer.consind.ge.com> <1248334988.3367.77.camel@pasglop> In-Reply-To: <1248334988.3367.77.camel@pasglop> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Benjamin Herrenschmidt wrote: > On Thu, 2009-07-02 at 17:12 +0100, Martyn Welch wrote: > >> Remove the reliance on a staticly defined NVRAM size, allowing platforms to support NVRAMs with sizes differing from the standard. A fall back value is provided for platforms not supporting this extension. >> >> Signed-off-by: Martyn Welch >> > > What about other archs that use this driver ? They would also need > that new nvram_size() ... > I'm fairly confident that this driver is solely used by the PowerPC architecture. The config option being set in arch/powerpc/Kconfig[1]. Other than the obvious matches in drivers/char/Makefile[2] and powerpc defconfigs, the only other places I can find the option being used are: * As a requirement for CONFIG_NVRAM on the PowerPC platform in drivers/char/Kconfig[3] * In "include/config/auto.conf" and "include/linux/autoconf.h". Are these for generation of generic configs? Martyn [1] http://git.kernel.org/gitweb.cgi?p=linux/kernel/git/benh/powerpc.git;a=blob;f=arch/powerpc/Kconfig#l145 [2] http://git.kernel.org/gitweb.cgi?p=linux/kernel/git/benh/powerpc.git;a=blob;f=drivers/char/Makefile#l83 [3] http://git.kernel.org/gitweb.cgi?p=linux/kernel/git/benh/powerpc.git;a=blob;f=drivers/char/Kconfig#l777 > BTW. This patch touches non-arch code so should at least be CCed to lkml > > Cheers, > Ben. > > >> --- >> >> arch/powerpc/include/asm/nvram.h | 3 +++ >> arch/powerpc/kernel/setup_32.c | 8 ++++++++ >> drivers/char/generic_nvram.c | 27 ++++++++++++++++++++------- >> 3 files changed, 31 insertions(+), 7 deletions(-) >> >> diff --git a/arch/powerpc/include/asm/nvram.h b/arch/powerpc/include/asm/nvram.h >> index efde5ac..71df8b2 100644 >> --- a/arch/powerpc/include/asm/nvram.h >> +++ b/arch/powerpc/include/asm/nvram.h >> @@ -107,6 +107,9 @@ extern void pmac_xpram_write(int xpaddr, u8 data); >> /* Synchronize NVRAM */ >> extern void nvram_sync(void); >> >> +/* Determine NVRAM size */ >> +extern ssize_t nvram_size(void); >> + >> /* Normal access to NVRAM */ >> extern unsigned char nvram_read_byte(int i); >> extern void nvram_write_byte(unsigned char c, int i); >> diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c >> index 1d15424..28f7570 100644 >> --- a/arch/powerpc/kernel/setup_32.c >> +++ b/arch/powerpc/kernel/setup_32.c >> @@ -208,6 +208,14 @@ void nvram_write_byte(unsigned char val, int addr) >> } >> EXPORT_SYMBOL(nvram_write_byte); >> >> +ssize_t nvram_size(void) >> +{ >> + if (ppc_md.nvram_size) >> + return ppc_md.nvram_size(); >> + return -1; >> +} >> +EXPORT_SYMBOL(nvram_size); >> + >> void nvram_sync(void) >> { >> if (ppc_md.nvram_sync) >> diff --git a/drivers/char/generic_nvram.c b/drivers/char/generic_nvram.c >> index a00869c..e5f71f3 100644 >> --- a/drivers/char/generic_nvram.c >> +++ b/drivers/char/generic_nvram.c >> @@ -2,7 +2,7 @@ >> * Generic /dev/nvram driver for architectures providing some >> * "generic" hooks, that is : >> * >> - * nvram_read_byte, nvram_write_byte, nvram_sync >> + * nvram_read_byte, nvram_write_byte, nvram_sync, nvram_size >> * >> * Note that an additional hook is supported for PowerMac only >> * for getting the nvram "partition" informations >> @@ -28,6 +28,8 @@ >> >> #define NVRAM_SIZE 8192 >> >> +static ssize_t nvram_len; >> + >> static loff_t nvram_llseek(struct file *file, loff_t offset, int origin) >> { >> lock_kernel(); >> @@ -36,7 +38,7 @@ static loff_t nvram_llseek(struct file *file, loff_t offset, int origin) >> offset += file->f_pos; >> break; >> case 2: >> - offset += NVRAM_SIZE; >> + offset += nvram_len; >> break; >> } >> if (offset < 0) { >> @@ -56,9 +58,9 @@ static ssize_t read_nvram(struct file *file, char __user *buf, >> >> if (!access_ok(VERIFY_WRITE, buf, count)) >> return -EFAULT; >> - if (*ppos >= NVRAM_SIZE) >> + if (*ppos >= nvram_len) >> return 0; >> - for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count) >> + for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count) >> if (__put_user(nvram_read_byte(i), p)) >> return -EFAULT; >> *ppos = i; >> @@ -74,9 +76,9 @@ static ssize_t write_nvram(struct file *file, const char __user *buf, >> >> if (!access_ok(VERIFY_READ, buf, count)) >> return -EFAULT; >> - if (*ppos >= NVRAM_SIZE) >> + if (*ppos >= nvram_len) >> return 0; >> - for (i = *ppos; count > 0 && i < NVRAM_SIZE; ++i, ++p, --count) { >> + for (i = *ppos; count > 0 && i < nvram_len; ++i, ++p, --count) { >> if (__get_user(c, p)) >> return -EFAULT; >> nvram_write_byte(c, i); >> @@ -133,9 +135,20 @@ static struct miscdevice nvram_dev = { >> >> int __init nvram_init(void) >> { >> + int ret = 0; >> + >> printk(KERN_INFO "Generic non-volatile memory driver v%s\n", >> NVRAM_VERSION); >> - return misc_register(&nvram_dev); >> + ret = misc_register(&nvram_dev); >> + if (ret != 0) >> + goto out; >> + >> + nvram_len = nvram_size(); >> + if (nvram_len < 0) >> + nvram_len = NVRAM_SIZE; >> + >> +out: >> + return ret; >> } >> >> void __exit nvram_cleanup(void) >> > > -- Martyn Welch MEng MPhil MIET (Principal Software Engineer) T:+44(0)1327322748 GE Fanuc Intelligent Platforms Ltd, |Registered in England and Wales Tove Valley Business Park, Towcester, |(3828642) at 100 Barbirolli Square, Northants, NN12 6PF, UK T:+44(0)1327359444 |Manchester,M2 3AB VAT:GB 927559189